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Sample records for cyp17a1 mutations causing

  1. CYP17A1 intron mutation causing cryptic splicing in 17α-hydroxylase deficiency.

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    Daw-Yang Hwang

    Full Text Available 17α-Hydroxylase/17, 20-lyase deficiency (17OHD is an autosomal recessive disease causing congenital adrenal hyperplasia and a rare cause of hypertension with hypokalemia. The CYP17A1 gene mutation leads to 17OHD and its clinical features. We described an 18 y/o female with clinical features of 17α-hydroxylase/17, 20-lyase deficiency and characterized the functional consequences of an intronic CYP17A1 mutation. The coding regions and flanking intronic bases of the CYP17A1 gene were amplified by PCR and sequenced. The patient is a compound heterozygote for the previously described p.R358X and IVS1 +2T>C mutations. A first intron splice donor site mutation was re-created in minigene and full-length expression vectors. Pre-mRNA splicing of the variant CYP17A1 intron was studied in transfected cells and in a transformed lymphoblastoid cell line. When the full-length CYP17A1 gene and minigene containing the intronic mutation was expressed in transfected cells, the majority (>90% of mRNA transcripts were incorrectly spliced. Only the p.R358X transcript was detected in the EBV-transformed lymphoblastoid cell line. The IVS1 +2T>C mutation abolished most 17α-hydroxylase/17, 20-lyase enzyme activity by aberrant mRNA splicing to an intronic pseudo-exon, causing a frame shift and early termination.

  2. 罕见的CYP17A1基因外显子剪接突变导致17α-羟化酶缺陷的分子病因学研究%An unique exonic splicing mutation in the CYPI7AI gene as the cause of steroid 17α-hydroxylase deficiency

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    韩兵; 朱惠; 陆颖理; 吴万龄; 宋怀东; 陈名道; 乔洁; 刘炳丽; 刘威; 吴佳君; 潘春明; 姜鹤; 顾婷; 姜博仁

    2011-01-01

    目的 对一例46XY性发育异常的患者进行CYP17A1致病基因分析,并探讨新的突变对患者表型的影响.方法 对患者及其父母的CYP17A1基因的8个外显子进行PCR扩增,扩增产物直接测序.将野生型和含有新突变位点的突变型PCR片段连入表达载体,构建Mini-gene系统,转染HEK-293T细胞,RT-PCR观察新突变位点对剪切的影响.进一步构建野生型和剪切异常的CYP17A1 cDNA全长表达质粒,转染HEK-293T细胞,体外检测CYP17A1酶活性.结果 基因分析显示患者的CYP17A1基因为复合杂合突变,其中一个等位基因为外显子6中c.985_987delinsAA突变,另一等位基因含有新的同义突变(c.1263 G>A:GCG>GCA).体外研究表明,这种同义突变会产生新的剪切位点,导致CYP17A1基因mRNA异常剪切,剪切产物中CYP17A1的415位氨基酸残基后缺失6或7个氨基酸.体外转染和酶活性检测证实异常剪切产物使酶活性丧失;但此突变对剪切的影响并不是完全的,在患者体内还应存在部分正常的剪切产物,发挥残余酶活性,与患者的表型相一致.结论 本研究首次报道了由于CYP17A1基因外显子剪切突变导致的17α-羟化酶缺乏的患者,并且启动对异常剪切体的功能研究.%Objective To analyze CYP17A1 gene mutation in a patient with 46,XY disordered sex development and to explore the possible influence on the phenotype of the patient.Methods Eight exons of CYP17AI gene in the patient and her parents were amplified and directly sequenced.In order to construct Mini-gene system,PCR fragments containing wildtype and mutant splicing sites were inserted in expression vector,and then transfected into cells.RT-PCR was used to observe the influence of splicing site mutation.Wildtype and aberrant splicing CYP17A1 cDNA expression plasmids were constructed and transfected into cells respectively,and CYP17A1 enzyme activity was tested in vitro.Results Mutation analysis revealed compound heterozygous

  3. CYP17A1基因新突变致17α-羟化酶/17,20-裂解酶部分性缺陷症%New compound heterozygous mutation causes partial combined 17α-hydroxylase/17,20-lyase deficiency

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    陶红; 张波; 陆召麟; 裴育; 米树华

    2007-01-01

    目的 研究1例17α-羟化酶/17,20-裂解酶部分性联合缺陷症患者CYP17A1基因突变特点,并结合患者的临床表现与基因突变类型初步探讨P450C17酶蛋白的结构与功能的关系.方法 收集1例17α-羟化酶/17,20-裂解酶部分性联合缺陷症患者的临床资料及其亲属血标本,提取基因组DNA,设计7对引物扩增CYP17A1基因的8个外显子及外显子与内含子的连接区域,琼脂糖凝胶电泳鉴定PCR产物,产物胶回收后直接做为DNA双链模板测序.DNA双链模板不一致的PCR产物经克隆后测序.测序结果在核苷酸序列数据库进行比较分析.结果 患者CYP17A1基因突变检测结果为5994-5995 delAT/7541 C>T复合杂合子.这两种突变均未见报道.推测5994-5995 delAT导致I259H,274X,突变形成的截短蛋白质缺少血红素结合区域,因此是没有功能的;而通过人类P450C17酶计算机模型分析显示7541 C>T导致的A398V远离酶的活性中心,推测突变可能使酶的活性减弱,而不是完全地丧失.患者临床表现为有自发不规则月经及轻度高血压、低血钾,结合激素测定结果提示肾上腺和性腺保留部分功能.因而患者的基因型与其临床表型是一致的.结论 应进行突变P450C17酶的功能学研究来进一步明确结构改变对功能的影响.

  4. A compound heterozwous mutation in CYP17A1 gene in a female subject with partial 17α-hydroxylase/17,20 lyase deficiency%复合杂合突变致部分性17α-羟化酶/17,20碳链裂解酶缺陷症的临床和遗传分析

    Institute of Scientific and Technical Information of China (English)

    姜艳; 张妲; 聂敏; 肖新华; 郁琦; 陆召麟

    2011-01-01

    Objective To explore the clinical and molecular genetic characteristics of a Chinese female patient with partial 17α- hydroxylase/17, 20 lyase deficiency ( 17OHD), a rare type of congenital adrenal hyperplasia. Methods Her clinical features and laboratory data were collected. Genomic DNA was extracted from leukocytes of peripheral blood of her and her mother. All eight exons of CYP17A1 gene,including flanking regions of introns, were amplified by PCR. The mutations of CYP17A1 gene were identified by direct sequencing or cloning and sequencing the amplified DNA fragments. Results The patient presented with hypertension, hypokalemia and irregular menstruation. DNA sequencing results demonstrated a compound heterozygous mutation in CYP17A1 gene. One allele of her had the deletion of phenylalanine (TTC) at either codon 53 or 54 and the other allele contained a base transversion at codon 329 (TAC/AA) and leading to a missense mutation of tyrosine to lysine and the open reading frame shift following this codon to produce a truncated enzyme with 417 amino acids and without activity site. Her mother was a heterozygous carrier of the latter allele. Conclusion The partial 17OHD in this patient is caused by a compound heterozygous mutation in CYP17A1 gene.%目的 通过对1例部分性17α-羟化酶/17,20碳链裂解酶缺陷症(17OHD)的女性患者及其母亲的临床特点和基因突变研究,初步探讨部分性17OHD患者临床表现的基因分子生物学机制。方法 收集患者临床资料,提取患者及其母亲的外周血白细胞DNA,PCR扩增CYP17A1基因的8个外显子及内含子边界,测序确定CYP17A1基因的突变位点。结果 患者临床表现为高血压及轻度低钾血症,有不规律月经,CYP17A1基因序列分析发现患者为复合杂合突变,其中1个等位基因突变为编码P45Oc17蛋白的53或54位苯丙氨酸的密码子TTC缺失,即Delp. 53/54F;另1个等位基因突变为编码329位氨基酸的密码子

  5. Comparisons of Prostate Cancer Inhibitors Abiraterone and TOK-001 Binding with CYP17A1 through Molecular Dynamics

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    Fei Xiao

    2015-01-01

    However, biology-driven inhibitor development of prostate cancer is poorly elucidated. The aims of this study are to address structural differences at atomic-level between CYP17A1 and inhibitors i.e., abiraterone and TOK-001, and further investigate the effect of point mutation of CYP17A1 on the active site stability and the local interactions that are hydrophobic interaction and hydrogen bonding throughout molecular dynamics (MD simulation. After performing multiple comparisons among four different complexes across CYP17A1 and inhibitors, interestingly TOK-001 oriented toward the active pocket and formed larger volume with I-helix of CYP17A1 than abiraterone, whereas abiraterone showed tighter binding and more active site stability. Considering on the effect of hydrophobic interaction and hydrogen bonding between abiraterone and CYP17A1, the key residues of Phe114, Ile371, Val482, and Asn202 were identified. This contributes into tight binding interactions; however abiraterone is effectively weakened along with the global conformation mobility increased in A105L mutation. Surprisingly, overall conformation of the CYP17A1 remained stable when bound to TOK-001. This basic knowledge can guide future experiments on design of efficient inhibitors for CYP17A1, which provides theoretical basis of androgen-dependent disease therapy.

  6. CYP17A1: a biochemistry, chemistry, and clinical review.

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    Porubek, David

    2013-01-01

    Cytochrome P450 17A1 (CYP17A1; also P450c17and P450sccII) is a critically important enzyme in humans that catalyzes the formation of all endogenous androgens. It is an atypical cytochrome P450 enzyme in that it catalyzes two distinct types of substrate oxidation. Through its hydroxylase activity, it catalyzes the 17α-hydroxylation of pregnenolone to 17α-OH pregnenolone. Subsequently, through its C17,20lyase activity, it can further convert 17α-OH pregnenolone to the androgen dehydroepiandrosterone, which is a precursor to androstenedione, testosterone, and dihydrotestosterone. The importance of androgens in diseases such as prostate cancer has been appreciated for decades and the discovery of extra-testicular formation of androgens has helped clarify the pathology of the disease, especially the castrate- resistant disease. Therefore, specific inhibition of CYP17A1 by therapeutic intervention has been an area of considerable effort in several research laboratories. This basic research has led to the discovery of several promising drug candidates followed by the conduct of several clinical trials. Recently, all these efforts have culminated in the first approval by FDA of an inhibitor of CYP17A1 for the treatment of castrate-resistant prostate cancer. Ongoing clinical trials are now evaluating the agent in earlier stages of prostate cancer and even rare forms of androgen-dependent breast cancer. Accordingly, this review focuses on the biochemistry, chemistry, and clinical inhibitors of CYP17A1.

  7. Active site proton delivery and the lyase activity of human CYP17A1

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    Khatri, Yogan; Gregory, Michael C.; Grinkova, Yelena V.; Denisov, Ilia G.; Sligar, Stephen G., E-mail: s-sligar@illinois.edu

    2014-01-03

    equivalents and protons are funneled into non-productive pathways. This is similar to previous work with other P450 catalyzed hydroxylation. However, catalysis of carbon–carbon bond scission by the T306A mutant was largely unimpeded by disruption of the CYP17A1 acid-alcohol pair. The unique response of CYP17A1 lyase activity to mutation of Thr306 is consistent with a reactive intermediate formed independently of proton delivery in the active site, and supports involvement of a nucleophilic peroxo-anion rather than the traditional Compound I in catalysis.

  8. Association between a common CYP17A1 haplotype and anxiety in female anorexia nervosa.

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    Czerniak, Efrat; Korostishevsky, Michael; Frisch, Amos; Cohen, Yoram; Amariglio, Ninette; Rechavi, Gideon; Michaelovsky, Elena; Stein, Daniel; Danziger, Yardena; Fennig, Silvana; Apter, Alan; Weizman, Abraham; Gak, Eva

    2013-10-01

    Dehydroepiandrosterone (DHEA), the main brain neurosteroid, has been implicated in various psychiatric disorders especially those including gender differences. We studied genetic variability in the DHEA-producing enzyme CYP17A1 in relation to anorexia nervosa (AN) susceptibility and AN-related co-morbidities. We performed analysis of 100 Israeli AN family trios accounting for CYP17A1 haplotypes characteristic of populations of European origin and studied genotype-phenotype relationships using correlation analyses and transmission disequilibrium test. Although our analysis revealed no evidence of association between CYP17A1 and AN per se, it revealed an association between specific CYP17A1 haplotypes and AN co-morbidity, specifically anxiety. We found that a common CYP17A1 haplotype (H1) was associated with higher anxiety in AN patients (Clinical Global Impression; CGI-anxiety ≥4). Moreover, H1 homozygotes were at higher risk for expressing high CGI-anxiety levels (OR = 3.7), and H1 was preferentially transmitted to AN patients with high CGI-anxiety levels (P = 0. 037). We suggest that CYP17A1 H1 haplotype may contribute to genetic predisposition to higher CGI-anxiety levels in AN patients and that this predisposition may be mediated by reduced CYP17A1 enzymatic activity and corresponding lower DHEA production.

  9. Hits identified in library screening demonstrate selective CYP17A1 lyase inhibition.

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    Krug, Sebastian J; Hu, Qingzhong; Hartmann, Rolf W

    2013-03-01

    A screening of structurally different steroid hormone synthesis inhibitors was performed in order to find a starting point for the development of a new inhibitor of the bifunctional steroidogenic enzyme CYP17A1. Emphasis was placed on determination of selectivity between the two catalytic steps, namely 17α-hydroxylase and C(17,20)-lyase. For that purpose a new inhibition assay has been developed. Hits identified within this novel assay demonstrated selective inhibition of CYP17A1 lyase activity, and thus mark the basis for the development of selective C(17,20)-lyase inhibitors for the treatment of prostate cancer.

  10. CYP17A1 and Blood Pressure Reactivity to Stress in Adolescence

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    Mariel Van Woudenberg

    2015-01-01

    Full Text Available Adolescents who exhibit exaggerated blood pressure (BP reactivity to physical and mental challenges are at increased risk of developing hypertension in adulthood. BP at rest and in response to challenges is higher in males than females, beginning in early adolescence. CYP17A1 is one of the well-established gene loci of adult hypertension. Here, we investigated whether this gene locus is associated with elevated BP at rest and in response to physical (active standing and mental (math stress challenges in adolescence. We studied 496 male and 532 female adolescents (age 12–18 years who were recruited from a genetic founder population. Our results showed that the variant of CYP17A1 rs10786718 was associated with enhanced BP reactivity to the mental but not physical challenge and in males but not females. In males, BP increase in response to math stress was higher in major versus minor allele homozygotes by 7.6 mm Hg (P=8.3×10-6. Resting BP was not associated with the CYP17A1 variant in either sex. These results suggest that, in adolescent males but not females, CYP17A1 enhances BP reactivity to mental stress. Whether this effect contributes to the higher prevalence of hypertension in males than females later in life remains to be determined.

  11. CYP17A1 and Blood Pressure Reactivity to Stress in Adolescence

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    Van Woudenberg, Mariel; Shin, Jean; Bernard, Manon; Syme, Catriona; Abrahamowicz, Michal; Leonard, Gabriel; Perron, Michel; Richer, Louis; Veillette, Suzanna; Gaudet, Daniel; Paus, Tomas; Pausova, Zdenka

    2015-01-01

    Adolescents who exhibit exaggerated blood pressure (BP) reactivity to physical and mental challenges are at increased risk of developing hypertension in adulthood. BP at rest and in response to challenges is higher in males than females, beginning in early adolescence. CYP17A1 is one of the well-established gene loci of adult hypertension. Here, we investigated whether this gene locus is associated with elevated BP at rest and in response to physical (active standing) and mental (math stress) challenges in adolescence. We studied 496 male and 532 female adolescents (age 12–18 years) who were recruited from a genetic founder population. Our results showed that the variant of CYP17A1 rs10786718 was associated with enhanced BP reactivity to the mental but not physical challenge and in males but not females. In males, BP increase in response to math stress was higher in major versus minor allele homozygotes by 7.6 mm Hg (P = 8.3 × 10−6). Resting BP was not associated with the CYP17A1 variant in either sex. These results suggest that, in adolescent males but not females, CYP17A1 enhances BP reactivity to mental stress. Whether this effect contributes to the higher prevalence of hypertension in males than females later in life remains to be determined. PMID:25692033

  12. Polymorphisms of CYP17A1, CYP19, and androgen in Brazilian women with uterine leiomyomas

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    Rosa, Fabíola Encinas; Canevari, Renata de Azevedo; Ambrosio, Eliane Papa;

    2008-01-01

    BACKGROUND: Uterine leiomyomas are common, benign, smooth muscle tumors representing a significant public health problem. The aim of this study was to investigate CYP17A1, CYP19, and androgen (AR) polymorphisms, their relative risks for uterine leiomyomas and possible associations with clinical p...... involved in steroidogenesis or steroid metabolism is consistent with the hypothesis that these polymorphisms do not substantially contribute to the development of these tumors....

  13. CYP17A1 Enzyme Activity Is Linked to Ambulatory Blood Pressure in a Family-Based Population Study.

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    Ackermann, Daniel; Pruijm, Menno; Ponte, Belen; Guessous, Idris; Ehret, Georg; Escher, Geneviève; Dick, Bernhard; Al-Alwan, Heba; Vuistiner, Philippe; Paccaud, Fred; Burnier, Michel; Péchère-Bertschi, Antoinette; Martin, Pierre-Yves; Vogt, Bruno; Mohaupt, Markus; Bochud, Murielle

    2016-04-01

    Genome-wide association studies have linked CYP17A1 coding for the steroid hormone synthesizing enzyme 17α-hydroxylase (CYP17A1) to blood pressure (BP). We hypothesized that the genetic signal may translate into a correlation of ambulatory BP (ABP) with apparent CYP17A1 activity in a family-based population study and estimated the heritability of CYP17A1 activity. In the Swiss Kidney Project on Genes in Hypertension, day and night urinary excretions of steroid hormone metabolites were measured in 518 participants (220 men, 298 women), randomly selected from the general population. CYP17A1 activity was assessed by 2 ratios of urinary steroid metabolites: one estimating the combined 17α-hydroxylase/17,20-lyase activity (ratio 1) and the other predominantly 17α-hydroxylase activity (ratio 2). A mixed linear model was used to investigate the association of ABP with log-transformed CYP17A1 activities exploring effect modification by urinary sodium excretion. Daytime ABP was positively associated with ratio 1 under conditions of high, but not low urinary sodium excretion (P interaction <0.05). Ratio 2 was not associated with ABP. Heritability estimates (SE) for day and night CYP17A1 activities were 0.39 (0.10) and 0.40 (0.09) for ratio 1, and 0.71 (0.09) and 0.55 (0.09) for ratio 2 (P values <0.001). CYP17A1 activities, assessed with ratio 1, were lower in older participants. Low apparent CYP17A1 activity (assessed with ratio 1) is associated with elevated daytime ABP when salt intake is high. CYP17A1 activity is heritable and diminished in the elderly. These observations highlight the modifying effect of salt intake on the association of CYP17A1 with BP. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Evidence that cytochrome b{sub 5} acts as a redox donor in CYP17A1 mediated androgen synthesis

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    Duggal, Ruchia [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Liu, Yilin [Department of Chemistry, Marquette University, Milwaukee, WI (United States); Gregory, Michael C.; Denisov, Ilia G. [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Kincaid, James R. [Department of Chemistry, Marquette University, Milwaukee, WI (United States); Sligar, Stephen G., E-mail: s-sligar@illinois.edu [Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States); Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL (United States)

    2016-08-19

    Cytochrome P450 17A1 (CYP17A1) is an important drug target for castration resistant prostate cancer. It is a bi-functional enzyme, catalyzing production of glucocorticoid precursors by hydroxylation of pregnene-nucleus, and androgen biosynthesis by a second C−C lyase step, at the expense of glucocorticoid production. Cytochrome b{sub 5} (cyt b{sub 5}) is known to be a key regulator of the androgen synthesis reaction in vivo, by a mechanism that is not well understood. Two hypotheses have been proposed for the mechanism by which cyt b{sub 5} increases androgen biosynthesis. Cyt b{sub 5} could act as an allosteric effector, binding to CYP17A1 and either changing its selective substrate affinity or altering the conformation of the P450 to increase the catalytic rate or decrease unproductive uncoupling channels. Alternatively, cyt b{sub 5} could act as a redox donor for supply of the second electron in the P450 cycle, reducing the oxyferrous complex to form the reactive peroxo-intermediate. To understand the mechanism of lyase enhancement by cyt b{sub 5}, we generated a redox-inactive form of cyt b{sub 5}, in which the heme is replaced with a Manganese-protoporphyrin IX (Mn-b{sub 5}), and investigated enhancement of androgen producing lyase reaction by CYP17A1. Given the critical significance of a stable membrane anchor for all of the proteins involved and the need for controlled stoichiometric ratios, we employed the Nanodisc system for this study. The redox inactive form was observed to have no effect on the lyase reaction, while reactions with the normal heme-iron containing cyt b{sub 5} were enhanced ∼5 fold as compared to reactions in the absence of cyt b{sub 5}. We also performed resonance Raman measurements on ferric CYP17A1 bound to Mn-b{sub 5}. Upon addition of Mn-b{sub 5} to Nanodisc reconstituted CYP17A1, we observed clear evidence for the formation of a b{sub 5}-CYP17A1 complex, as noted by changes in the porphyrin modes and alteration in the proximal

  15. Endurance exercise and conjugated linoleic acid (CLA supplementation up-regulate CYP17A1 and stimulate testosterone biosynthesis.

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    Rosario Barone

    Full Text Available A new role for fat supplements, in particular conjugated linoleic acid (CLA, has been delineated in steroidogenesis, although the underlying molecular mechanisms have not yet been elucidated. The aims of the present study were to identify the pathway stimulated by CLA supplementation using a cell culture model and to determine whether this same pathway is also stimulated in vivo by CLA supplementation associated with exercise. In vitro, Leydig tumour rat cells (R2C supplemented with different concentrations of CLA exhibited increasing testosterone biosynthesis accompanied by increasing levels of CYP17A1 mRNA and protein. In vivo, trained mice showed an increase in free plasma testosterone and an up-regulation of CYP17A1 mRNA and protein. The effect of training on CYP17A1 expression and testosterone biosynthesis was significantly higher in the trained mice supplemented with CLA compared to the placebo. The results of the present study demonstrated that CLA stimulates testosterone biosynthesis via CYP17A1, and endurance training led to the synthesis of testosterone in vivo by inducing the overexpression of CYP17A1 mRNA and protein in the Leydig cells of the testis. This effect was enhanced by CLA supplementation. Therefore, CLA-associated physical activity may be used for its steroidogenic property in different fields, such as alimentary industry, human reproductive medicine, sport science, and anti-muscle wasting.

  16. Endurance exercise and conjugated linoleic acid (CLA) supplementation up-regulate CYP17A1 and stimulate testosterone biosynthesis.

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    Barone, Rosario; Macaluso, Filippo; Catanese, Patrizia; Marino Gammazza, Antonella; Rizzuto, Luigi; Marozzi, Paola; Lo Giudice, Giuseppe; Stampone, Tomaso; Cappello, Francesco; Morici, Giuseppe; Zummo, Giovanni; Farina, Felicia; Di Felice, Valentina

    2013-01-01

    A new role for fat supplements, in particular conjugated linoleic acid (CLA), has been delineated in steroidogenesis, although the underlying molecular mechanisms have not yet been elucidated. The aims of the present study were to identify the pathway stimulated by CLA supplementation using a cell culture model and to determine whether this same pathway is also stimulated in vivo by CLA supplementation associated with exercise. In vitro, Leydig tumour rat cells (R2C) supplemented with different concentrations of CLA exhibited increasing testosterone biosynthesis accompanied by increasing levels of CYP17A1 mRNA and protein. In vivo, trained mice showed an increase in free plasma testosterone and an up-regulation of CYP17A1 mRNA and protein. The effect of training on CYP17A1 expression and testosterone biosynthesis was significantly higher in the trained mice supplemented with CLA compared to the placebo. The results of the present study demonstrated that CLA stimulates testosterone biosynthesis via CYP17A1, and endurance training led to the synthesis of testosterone in vivo by inducing the overexpression of CYP17A1 mRNA and protein in the Leydig cells of the testis. This effect was enhanced by CLA supplementation. Therefore, CLA-associated physical activity may be used for its steroidogenic property in different fields, such as alimentary industry, human reproductive medicine, sport science, and anti-muscle wasting.

  17. Discovery of the Selective CYP17A1 Lyase Inhibitor BMS-351 for the Treatment of Prostate Cancer.

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    Huang, Audris; Jayaraman, Lata; Fura, Aberra; Vite, Gregory D; Trainor, George L; Gottardis, Marco M; Spires, Thomas E; Spires, Vanessa M; Rizzo, Cheryl A; Obermeier, Mary T; Elzinga, Paul A; Todderud, Gordon; Fan, Yi; Newitt, John A; Beyer, Sophie M; Zhu, Yongxin; Warrack, Bethanne M; Goodenough, Angela K; Tebben, Andrew J; Doweyko, Arthur M; Gold, David L; Balog, Aaron

    2016-01-14

    Efforts to identify a potent, reversible, nonsteroidal CYP17A1 lyase inhibitor with good selectivity over CYP17A1 hydroxylase and CYPs 11B1 and 21A2 for the treatment of castration-resistant prostate cancer (CRPC) culminated in the discovery of BMS-351 (compound 18), a pyridyl biaryl benzimidazole with an excellent in vivo profile. Biological evaluation of BMS-351 at a dose of 1.5 mg in castrated cynomolgus monkeys revealed a remarkable reduction in testosterone levels with minimal glucocorticoid and mineralcorticoid perturbation. Based on a favorable profile, BMS-351 was selected as a candidate for further preclinical evaluation.

  18. Intratumoral de novo steroid synthesis activates androgen receptor in castration-resistant prostate cancer and is upregulated by treatment with CYP17A1 inhibitors.

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    Cai, Changmeng; Chen, Sen; Ng, Patrick; Bubley, Glenn J; Nelson, Peter S; Mostaghel, Elahe A; Marck, Brett; Matsumoto, Alvin M; Simon, Nicholas I; Wang, Hongyun; Chen, Shaoyong; Balk, Steven P

    2011-10-15

    Relapse of castration-resistant prostate cancer (CRPC) that occurs after androgen deprivation therapy of primary prostate cancer can be mediated by reactivation of the androgen receptor (AR). One important mechanism mediating this AR reactivation is intratumoral conversion of the weak adrenal androgens DHEA and androstenedione into the AR ligands testosterone and dihydrotestosterone. DHEA and androstenedione are synthesized by the adrenals through the sequential actions of the cytochrome P450 enzymes CYP11A1 and CYP17A1, so that CYP17A1 inhibitors such as abiraterone are effective therapies for CRPC. However, the significance of intratumoral CYP17A1 and de novo androgen synthesis from cholesterol in CRPC, and the mechanisms contributing to CYP17A1 inhibitor resistance/relapse, remain to be determined. We report that AR activity in castration-resistant VCaP tumor xenografts can be restored through CYP17A1-dependent de novo androgen synthesis, and that abiraterone treatment of these xenografts imposes selective pressure for increased intratumoral expression of CYP17A1, thereby generating a mechanism for development of resistance to CYP17A1 inhibitors. Supporting the clinical relevance of this mechanism, we found that intratumoral expression of CYP17A1 was markedly increased in tumor biopsies from CRPC patients after CYP17A1 inhibitor therapy. We further show that CRPC cells expressing a progesterone responsive T877A mutant AR are not CYP17A1 dependent, but that AR activity in these cells is still steroid dependent and mediated by upstream CYP11A1-dependent intraturmoral pregnenolone/progesterone synthesis. Together, our results indicate that CRPCs resistant to CYP17A1 inhibition may remain steroid dependent and therefore responsive to therapies that can further suppress de novo intratumoral steroid synthesis.

  19. Drospirenone intake alters plasmatic steroid levels and cyp17a1 expression in gonads of juvenile sea bass.

    Science.gov (United States)

    Blanco, Maria; Fernandes, Denise; Medina, Paula; Blázquez, Mercedes; Porte, Cinta

    2016-06-01

    Drospirenone (DRO) is one of the most widely used progestins in contraceptive treatments and hormone replacement therapies. The pharmacokinetics and potential toxicological effects of DRO were investigated in juvenile sea bass (Dicentrarchus labrax) exposed through the diet (0.01-10 μg DRO/g) for up to 31 days. DRO was detected in the blood (4-27 ng/mL) of fish exposed to the highest concentration, with no significant bioaccumulation over time and no alteration of hepatic metabolizing enzymes, namely, CYP1A and CYP3A-catalysed activities and UDP-glucuronyltransferase (UGT). Pregnenolone (P5), progesterone (P4), 17α-hydroxyprogesterone (17P4), 17α-hydroxypregnenolone (17P5), androstenedione (AD) and testosterone (T) were determined in plasma and gene expression of cyp17a1, cyp19a1a and cyp11β analysed by qRT-PCR in gonads. The significant increase in plasmatic levels of 17P5, 17P4 and AD detected after 31 days exposure to 10 ng DRO/g together with the increased expression of cyp17a1 in females evidence the ability of DRO to alter steroid synthesis at low intake concentrations (7 ng DRO/day). However, the potential consequences of this steroid shift for female reproduction remain to be investigated.

  20. Mechanistic Scrutiny Identifies a Kinetic Role for Cytochrome b5 Regulation of Human Cytochrome P450c17 (CYP17A1, P450 17A1)

    Science.gov (United States)

    Simonov, Alexandr N.; Holien, Jessica K.; Yeung, Joyee Chun In; Nguyen, Ann D.; Corbin, C. Jo; Zheng, Jie; Kuznetsov, Vladimir L.; Auchus, Richard J.; Conley, Alan J.; Bond, Alan M.; Parker, Michael W.; Rodgers, Raymond J.; Martin, Lisandra L.

    2015-01-01

    Cytochrome P450c17 (P450 17A1, CYP17A1) is a critical enzyme in the synthesis of androgens and is now a target enzyme for the treatment of prostate cancer. Cytochrome P450c17 can exhibit either one or two physiological enzymatic activities differentially regulated by cytochrome b5. How this is achieved remains unknown. Here, comprehensive in silico, in vivo and in vitro analyses were undertaken. Fluorescence Resonance Energy Transfer analysis showed close interactions within living cells between cytochrome P450c17 and cytochrome b5. In silico modeling identified the sites of interaction and confirmed that E48 and E49 residues in cytochrome b5 are essential for activity. Quartz crystal microbalance studies identified specific protein-protein interactions in a lipid membrane. Voltammetric analysis revealed that the wild type cytochrome b5, but not a mutated, E48G/E49G cyt b5, altered the kinetics of electron transfer between the electrode and the P450c17. We conclude that cytochrome b5 can influence the electronic conductivity of cytochrome P450c17 via allosteric, protein-protein interactions. PMID:26587646

  1. Mechanistic Scrutiny Identifies a Kinetic Role for Cytochrome b5 Regulation of Human Cytochrome P450c17 (CYP17A1, P450 17A1.

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    Alexandr N Simonov

    Full Text Available Cytochrome P450c17 (P450 17A1, CYP17A1 is a critical enzyme in the synthesis of androgens and is now a target enzyme for the treatment of prostate cancer. Cytochrome P450c17 can exhibit either one or two physiological enzymatic activities differentially regulated by cytochrome b5. How this is achieved remains unknown. Here, comprehensive in silico, in vivo and in vitro analyses were undertaken. Fluorescence Resonance Energy Transfer analysis showed close interactions within living cells between cytochrome P450c17 and cytochrome b5. In silico modeling identified the sites of interaction and confirmed that E48 and E49 residues in cytochrome b5 are essential for activity. Quartz crystal microbalance studies identified specific protein-protein interactions in a lipid membrane. Voltammetric analysis revealed that the wild type cytochrome b5, but not a mutated, E48G/E49G cyt b5, altered the kinetics of electron transfer between the electrode and the P450c17. We conclude that cytochrome b5 can influence the electronic conductivity of cytochrome P450c17 via allosteric, protein-protein interactions.

  2. Association between cytochrome CYP17A1, CYP3A4, and CYP3A43 polymorphisms and prostate cancer risk and aggressiveness in a Korean study population

    Directory of Open Access Journals (Sweden)

    Jun Hyun Han

    2015-04-01

    Full Text Available In this study, we evaluated genetic variants of the androgen metabolism genes CYP17A1, CYP3A4, and CYP3A43 to determine whether they play a role in the development of prostate cancer (PCa in Korean men. The study population included 240 pathologically diagnosed cases of PCa and 223 age-matched controls. Among the 789 single-nucleotide polymorphism (SNP database variants detected, 129 were reported in two Asian groups (Han Chinese and Japanese in the HapMap database. Only 21 polymorphisms of CYP17A1, CYP3A4, and CYP3A43 were selected based on linkage disequilibrium in Asians (r2 = 1, locations (SNPs in exons were preferred, and amino acid changes and were assessed. In addition, we performed haplotype analysis for the 21 SNPs in CYP17A1, CYP3A4, and CYP3A43 genes. To determine the association between genotype and haplotype distributions of patients and controls, logistic analyses were carried out, controlling for age. Twelve sequence variants and five major haplotypes were identified in CYP17A1. Five sequence variants and two major haplotypes were identified in CYP3A4. Four sequence variants and four major haplotypes were observed in CYP3A43. CYP17A1 haplotype-2 (Ht-2 (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.04-2.18 was associated with PCa susceptibility. CYP3A4 Ht-2 (OR: 1.87; 95% CI: 1.02-3.43 was associated with PCa metastatic potential according to tumor stage. rs17115149 (OR: 1.96; 95% CI: 1.04-3.68 and CYP17A1 Ht-4 (OR: 2.01; 95% CI: 1.07-4.11 showed a significant association with histologic aggressiveness according to Gleason score. Genetic variants of CYP17A1 and CYP3A4 may play a role in the development of PCa in Korean men.

  3. A Single Nucleotide Polymorphism near the CYP17A1 Gene Is Associated with Left Ventricular Mass in Hypertensive Patients under Pharmacotherapy

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    Matthias Huber

    2015-07-01

    Full Text Available Cytochrome P450 17A1 (CYP17A1 catalyses the formation and metabolism of steroid hormones. They are involved in blood pressure (BP regulation and in the pathogenesis of left ventricular hypertrophy. Therefore, altered function of CYP17A1 due to genetic variants may influence BP and left ventricular mass. Notably, genome wide association studies supported the role of this enzyme in BP control. Against this background, we investigated associations between single nucleotide polymorphisms (SNPs in or nearby the CYP17A1 gene with BP and left ventricular mass in patients with arterial hypertension and associated cardiovascular organ damage treated according to guidelines. Patients (n = 1007, mean age 58.0 ± 9.8 years, 83% men with arterial hypertension and cardiac left ventricular ejection fraction (LVEF ≥40% were enrolled in the study. Cardiac parameters of left ventricular mass, geometry and function were determined by echocardiography. The cohort comprised patients with coronary heart disease (n = 823; 81.7% and myocardial infarction (n = 545; 54.1% with a mean LVEF of 59.9% ± 9.3%. The mean left ventricular mass index (LVMI was 52.1 ± 21.2 g/m2.7 and 485 (48.2% patients had left ventricular hypertrophy. There was no significant association of any investigated SNP (rs619824, rs743572, rs1004467, rs11191548, rs17115100 with mean 24 h systolic or diastolic BP. However, carriers of the rs11191548 C allele demonstrated a 7% increase in LVMI (95% CI: 1%–12%, p = 0.017 compared to non-carriers. The CYP17A1 polymorphism rs11191548 demonstrated a significant association with LVMI in patients with arterial hypertension and preserved LVEF. Thus, CYP17A1 may contribute to cardiac hypertrophy in this clinical condition.

  4. The polymorphism (-600 C>A) of CpG methylation site at the promoter region of CYP17A1 and its association of male infertility and testosterone levels.

    Science.gov (United States)

    Park, Jung-Hoon; Lee, Jinu; Kim, Cheol-Hee; Lee, Suman

    2014-01-15

    Cytochrome P450, family 17, subfamily A, polypeptide 1 (CYP17A1) is a key regulatory enzyme in the steroidogenic pathway. The functional and clinical relevance of novel CYP17A1 promoter single nucleotide polymorphism (-600 C>A, rs17115149) was investigated with male infertility. Case-control association study of CYP17A1 from 456 infertile men performed with 465 normal fertile men. The rs17115149 at the promoter region of CYP17A1 was significantly associated with Oligoasthenoteratozoospermia (OAT, P=0.0015, n=265). 5-aza-dC treatment to B lymphocyte cells increased the CYP17A1 expression. Direct bisulfite sequencing of five human tissues showed that the rs17115149 is located at -600bp (-600C>A) before transcription start site within the CpG islands of CYP17A1 promoter. This -600 Cytosine of CpG site was highly methylated in colon and stomach tissues, but low methylated in adrenal gland, kidney and testis with higher CYP17A1 RNA expression. Especially, this polymorphism is statistically significant associated with testosterone levels from infertile males (n=197, PA) is a functional regulatory SNP which associated with its expression possibly by epigenetic pathway, which may signify a genetic risk factor for male infertility. © 2013 Elsevier B.V. All rights reserved.

  5. Identification and analysis of CYP7A1, CYP17A1, CYP20A1, CYP27A1 and CYP51A1 in cynomolgus macaques.

    Science.gov (United States)

    Uno, Yasuhiro; Hosaka, Shinya; Yamazaki, Hiroshi

    2014-12-01

    Cytochromes P450 (P450) are important for not only drug metabolism and toxicity, but also biosynthesis and metabolism of cholesterol and bile acids, and steroid synthesis. In cynomolgus macaques, widely used in biomedical research, we have characterized P450 cDNAs, which were isolated as expressed sequence tags of cynomolgus macaque liver. In this study, cynomolgus CYP7A1, CYP17A1, CYP20A1, CYP27A1 and CYP51A1 cDNAs were characterized by sequence analysis, phylogenetic analysis and tissue expression pattern. By sequence analysis, these five cynomolgus P450s had high sequence identities (94-99%) to the human orthologs in amino acids. By phylogenetic analysis, each cynomolgus P450 was more closely related to the human ortholog as compared with the dog or rat ortholog. By quantitative polymerase chain reaction, among the 10 tissue types, CYP7A1 and CYP17A1 mRNAs were preferentially expressed in liver and adrenal gland, respectively. Cynomolgus CYP27A1 and CYP51A1 mRNAs were most abundantly expressed in liver and testis, respectively. Cynomolgus CYP20A1 mRNA was expressed in all the tissues, including brain and liver. Tissue expression patterns of each cynomolgus P450 were generally similar to that of the human ortholog. These results suggest the molecular similarities of CYP7A1, CYP17A1, CYP20A1, CYP27A1 and CYP51A1 between cynomolgus macaques and humans.

  6. Polymorphisms in the cytochrome P450 genes CYP1A2, CYP1B1, CYP3A4, CYP3A5, CYP11A1, CYP17A1, CYP19A1 and colorectal cancer risk

    Directory of Open Access Journals (Sweden)

    Withey Laura

    2007-07-01

    Full Text Available Abstract Background Cytochrome P450 (CYP enzymes have the potential to affect colorectal cancer (CRC risk by determining the genotoxic impact of exogenous carcinogens and levels of sex hormones. Methods To investigate if common variants of CYP1A2, CYP1B1, CYP3A4, CYP3A5, CYP11A1, CYP17A1 and CYP19A1 influence CRC risk we genotyped 2,575 CRC cases and 2,707 controls for 20 single nucleotide polymorphisms (SNPs that have not previously been shown to have functional consequence within these genes. Results There was a suggestion of increased risk, albeit insignificant after correction for multiple testing, of CRC for individuals homozygous for CYP1B1 rs162558 and heterozygous for CYP1A2 rs2069522 (odds ratio [OR] = 1.36, 95% confidence interval [CI]: 1.03–1.80 and OR = 1.34, 95% CI: 1.00–1.79 respectively. Conclusion This study provides some support for polymorphic variation in CYP1A2 and CYP1B1 playing a role in CRC susceptibility.

  7. A cross-sectional study to assess any possible linkage of C/T polymorphism in CYP17A1 gene with insulin resistance in non-obese women with polycystic ovarian syndrome

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    Ushasi Banerjee

    2016-01-01

    Full Text Available Background & objectives: Insulin resistance (IR is a major confounding factor in polycystic ovarian syndrome (PCOS irrespective of obesity. Its exact mechanism remains elusive till now. C/T polymorphism in the -34 promoter region of the CYP17 gene is inconsistently attributed to elucidate the mechanism of IR and its link to hyperandrogenemia in obese PCOS patients. In the present study we aimed to evaluate any association of this polymorphism with IR in non-obese women with PCOS. Methods: Polymorphism study was performed by restriction fragment length polymorphism (RFLP analysis of the Msp A1 digest of the PCR product of the target gene in 75 PCOS cases against 73 age and BMI matched control women. Serum testosterone, BMI and HOMA-IR (homeostatic model of assessment-insulin resistance were analyzed by standard techniques. A realistic cut-off value for the HOMA-IR was obtained through receiver operating characteristic (ROC curve for exploring any possible link between IR and T/C polymorphism in the case group. Results: Significant increases in serum testosterone and HOMA-IR values were observed among the case group (P<0.001 without any significant elevation in BMI and FBG compared to controls. Cut-off value for IR in the PCOS patients was 1.40 against a maximum sensitivity of 0.83 and a minimum false positivity of 0.13. The analysis revealed an inconclusive link between the C/T polymorphic distribution and insulin resistant case subjects. Interpretation & conclusions: The results showed that CYP17A1 gene was not conclusively linked to either IR or its associated increased androgen secretion in non-obese women with PCOS. We propose that an increased sensitivity of insulin on the ovarian cells may be the predominant reason for the clinical effects and symptoms of androgen excess observed in non-obese PCOS patients in our region.

  8. Mutations in ANKH cause chondrocalcinosis.

    Science.gov (United States)

    Pendleton, Adrian; Johnson, Michelle D; Hughes, Anne; Gurley, Kyle A; Ho, Andrew M; Doherty, Michael; Dixey, Josh; Gillet, Pierre; Loeuille, Damien; McGrath, Rodney; Reginato, Antonio; Shiang, Rita; Wright, Gary; Netter, Patrick; Williams, Charlene; Kingsley, David M

    2002-10-01

    Chondrocalcinosis (CC) is a common cause of joint pain and arthritis that is caused by the deposition of calcium-containing crystals within articular cartilage. Although most cases are sporadic, rare familial forms have been linked to human chromosomes 8 (CCAL1) or 5p (CCAL2) (Baldwin et al. 1995; Hughes et al. 1995; Andrew et al. 1999). Here, we show that two previously described families with CCAL2 have mutations in the human homolog of the mouse progressive ankylosis gene (ANKH). One of the human mutations results in the substitution of a highly conserved amino acid residue within a predicted transmembrane segment. The other creates a new ATG start site that adds four additional residues to the ANKH protein. Both mutations segregate completely with disease status and are not found in control subjects. In addition, 1 of 95 U.K. patients with sporadic CC showed a deletion of a single codon in the ANKH gene. The same change was found in a sister who had bilateral knee replacement for osteoarthritis. Each of the three human mutations was reconstructed in a full-length ANK expression construct previously shown to regulate pyrophosphate levels in cultured cells in vitro. All three of the human mutations showed significantly more activity than a previously described nonsense mutation that causes severe hydroxyapatite mineral deposition and widespread joint ankylosis in mice. These results suggest that small sequence changes in ANKH are one cause of CC and joint disease in humans. Increased ANK activity may explain the different types of crystals commonly deposited in human CCAL2 families and mutant mice and may provide a useful pharmacological target for treating some forms of human CC.

  9. Mutations in RARS cause hypomyelination

    NARCIS (Netherlands)

    Wolf, Nicole I.; Salomons, Gajja S.; Rodenburg, Richard J.; Pouwels, Petra J. W.; Schieving, Jolanda H.; Derks, Terry G. J.; Fock, Johanna M.; Rump, Patrick; van Beek, Daphne M.; van der Knaap, Marjo S.; Waisfisz, Quinten

    2014-01-01

    Hypomyelinating disorders of the central nervous system are still a diagnostic challenge, as many patients remain without genetic diagnosis. Using magnetic resonance imaging (MRI) pattern recognition and whole exome sequencing, we could ascertain compound heterozygous mutations in RARS in 4 patients

  10. Mutations in RARS cause hypomyelination

    NARCIS (Netherlands)

    Wolf, Nicole I.; Salomons, Gajja S.; Rodenburg, Richard J.; Pouwels, Petra J. W.; Schieving, Jolanda H.; Derks, Terry G. J.; Fock, Johanna M.; Rump, Patrick; van Beek, Daphne M.; van der Knaap, Marjo S.; Waisfisz, Quinten

    Hypomyelinating disorders of the central nervous system are still a diagnostic challenge, as many patients remain without genetic diagnosis. Using magnetic resonance imaging (MRI) pattern recognition and whole exome sequencing, we could ascertain compound heterozygous mutations in RARS in 4 patients

  11. Mutations in RARS cause hypomyelination

    NARCIS (Netherlands)

    Wolf, N.I.; Salomons, G.S.; Rodenburg, R.J.; Pouwels, P.J.; Schieving, J.H.; Derks, T.G.; Fock, J.M.; Rump, P.; Beek, D.M. van; Knaap, M.S. van der; Waisfisz, Q.

    2014-01-01

    Hypomyelinating disorders of the central nervous system are still a diagnostic challenge, as many patients remain without genetic diagnosis. Using magnetic resonance imaging (MRI) pattern recognition and whole exome sequencing, we could ascertain compound heterozygous mutations in RARS in 4 patients

  12. Mutations in ANTXR1 Cause GAPO Syndrome

    NARCIS (Netherlands)

    Stranecky, V.; Hoischen, A.; Hartmannova, H.; Zaki, M.S.; Chaudhary, A.; Zudaire, E.; Noskova, L.; Baresova, V.; Pristoupilova, A.; Hodanova, K.; Sovova, J.; Hulkova, H.; Piherova, L.; Hehir-Kwa, J.Y.; Silva, D. De; Senanayake, M.P.; Farrag, S.; Zeman, J.; Martasek, P.; Baxova, A.; Afifi, H.H.; Croix, B. St.; Brunner, H.G.; Temtamy, S.; Kmoch, S.

    2013-01-01

    The genetic cause of GAPO syndrome, a condition characterized by growth retardation, alopecia, pseudoanodontia, and progressive visual impairment, has not previously been identified. We studied four ethnically unrelated affected individuals and identified homozygous nonsense mutations (c.262C>T [

  13. Inherited cardiomyopathies caused by troponin mutations

    Institute of Scientific and Technical Information of China (English)

    Qun-Wei Lu; Xiao-Yan Wu; Sachio Morimoto

    2013-01-01

    Genetic investigations of cardiomyopathy in the recent two decades have revealed a large number of mutations in the genes encoding sarcomeric proteins as a cause of inherited hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), or restrictive cardiomyopathy (RCM). Most functional analyses of the effects of mutations on cardiac muscle contraction have revealed significant changes in the Ca2+-regulatory mechanism, in which cardiac troponin (cTn) plays important structural and functional roles as a key regulatory protein. Over a hundred mutations have been identified in all three subunits of cTn, i.e., cardiac troponins T, I, and C. Recent studies on cTn mutations have provided plenty of evidence that HCM- and RCM-linked mutations increase cardiac myofilament Ca2+ sensitivity, while DCM-linked mutations decrease it. This review focuses on the functional consequences of mutations found in cTn in terms of cardiac myofilament Ca2+ sensitivity, ATPase activity, force generation, and cardiac troponin I phosphorylation, to understand potential molecular and cellular pathogenic mechanisms of the three types of inherited cardiomyopathy.

  14. ACTN1 mutations cause congenital macrothrombocytopenia.

    Science.gov (United States)

    Kunishima, Shinji; Okuno, Yusuke; Yoshida, Kenichi; Shiraishi, Yuichi; Sanada, Masashi; Muramatsu, Hideki; Chiba, Kenichi; Tanaka, Hiroko; Miyazaki, Koji; Sakai, Michio; Ohtake, Masatoshi; Kobayashi, Ryoji; Iguchi, Akihiro; Niimi, Gen; Otsu, Makoto; Takahashi, Yoshiyuki; Miyano, Satoru; Saito, Hidehiko; Kojima, Seiji; Ogawa, Seishi

    2013-03-01

    Congenital macrothrombocytopenia (CMTP) is a heterogeneous group of rare platelet disorders characterized by a congenital reduction of platelet counts and abnormally large platelets, for which CMTP-causing mutations are only found in approximately half the cases. We herein performed whole-exome sequencing and targeted Sanger sequencing to identify mutations that cause CMTP, in which a dominant mode of transmission had been suspected but for which no known responsible mutations have been documented. In 13 Japanese CMTP-affected pedigrees, we identified six (46%) affected by ACTN1 variants cosegregating with CMTP. In the entire cohort, ACNT1 variants accounted for 5.5% of the dominant forms of CMTP cases and represented the fourth most common cause in Japanese individuals. Individuals with ACTN1 variants presented with moderate macrothrombocytopenia with anisocytosis but were either asymptomatic or had only a modest bleeding tendency. ACTN1 encodes α-actinin-1, a member of the actin-crosslinking protein superfamily that participates in the organization of the cytoskeleton. In vitro transfection experiments in Chinese hamster ovary cells demonstrated that altered α-actinin-1 disrupted the normal actin-based cytoskeletal structure. Moreover, transduction of mouse fetal liver-derived megakaryocytes with disease-associated ACTN1 variants caused a disorganized actin-based cytoskeleton in megakaryocytes, resulting in the production of abnormally large proplatelet tips, which were reduced in number. Our findings provide an insight into the pathogenesis of CMTP.

  15. Mutations in XRCC4 cause primordial dwarfism without causing immunodeficiency.

    Science.gov (United States)

    Saito, Shinta; Kurosawa, Aya; Adachi, Noritaka

    2016-08-01

    In successive reports from 2014 to 2015, X-ray repair cross-complementing protein 4 (XRCC4) has been identified as a novel causative gene of primordial dwarfism. XRCC4 is indispensable for non-homologous end joining (NHEJ), the major pathway for repairing DNA double-strand breaks. As NHEJ is essential for V(D)J recombination during lymphocyte development, it is generally believed that abnormalities in XRCC4 cause severe combined immunodeficiency. Contrary to expectations, however, no overt immunodeficiency has been observed in patients with primordial dwarfism harboring XRCC4 mutations. Here, we describe the various XRCC4 mutations that lead to disease and discuss their impact on NHEJ and V(D)J recombination.

  16. FAT1 mutations cause a glomerulotubular nephropathy

    Science.gov (United States)

    Gee, Heon Yung; Sadowski, Carolin E.; Aggarwal, Pardeep K.; Porath, Jonathan D.; Yakulov, Toma A.; Schueler, Markus; Lovric, Svjetlana; Ashraf, Shazia; Braun, Daniela A.; Halbritter, Jan; Fang, Humphrey; Airik, Rannar; Vega-Warner, Virginia; Cho, Kyeong Jee; Chan, Timothy A.; Morris, Luc G. T.; ffrench-Constant, Charles; Allen, Nicholas; McNeill, Helen; Büscher, Rainer; Kyrieleis, Henriette; Wallot, Michael; Gaspert, Ariana; Kistler, Thomas; Milford, David V.; Saleem, Moin A.; Keng, Wee Teik; Alexander, Stephen I.; Valentini, Rudolph P.; Licht, Christoph; Teh, Jun C.; Bogdanovic, Radovan; Koziell, Ania; Bierzynska, Agnieszka; Soliman, Neveen A.; Otto, Edgar A.; Lifton, Richard P.; Holzman, Lawrence B.; Sibinga, Nicholas E. S.; Walz, Gerd; Tufro, Alda; Hildebrandt, Friedhelm

    2016-01-01

    Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function. PMID:26905694

  17. RPGR mutations might cause reduced orientation of respiratory cilia

    NARCIS (Netherlands)

    Bukowy-Bieryllo, Zuzanna; Zietkiewicz, Ewa; Loges, Niki Tomas; Wittmer, Mariana; Geremek, Maciej; Olbrich, Heike; Fliegauf, Manfred; Voelkel, Katarzyna; Rutkiewicz, Ewa; Rutland, Jonathan; Morgan, Lucy; Pogorzelski, Andrzej; Martin, James; Haan, Eric; Berger, Wolfgang; Omran, Heymut; Witt, Michal

    2013-01-01

    RPGR gene encodes retinitis pigmentosa guanosine triphosphatase regulator protein, mutations of which cause 70% of the X-linked retinitis pigmentosa (XLRP) cases. Rarely, RPGR mutations can also cause primary ciliary dyskinesia (PCD), a multisystem disorder characterized by recurrent respiratory tra

  18. Frontotemporal dementia caused by CHMP2B mutations

    DEFF Research Database (Denmark)

    Isaacs, A M; Johannsen, P; Holm, I;

    2011-01-01

    CHMP2B mutations are a rare cause of autosomal dominant frontotemporal dementia (FTD). The best studied example is frontotemporal dementia linked to chromosome 3 (FTD-3) which occurs in a large Danish family, with a further CHMP2B mutation identified in an unrelated Belgian familial FTD patient. ...... features of FTD caused by CHMP2B truncation mutations as well as new brain imaging and neuropathological findings. Finally, we collate the current data on CHMP2B missense mutations, which have been reported in FTD and motor neuron disease....

  19. ELOVL5 Mutations Cause Spinocerebellar Ataxia 38

    Science.gov (United States)

    Di Gregorio, Eleonora; Borroni, Barbara; Giorgio, Elisa; Lacerenza, Daniela; Ferrero, Marta; Lo Buono, Nicola; Ragusa, Neftj; Mancini, Cecilia; Gaussen, Marion; Calcia, Alessandro; Mitro, Nico; Hoxha, Eriola; Mura, Isabella; Coviello, Domenico A.; Moon, Young-Ah; Tesson, Christelle; Vaula, Giovanna; Couarch, Philippe; Orsi, Laura; Duregon, Eleonora; Papotti, Mauro Giulio; Deleuze, Jean-François; Imbert, Jean; Costanzi, Chiara; Padovani, Alessandro; Giunti, Paola; Maillet-Vioud, Marcel; Durr, Alexandra; Brice, Alexis; Tempia, Filippo; Funaro, Ada; Boccone, Loredana; Caruso, Donatella; Stevanin, Giovanni; Brusco, Alfredo

    2014-01-01

    Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal-dominant neurodegenerative disorders involving the cerebellum and 23 different genes. We mapped SCA38 to a 56 Mb region on chromosome 6p in a SCA-affected Italian family by whole-genome linkage analysis. Targeted resequencing identified a single missense mutation (c.689G>T [p.Gly230Val]) in ELOVL5. Mutation screening of 456 independent SCA-affected individuals identified the same mutation in two further unrelated Italian families. Haplotyping showed that at least two of the three families shared a common ancestor. One further missense variant (c.214C>G [p.Leu72Val]) was found in a French family. Both missense changes affect conserved amino acids, are predicted to be damaging by multiple bioinformatics tools, and were not identified in ethnically matched controls or within variant databases. ELOVL5 encodes an elongase involved in the synthesis of polyunsaturated fatty acids of the ω3 and ω6 series. Arachidonic acid and docosahexaenoic acid, two final products of the enzyme, were reduced in the serum of affected individuals. Immunohistochemistry on control mice and human brain demonstrated high levels in Purkinje cells. In transfection experiments, subcellular localization of altered ELOVL5 showed a perinuclear distribution with a signal increase in the Golgi compartment, whereas the wild-type showed a widespread signal in the endoplasmic reticulum. SCA38 and SCA34 are examples of SCAs due to mutations in elongase-encoding genes, emphasizing the importance of fatty-acid metabolism in neurological diseases. PMID:25065913

  20. ELOVL5 mutations cause spinocerebellar ataxia 38.

    Science.gov (United States)

    Di Gregorio, Eleonora; Borroni, Barbara; Giorgio, Elisa; Lacerenza, Daniela; Ferrero, Marta; Lo Buono, Nicola; Ragusa, Neftj; Mancini, Cecilia; Gaussen, Marion; Calcia, Alessandro; Mitro, Nico; Hoxha, Eriola; Mura, Isabella; Coviello, Domenico A; Moon, Young-Ah; Tesson, Christelle; Vaula, Giovanna; Couarch, Philippe; Orsi, Laura; Duregon, Eleonora; Papotti, Mauro Giulio; Deleuze, Jean-François; Imbert, Jean; Costanzi, Chiara; Padovani, Alessandro; Giunti, Paola; Maillet-Vioud, Marcel; Durr, Alexandra; Brice, Alexis; Tempia, Filippo; Funaro, Ada; Boccone, Loredana; Caruso, Donatella; Stevanin, Giovanni; Brusco, Alfredo

    2014-08-07

    Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal-dominant neurodegenerative disorders involving the cerebellum and 23 different genes. We mapped SCA38 to a 56 Mb region on chromosome 6p in a SCA-affected Italian family by whole-genome linkage analysis. Targeted resequencing identified a single missense mutation (c.689G>T [p.Gly230Val]) in ELOVL5. Mutation screening of 456 independent SCA-affected individuals identified the same mutation in two further unrelated Italian families. Haplotyping showed that at least two of the three families shared a common ancestor. One further missense variant (c.214C>G [p.Leu72Val]) was found in a French family. Both missense changes affect conserved amino acids, are predicted to be damaging by multiple bioinformatics tools, and were not identified in ethnically matched controls or within variant databases. ELOVL5 encodes an elongase involved in the synthesis of polyunsaturated fatty acids of the ω3 and ω6 series. Arachidonic acid and docosahexaenoic acid, two final products of the enzyme, were reduced in the serum of affected individuals. Immunohistochemistry on control mice and human brain demonstrated high levels in Purkinje cells. In transfection experiments, subcellular localization of altered ELOVL5 showed a perinuclear distribution with a signal increase in the Golgi compartment, whereas the wild-type showed a widespread signal in the endoplasmic reticulum. SCA38 and SCA34 are examples of SCAs due to mutations in elongase-encoding genes, emphasizing the importance of fatty-acid metabolism in neurological diseases.

  1. Dihydropyridine receptor mutations cause hypokalemic periodic paralysis

    Energy Technology Data Exchange (ETDEWEB)

    Ptacek, L.J.; Leppert, M.F. [Univ. of Utah, Salt Lake City, UT (United States); Tawil, R. [Univ. of Rochester, MN (United States)] [and others

    1994-09-01

    Hypokalemic periodic paralysis (hypoKPP) is an autosomal dominant skeletal muscle disorder manifested by episodic weakness associated with low serum potassium. Genetic linkage analysis has localized the hypoKPP gene to chromosome 1q31-q32 near a dihydropyridine receptor (DHP) gene. This receptor functions as a voltage-gated calcium channel and is also critical for excitation-contraction coupling in a voltage-sensitive and calcium-independent manner. We have characterized patient-specific DHP receptor mutations in 11 probands of 33 independent hypoKPP kindreds that occur at one of two adjacent nucleotides within the same codon and predict substitution of a highly conserved arginine in the S4 segment of domain 4 with either histidine or glycine. In one kindred, the mutation arose de novo. Taken together, these data establish the DHP receptor as the hypoKPP gene. We are unaware of any other human diseases presently known to result from DHP receptor mutations.

  2. Mutations in ZBTB20 cause Primrose syndrome.

    Science.gov (United States)

    Cordeddu, Viviana; Redeker, Bert; Stellacci, Emilia; Jongejan, Aldo; Fragale, Alessandra; Bradley, Ted E J; Anselmi, Massimiliano; Ciolfi, Andrea; Cecchetti, Serena; Muto, Valentina; Bernardini, Laura; Azage, Meron; Carvalho, Daniel R; Espay, Alberto J; Male, Alison; Molin, Anna-Maja; Posmyk, Renata; Battisti, Carla; Casertano, Alberto; Melis, Daniela; van Kampen, Antoine; Baas, Frank; Mannens, Marcel M; Bocchinfuso, Gianfranco; Stella, Lorenzo; Tartaglia, Marco; Hennekam, Raoul C

    2014-08-01

    Primrose syndrome and 3q13.31 microdeletion syndrome are clinically related disorders characterized by tall stature, macrocephaly, intellectual disability, disturbed behavior and unusual facial features, with diabetes, deafness, progressive muscle wasting and ectopic calcifications specifically occurring in the former. We report that missense mutations in ZBTB20, residing within the 3q13.31 microdeletion syndrome critical region, underlie Primrose syndrome. This finding establishes a genetic link between these disorders and delineates the impact of ZBTB20 dysregulation on development, growth and metabolism.

  3. Disease causing mutations of calcium channels.

    Science.gov (United States)

    Lorenzon, Nancy M; Beam, Kurt G

    2008-01-01

    Calcium ions play an important role in the electrical excitability of nerve and muscle, as well as serving as a critical second messenger for diverse cellular functions. As a result, mutations of genes encoding calcium channels may have subtle affects on channel function yet strongly perturb cellular behavior. This review discusses the effects of calcium channel mutations on channel function, the pathological consequences for cellular physiology, and possible links between altered channel function and disease. Many cellular functions are directly or indirectly regulated by the free cytosolic calcium concentration. Thus, calcium levels must be very tightly regulated in time and space. Intracellular calcium ions are essential second messengers and play a role in many functions including, action potential generation, neurotransmitter and hormone release, muscle contraction, neurite outgrowth, synaptogenesis, calcium-dependent gene expression, synaptic plasticity and cell death. Calcium ions that control cell activity can be supplied to the cell cytosol from two major sources: the extracellular space or intracellular stores. Voltage-gated and ligand-gated channels are the primary way in which Ca(2+) ions enter from the extracellular space. The sarcoplasm reticulum (SR) in muscle and the endoplasmic reticulum in non-muscle cells are the main intracellular Ca(2+) stores: the ryanodine receptor (RyR) and inositol-triphosphate receptor channels are the major contributors of calcium release from internal stores.

  4. Human NR5A1/SF-1 mutations show decreased activity on BDNF (brain-derived neurotrophic factor), an important regulator of energy balance: testing impact of novel SF-1 mutations beyond steroidogenesis.

    Science.gov (United States)

    Malikova, Jana; Camats, Núria; Fernández-Cancio, Mónica; Heath, Karen; González, Isabel; Caimarí, María; del Campo, Miguel; Albisu, Marian; Kolouskova, Stanislava; Audí, Laura; Flück, Christa E

    2014-01-01

    Human NR5A1/SF-1 mutations cause 46,XY disorder of sex development (DSD) with broad phenotypic variability, and rarely cause adrenal insufficiency although SF-1 is an important transcription factor for many genes involved in steroidogenesis. In addition, the Sf-1 knockout mouse develops obesity with age. Obesity might be mediated through Sf-1 regulating activity of brain-derived neurotrophic factor (BDNF), an important regulator of energy balance in the ventromedial hypothalamus. To characterize novel SF-1 gene variants in 4 families, clinical, genetic and functional studies were performed with respect to steroidogenesis and energy balance. 5 patients with 46,XY DSD were found to harbor NR5A1/SF-1 mutations including 2 novel variations. One patient harboring a novel mutation also suffered from adrenal insufficiency. SF-1 mutations were studied in cell systems (HEK293, JEG3) for impact on transcription of genes involved in steroidogenesis (CYP11A1, CYP17A1, HSD3B2) and in energy balance (BDNF). BDNF regulation by SF-1 was studied by promoter assays (JEG3). Two novel NR5A1/SF-1 mutations (Glu7Stop, His408Profs*159) were confirmed. Glu7Stop is the 4th reported SF-1 mutation causing DSD and adrenal insufficiency. In vitro studies revealed that transcription of the BDNF gene is regulated by SF-1, and that mutant SF-1 decreased BDNF promoter activation (similar to steroid enzyme promoters). However, clinical data from 16 subjects carrying SF-1 mutations showed normal birth weight and BMI. Glu7Stop and His408Profs*159 are novel SF-1 mutations identified in patients with 46,XY DSD and adrenal insufficiency (Glu7Stop). In vitro, SF-1 mutations affect not only steroidogenesis but also transcription of BDNF which is involved in energy balance. However, in contrast to mice, consequences on weight were not found in humans with SF-1 mutations.

  5. Human NR5A1/SF-1 mutations show decreased activity on BDNF (brain-derived neurotrophic factor, an important regulator of energy balance: testing impact of novel SF-1 mutations beyond steroidogenesis.

    Directory of Open Access Journals (Sweden)

    Jana Malikova

    Full Text Available Human NR5A1/SF-1 mutations cause 46,XY disorder of sex development (DSD with broad phenotypic variability, and rarely cause adrenal insufficiency although SF-1 is an important transcription factor for many genes involved in steroidogenesis. In addition, the Sf-1 knockout mouse develops obesity with age. Obesity might be mediated through Sf-1 regulating activity of brain-derived neurotrophic factor (BDNF, an important regulator of energy balance in the ventromedial hypothalamus.To characterize novel SF-1 gene variants in 4 families, clinical, genetic and functional studies were performed with respect to steroidogenesis and energy balance.5 patients with 46,XY DSD were found to harbor NR5A1/SF-1 mutations including 2 novel variations. One patient harboring a novel mutation also suffered from adrenal insufficiency.SF-1 mutations were studied in cell systems (HEK293, JEG3 for impact on transcription of genes involved in steroidogenesis (CYP11A1, CYP17A1, HSD3B2 and in energy balance (BDNF. BDNF regulation by SF-1 was studied by promoter assays (JEG3.Two novel NR5A1/SF-1 mutations (Glu7Stop, His408Profs*159 were confirmed. Glu7Stop is the 4th reported SF-1 mutation causing DSD and adrenal insufficiency. In vitro studies revealed that transcription of the BDNF gene is regulated by SF-1, and that mutant SF-1 decreased BDNF promoter activation (similar to steroid enzyme promoters. However, clinical data from 16 subjects carrying SF-1 mutations showed normal birth weight and BMI.Glu7Stop and His408Profs*159 are novel SF-1 mutations identified in patients with 46,XY DSD and adrenal insufficiency (Glu7Stop. In vitro, SF-1 mutations affect not only steroidogenesis but also transcription of BDNF which is involved in energy balance. However, in contrast to mice, consequences on weight were not found in humans with SF-1 mutations.

  6. Frontotemporal dementia caused by CHMP2B mutations

    DEFF Research Database (Denmark)

    Isaacs, A M; Johannsen, P; Holm, I

    2011-01-01

    CHMP2B mutations are a rare cause of autosomal dominant frontotemporal dementia (FTD). The best studied example is frontotemporal dementia linked to chromosome 3 (FTD-3) which occurs in a large Danish family, with a further CHMP2B mutation identified in an unrelated Belgian familial FTD patient....... These mutations lead to C-terminal truncations of the CHMP2B protein and we will review recent advances in our understanding of the molecular effects of these mutant truncated proteins on vesicular fusion events within the endosome-lysosome and autophagy degradation pathways. We will also review the clinical...... features of FTD caused by CHMP2B truncation mutations as well as new brain imaging and neuropathological findings. Finally, we collate the current data on CHMP2B missense mutations, which have been reported in FTD and motor neuron disease....

  7. Intronic splicing mutations in PTCH1 cause Gorlin syndrome.

    Science.gov (United States)

    Bholah, Zaynab; Smith, Miriam J; Byers, Helen J; Miles, Emma K; Evans, D Gareth; Newman, William G

    2014-09-01

    Gorlin syndrome is an autosomal dominant disorder characterized by multiple early-onset basal cell carcinoma, odontogenic keratocysts and skeletal abnormalities. It is caused by heterozygous mutations in the tumour suppressor PTCH1. Routine clinical genetic testing, by Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to confirm a clinical diagnosis of Gorlin syndrome, identifies a mutation in 60-90 % of cases. We undertook RNA analysis on lymphocytes from ten individuals diagnosed with Gorlin syndrome, but without known PTCH1 mutations by exonic sequencing or MLPA. Two altered PTCH1 transcripts were identified. Genomic DNA sequence analysis identified an intron 7 mutation c.1068-10T>A, which created a strong cryptic splice acceptor site, leading to an intronic insertion of eight bases; this is predicted to create a frameshift p.(His358Alafs*12). Secondly, a deep intronic mutation c.2561-2057A>G caused an inframe insertion of 78 intronic bases in the cDNA transcript, leading to a premature stop codon p.(Gly854fs*3). The mutations are predicted to cause loss of function of PTCH1, consistent with its tumour suppressor function. The findings indicate the importance of RNA analysis to detect intronic mutations in PTCH1 not identified by routine screening techniques.

  8. Overlapping DSPP mutations cause dentin dysplasia and dentinogenesis imperfecta.

    Science.gov (United States)

    McKnight, D A; Simmer, J P; Hart, P S; Hart, T C; Fisher, L W

    2008-12-01

    Dentinogenesis imperfecta (DGI) and dentin dysplasia (DD) are allelic disorders due to mutations in DSPP. Typically, the phenotype breeds true within a family. Recently, two reports showed that 3 different net -1 bp frameshift mutations early in DSPP's repeat domain caused DD, whereas 6 more 3' frameshift mutations were associated with DGI. Here we identify a DD kindred with a novel -1 bp frameshift (c.3141delC) that falls within the portion of the DSPP repeat domain previously associated solely with the DGI phenotype. This new frameshift mutation shows that overlapping DSPP mutations can give rise to either DGI or DD phenotypes. Furthermore, the consistent kindred presentation of the DD or DGI phenotype appears to be dependent on an as-yet-undescribed genetic modifier closely linked to DSPP.

  9. Simple method for detection of mutations causing hereditary fructose intolerance.

    Science.gov (United States)

    Kullberg-Lindh, C; Hannoun, C; Lindh, M

    2002-11-01

    Aldolase B is critical for sugar metabolism, and a catalytic deficiency due to mutations in its gene may result in hereditary fructose intolerance (HFI) syndrome, with hypoglycaemia and severe abdominal symptoms. This report describes two cases of HFI, which were identified by intravenous fructose tolerance test and a new RFLP (restriction fragment length polymorphism) test that detects the two most common mutations, A149P and A174D. The method includes PCR of a 224-base-pair segment of exon 5, a subsequent 3 h incubation with Cac8I and agarose electrophoresis, which reveals either or both of the mutations in one single reaction. The method might be useful for screening of these mutations, which may account for more than 70% of the mutations causing HFI.

  10. A nonsense mutation in FMR1 causing fragile X syndrome

    DEFF Research Database (Denmark)

    Grønskov, Karen; Brøndum-Nielsen, Karen; Dedic, Alma

    2011-01-01

    Fragile X syndrome is a common cause of inherited intellectual disability. It is caused by lack of the FMR1 gene product FMRP. The most frequent cause is the expansion of a CGG repeat located in the 5'UTR of FMR1. Alleles with 200 or more repeats become hypermethylated and transcriptionally silent...... mutation p.Ser27X, in a patient with classical clinical symptoms of fragile X syndrome. The mother who carried the mutation in heterozygous form presented with mild intellectual impairment. We conclude that further studies including western blot and DNA sequence analysis of the FMR1 gene should....... Only few patients with intragenic point mutations in FMR1 have been reported and, currently, routine analysis of patients referred for fragile X syndrome includes solely analysis for repeat expansion and methylation status. We identified a substitution in exon 2 of FMR1, c.80C>A, causing a nonsense...

  11. Heterozygous Reelin Mutations Cause Autosomal-Dominant Lateral Temporal Epilepsy

    Science.gov (United States)

    Dazzo, Emanuela; Fanciulli, Manuela; Serioli, Elena; Minervini, Giovanni; Pulitano, Patrizia; Binelli, Simona; Di Bonaventura, Carlo; Luisi, Concetta; Pasini, Elena; Striano, Salvatore; Striano, Pasquale; Coppola, Giangennaro; Chiavegato, Angela; Radovic, Slobodanka; Spadotto, Alessandro; Uzzau, Sergio; La Neve, Angela; Giallonardo, Anna Teresa; Mecarelli, Oriano; Tosatto, Silvio C.E.; Ottman, Ruth; Michelucci, Roberto; Nobile, Carlo

    2015-01-01

    Autosomal-dominant lateral temporal epilepsy (ADLTE) is a genetic epilepsy syndrome clinically characterized by focal seizures with prominent auditory symptoms. ADLTE is genetically heterogeneous, and mutations in LGI1 account for fewer than 50% of affected families. Here, we report the identification of causal mutations in reelin (RELN) in seven ADLTE-affected families without LGI1 mutations. We initially investigated 13 ADLTE-affected families by performing SNP-array linkage analysis and whole-exome sequencing and identified three heterozygous missense mutations co-segregating with the syndrome. Subsequent analysis of 15 small ADLTE-affected families revealed four additional missense mutations. 3D modeling predicted that all mutations have structural effects on protein-domain folding. Overall, RELN mutations occurred in 7/40 (17.5%) ADLTE-affected families. RELN encodes a secreted protein, Reelin, which has important functions in both the developing and adult brain and is also found in the blood serum. We show that ADLTE-related mutations significantly decrease serum levels of Reelin, suggesting an inhibitory effect of mutations on protein secretion. We also show that Reelin and LGI1 co-localize in a subset of rat brain neurons, supporting an involvement of both proteins in a common molecular pathway underlying ADLTE. Homozygous RELN mutations are known to cause lissencephaly with cerebellar hypoplasia. Our findings extend the spectrum of neurological disorders associated with RELN mutations and establish a link between RELN and LGI1, which play key regulatory roles in both the developing and adult brain. PMID:26046367

  12. [Mutations in the gene encoding filaggrin cause ichthyosis vulgaris].

    Science.gov (United States)

    Prasad, Sumangali Chandra; Rasmussen, Kirsten; Bygum, Anette

    2011-02-14

    Ichthyosis vulgaris is a common genetic skin disorder with an estimated prevalence of 1:250 caused by mutations in the gene encoding filaggrin. This disorder manifests itself within the first year of life and is clinically characterized by dry, scaly skin, keratosis pilaris, palmar hyperlinearity and atopic manifestations. Patients with a severe phenotype are homozygous or compound heterozygous for the mutations, whereas heterozygous patients show mild disease, suggesting semidominant inheritance with incomplete penetrance. We present a patient with classic severe ichthyosis vulgaris, atopic eczema and two loss-of-function mutations.

  13. Insulin gene mutations as a cause of permanent neonatal diabetes.

    Science.gov (United States)

    Støy, Julie; Edghill, Emma L; Flanagan, Sarah E; Ye, Honggang; Paz, Veronica P; Pluzhnikov, Anna; Below, Jennifer E; Hayes, M Geoffrey; Cox, Nancy J; Lipkind, Gregory M; Lipton, Rebecca B; Greeley, Siri Atma W; Patch, Ann-Marie; Ellard, Sian; Steiner, Donald F; Hattersley, Andrew T; Philipson, Louis H; Bell, Graeme I

    2007-09-18

    We report 10 heterozygous mutations in the human insulin gene in 16 probands with neonatal diabetes. A combination of linkage and a candidate gene approach in a family with four diabetic members led to the identification of the initial INS gene mutation. The mutations are inherited in an autosomal dominant manner in this and two other small families whereas the mutations in the other 13 patients are de novo. Diabetes presented in probands at a median age of 9 weeks, usually with diabetic ketoacidosis or marked hyperglycemia, was not associated with beta cell autoantibodies, and was treated from diagnosis with insulin. The mutations are in critical regions of the preproinsulin molecule, and we predict that they prevent normal folding and progression of proinsulin in the insulin secretory pathway. The abnormally folded proinsulin molecule may induce the unfolded protein response and undergo degradation in the endoplasmic reticulum, leading to severe endoplasmic reticulum stress and potentially beta cell death by apoptosis. This process has been described in both the Akita and Munich mouse models that have dominant-acting missense mutations in the Ins2 gene, leading to loss of beta cell function and mass. One of the human mutations we report here is identical to that in the Akita mouse. The identification of insulin mutations as a cause of neonatal diabetes will facilitate the diagnosis and possibly, in time, treatment of this disorder.

  14. Biallelic TBCD Mutations Cause Early-Onset Neurodegenerative Encephalopathy.

    Science.gov (United States)

    Miyake, Noriko; Fukai, Ryoko; Ohba, Chihiro; Chihara, Takahiro; Miura, Masayuki; Shimizu, Hiroshi; Kakita, Akiyoshi; Imagawa, Eri; Shiina, Masaaki; Ogata, Kazuhiro; Okuno-Yuguchi, Jiu; Fueki, Noboru; Ogiso, Yoshifumi; Suzumura, Hiroshi; Watabe, Yoshiyuki; Imataka, George; Leong, Huey Yin; Fattal-Valevski, Aviva; Kramer, Uri; Miyatake, Satoko; Kato, Mitsuhiro; Okamoto, Nobuhiko; Sato, Yoshinori; Mitsuhashi, Satomi; Nishino, Ichizo; Kaneko, Naofumi; Nishiyama, Akira; Tamura, Tomohiko; Mizuguchi, Takeshi; Nakashima, Mitsuko; Tanaka, Fumiaki; Saitsu, Hirotomo; Matsumoto, Naomichi

    2016-10-06

    We describe four families with affected siblings showing unique clinical features: early-onset (before 1 year of age) progressive diffuse brain atrophy with regression, postnatal microcephaly, postnatal growth retardation, muscle weakness/atrophy, and respiratory failure. By whole-exome sequencing, we identified biallelic TBCD mutations in eight affected individuals from the four families. TBCD encodes TBCD (tubulin folding co-factor D), which is one of five tubulin-specific chaperones playing a pivotal role in microtubule assembly in all cells. A total of seven mutations were found: five missense mutations, one nonsense, and one splice site mutation resulting in a frameshift. In vitro cell experiments revealed the impaired binding between most mutant TBCD proteins and ARL2, TBCE, and β-tubulin. The in vivo experiments using olfactory projection neurons in Drosophila melanogaster indicated that the TBCD mutations caused loss of function. The wide range of clinical severity seen in this neurodegenerative encephalopathy may result from the residual function of mutant TBCD proteins. Furthermore, the autopsied brain from one deceased individual showed characteristic neurodegenerative findings: cactus and somatic sprout formations in the residual Purkinje cells in the cerebellum, which are also seen in some diseases associated with mitochondrial impairment. Defects of microtubule formation caused by TBCD mutations may underlie the pathomechanism of this neurodegenerative encephalopathy. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  15. A DSPP mutation causing dentinogenesis imperfecta and characterization of the mutational effect.

    Science.gov (United States)

    Lee, Sook-Kyung; Lee, Kyung-Eun; Song, Su Jeong; Hyun, Hong-Keun; Lee, Sang-Hoon; Kim, Jung-Wook

    2013-01-01

    Mutations in the DSPP gene have been identified in nonsyndromic hereditary dentin defects, but the genotype-phenotype correlations are not fully understood. Recently, it has been demonstrated that the mutations of DSPP affecting the IPV leader sequence result in mutant DSPP retention in rough endoplasmic reticulum (ER). In this study, we identified a Korean family with dentinogenesis imperfecta type III. To identify the disease causing mutation in this family, we performed mutational analysis based on candidate gene sequencing. Exons and exon-intron boundaries of DSPP gene were sequenced, and the effects of the identified mutation on the pre-mRNA splicing and protein secretion were investigated. Candidate gene sequencing revealed a mutation (c.50C > T, p.P17L) in exon 2 of the DSPP gene. The splicing assay showed that the mutation did not influence pre-mRNA splicing. However, the mutation interfered with protein secretion and resulted in the mutant protein remaining largely in the ER. These results suggest that the mutation affects ER-to-Golgi apparatus export and results in the reduction of secreted DSPP and ER overload. This may induce cell stress and damage processing and/or transport of dentin matrix proteins or other critical proteins.

  16. A DSPP Mutation Causing Dentinogenesis Imperfecta and Characterization of the Mutational Effect

    Directory of Open Access Journals (Sweden)

    Sook-Kyung Lee

    2013-01-01

    Full Text Available Mutations in the DSPP gene have been identified in nonsyndromic hereditary dentin defects, but the genotype-phenotype correlations are not fully understood. Recently, it has been demonstrated that the mutations of DSPP affecting the IPV leader sequence result in mutant DSPP retention in rough endoplasmic reticulum (ER. In this study, we identified a Korean family with dentinogenesis imperfecta type III. To identify the disease causing mutation in this family, we performed mutational analysis based on candidate gene sequencing. Exons and exon-intron boundaries of DSPP gene were sequenced, and the effects of the identified mutation on the pre-mRNA splicing and protein secretion were investigated. Candidate gene sequencing revealed a mutation (c.50C > T, p.P17L in exon 2 of the DSPP gene. The splicing assay showed that the mutation did not influence pre-mRNA splicing. However, the mutation interfered with protein secretion and resulted in the mutant protein remaining largely in the ER. These results suggest that the mutation affects ER-to-Golgi apparatus export and results in the reduction of secreted DSPP and ER overload. This may induce cell stress and damage processing and/or transport of dentin matrix proteins or other critical proteins.

  17. Mutations in LPIN1 cause recurrent acute myoglobinuria in childhood.

    Science.gov (United States)

    Zeharia, Avraham; Shaag, Avraham; Houtkooper, Riekelt H; Hindi, Tareq; de Lonlay, Pascale; Erez, Gilli; Hubert, Laurence; Saada, Ann; de Keyzer, Yves; Eshel, Gideon; Vaz, Frédéric M; Pines, Ophry; Elpeleg, Orly

    2008-10-01

    Recurrent episodes of life-threatening myoglobinuria in childhood are caused by inborn errors of glycogenolysis, mitochondrial fatty acid beta-oxidation, and oxidative phosphorylation. Nonetheless, approximately half of the patients do not suffer from a defect in any of these pathways. Using homozygosity mapping, we identified six deleterious mutations in the LPIN1 gene in patients who presented at 2-7 years of age with recurrent, massive rhabdomyolysis. The LPIN1 gene encodes the muscle-specific phosphatidic acid phosphatase, a key enzyme in triglyceride and membrane phospholipid biosynthesis. Of six individuals who developed statin-induced myopathy, one was a carrier for Glu769Gly, a pathogenic mutation in the LPIN1 gene. Analysis of phospholipid content disclosed accumulation of phosphatidic acid and lysophospholipids in muscle tissue of the more severe genotype. Mutations in the LPIN1 gene cause recurrent rhabdomyolysis in childhood, and a carrier state may predispose for statin-induced myopathy.

  18. Infantile onset spinocerebellar ataxia caused by compound heterozygosity for Twinkle mutations and modeling of Twinkle mutations causing recessive disease

    Science.gov (United States)

    Gulsuner, Suleyman; Stapleton, Gail A.; Walsh, Tom; Lee, Ming K.; Mandell, Jessica B.; Morales, Augusto; Klevit, Rachel E.; King, Mary-Claire; Rogers, R. Curtis

    2016-01-01

    Mutations in nuclear genes required for the replication and maintenance of mitochondrial DNA cause progressive multisystemic neuromuscular disorders with overlapping phenotypes. Biallelic mutations in C10orf2, encoding the Twinkle mitochondrial DNA helicase, lead to infantile-onset cerebellar ataxia (IOSCA), as well as milder and more severe phenotypes. We present a 13-year-old girl with ataxia, severe hearing loss, optic atrophy, peripheral neuropathy, and hypergonadotropic hypogonadism. Whole-exome sequencing revealed that the patient is compound heterozygous for previously unreported variants in the C10orf2 gene: a paternally inherited frameshift variant (c.333delT; p.L112Sfs*3) and a maternally inherited missense variant (c.904C>T; p.R302W). The identification of novel C10orf2 mutations extends the spectrum of mutations in the Twinkle helicase causing recessive disease, in particular the intermediate IOSCA phenotype. Structural modeling suggests that the p.R302W mutation and many other recessively inherited Twinkle mutations impact the position or interactions of the linker region, which is critical for the oligomeric ring structure and activity of the helicase. This study emphasizes the utility of whole-exome sequencing for the genetic diagnosis of a complex multisystemic disorder. PMID:27551684

  19. Mutations found in the Danish population causing Hereditary Hemorrhagic Telangiectasia

    DEFF Research Database (Denmark)

    Tørring, Pernille M; Brusgaard, Klaus

    2011-01-01

    University Hospital, Denmark HHT is an autosomal vascular disorder caused by mutations of either of three loci ENG, ACVLR1 or MADH4. HHT is characterised by recurrent nosebleeds, mucocutaneous telangiectases, and more severe visceral malformations. During the last decade the Danish HHT centre has...

  20. Familial gigantism caused by an NSD1 mutation.

    NARCIS (Netherlands)

    Haelst, M.M. van; Hoogeboom, J.J.; Baujat, G.; Bruggenwirth, H.T.; Laar, I. van de; Coleman, K.; Rahman, N.; Niermeijer, M.F.; Drop, S.L.; Scambler, P.J.

    2005-01-01

    A three-generation family with autosomal dominant segregation of a novel NSD1 mutation (6605G --> A, resulting in Cys2202Tyr) is reported. Haploinsufficiency of NSD1 has been identified as the major cause of Sotos syndrome. The overgrowth condition (MIM 117550) is characterized by facial anomalie

  1. A sodium-channel mutation causes isolated cardiac conduction disease

    NARCIS (Netherlands)

    Tan, HL; Bink-Boelkens, MTE; Bezzina, CR; Viswanathan, PC; Beaufort-Krol, GCM; van Tintelen, PJ; van den Berg, MP; Wilde, AAM; Balser, [No Value

    2001-01-01

    Cardiac conduction disorders slow the heart rhythm and cause disability in millions of people worldwide. Inherited mutations in SCN5A, the gene encoding the human cardiac sodium (Na+) channel, have been associated with rapid heart rhythms that occur suddenly and are life-threatening(1-3); however, a

  2. Hereditary spastic paraplegia caused by the PLP1 'rumpshaker mutation'

    DEFF Research Database (Denmark)

    Svenstrup, Kirsten; Giraud, Geneviève; Boespflug-Tanguy, Odile

    2010-01-01

    BACKGROUND: Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative disorders characterised by progressive spasticity and weakness in the lower limbs. Mutations in PLP1 on the X chromosome cause spastic paraplegia type 2 (SPG2) or the allelic...

  3. Mutations in the pericentrin (PCNT) gene cause primordial dwarfism.

    NARCIS (Netherlands)

    Rauch, A.; Thiel, C.T.; Schindler, D.; Wick, U.; Crow, Y.J.; Ekici, A.B.; Essen, A.J. van; Goecke, T.O.; Al-Gazali, L.; Chrzanowska, K.H.; Zweier, C.; Brunner, H.G.; Becker, K.; Curry, C.J.; Dallapiccola, B.; Devriendt, K.; Dorfler, A.; Kinning, E.; Megarbane, A.; Meinecke, P.; Semple, R.K.; Spranger, S.; Toutain, A.; Trembath, R.C.; Voss, E.; Wilson, L.; Hennekam, R.C.M.; Zegher, F. de; Dorr, H.G.; Reis, A.

    2008-01-01

    Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss-of-function mutations in the centrosomal pericentrin (PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial dwarfism

  4. Mutations in the pericentrin (PCNT) gene cause primordial dwarfism

    NARCIS (Netherlands)

    Rauch, Anita; Thiel, Christian T.; Schindler, Detlev; Wick, Ursula; Crow, Yanick J.; Ekici, Arif B.; van Essen, Anthonie J.; Goecke, Timm O.; Al-Gazali, Lihadh; Chrzanowska, Krystyna H.; Zweier, Christiane; Brunner, Han G.; Becker, Kristin; Curry, Cynthia J.; Dallapiccola, Bruno; Devriendt, Koenraad; Doerfler, Arnd; Kinning, Esther; Megarbane, Andre; Meinecke, Peter; Semple, Robert K.; Spranger, Stephanie; Toutain, Annick; Trembath, Richard C.; Voss, Egbert; Wilson, Louise; Hennekam, Raoul; de Zegher, Francis; Doerr, Helmuth-Guenther; Reis, Andre

    2008-01-01

    Fundamental processes influencing human growth can be revealed by studying extreme short stature. Using genetic linkage analysis, we find that biallelic loss- of- function mutations in the centrosomal pericentrin ( PCNT) gene on chromosome 21q22.3 cause microcephalic osteodysplastic primordial

  5. A new amyloidosis caused by fibrillar aggregates of mutated corneodesmosin

    DEFF Research Database (Denmark)

    Caubet, Cécile; Bousset, Luc; Clemmensen, Ole

    2010-01-01

    Heterozygous nonsense mutations in the CDSN gene encoding corneodesmosin (CDSN), an adhesive protein expressed in cornified epithelia and hair follicles, cause hypotrichosis simplex of the scalp (HSS), a nonsyndromic form of alopecia. Truncated mutants of CDSN ((mut)CDSN), which bear the N...

  6. Homozygous SLC2A9 mutations cause severe renal hypouricemia.

    Science.gov (United States)

    Dinour, Dganit; Gray, Nicola K; Campbell, Susan; Shu, Xinhua; Sawyer, Lindsay; Richardson, William; Rechavi, Gideon; Amariglio, Ninette; Ganon, Liat; Sela, Ben-Ami; Bahat, Hilla; Goldman, Michael; Weissgarten, Joshua; Millar, Michael R; Wright, Alan F; Holtzman, Eliezer J

    2010-01-01

    Hereditary hypouricemia may result from mutations in the renal tubular uric acid transporter URAT1. Whether mutation of other uric acid transporters produces a similar phenotype is unknown. We studied two families who had severe hereditary hypouricemia and did not have a URAT1 defect. We performed a genome-wide homozygosity screen and linkage analysis and identified the candidate gene SLC2A9, which encodes the glucose transporter 9 (GLUT9). Both families had homozygous SLC2A9 mutations: A missense mutation (L75R) in six affected members of one family and a 36-kb deletion, resulting in a truncated protein, in the other. In vitro, the L75R mutation dramatically impaired transport of uric acid. The mean concentration of serum uric acid of seven homozygous individuals was 0.17 +/- 0.2 mg/dl, and all had a fractional excretion of uric acid >150%. Three individuals had nephrolithiasis, and three had a history of exercise-induced acute renal failure. In conclusion, homozygous loss-of-function mutations of GLUT9 cause a total defect of uric acid absorption, leading to severe renal hypouricemia complicated by nephrolithiasis and exercise-induced acute renal failure. In addition to clarifying renal handling of uric acid, our findings may provide a better understanding of the pathophysiology of acute renal failure, nephrolithiasis, hyperuricemia, and gout.

  7. LMX1B Mutations Cause Hereditary FSGS without Extrarenal Involvement

    Science.gov (United States)

    Boyer, Olivia; Woerner, Stéphanie; Yang, Fan; Oakeley, Edward J.; Linghu, Bolan; Gribouval, Olivier; Tête, Marie-Josèphe; Duca, José S.; Klickstein, Lloyd; Damask, Amy J.; Szustakowski, Joseph D.; Heibel, Françoise; Matignon, Marie; Baudouin, Véronique; Chantrel, François; Champigneulle, Jacqueline; Martin, Laurent; Nitschké, Patrick; Gubler, Marie-Claire; Johnson, Keith J.; Chibout, Salah-Dine

    2013-01-01

    LMX1B encodes a homeodomain-containing transcription factor that is essential during development. Mutations in LMX1B cause nail-patella syndrome, characterized by dysplasia of the patellae, nails, and elbows and FSGS with specific ultrastructural lesions of the glomerular basement membrane (GBM). By linkage analysis and exome sequencing, we unexpectedly identified an LMX1B mutation segregating with disease in a pedigree of five patients with autosomal dominant FSGS but without either extrarenal features or ultrastructural abnormalities of the GBM suggestive of nail-patella–like renal disease. Subsequently, we screened 73 additional unrelated families with FSGS and found mutations involving the same amino acid (R246) in 2 families. An LMX1B in silico homology model suggested that the mutated residue plays an important role in strengthening the interaction between the LMX1B homeodomain and DNA; both identified mutations would be expected to diminish such interactions. In summary, these results suggest that isolated FSGS could result from mutations in genes that are also involved in syndromic forms of FSGS. This highlights the need to include these genes in all diagnostic approaches to FSGS that involve next-generation sequencing. PMID:23687361

  8. Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death

    DEFF Research Database (Denmark)

    Nyegaard, Mette; Overgaard, Michael Toft; Søndergaard, Mads

    2012-01-01

    Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause...... calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac...

  9. Mutations in KCTD1 cause scalp-ear-nipple syndrome.

    Science.gov (United States)

    Marneros, Alexander G; Beck, Anita E; Turner, Emily H; McMillin, Margaret J; Edwards, Matthew J; Field, Michael; de Macena Sobreira, Nara Lygia; Perez, Ana Beatriz A; Fortes, Jose A R; Lampe, Anne K; Giovannucci Uzielli, Maria Luisa; Gordon, Christopher T; Plessis, Ghislaine; Le Merrer, Martine; Amiel, Jeanne; Reichenberger, Ernst; Shively, Kathryn M; Cerrato, Felecia; Labow, Brian I; Tabor, Holly K; Smith, Joshua D; Shendure, Jay; Nickerson, Deborah A; Bamshad, Michael J

    2013-04-04

    Scalp-ear-nipple (SEN) syndrome is a rare, autosomal-dominant disorder characterized by cutis aplasia of the scalp; minor anomalies of the external ears, digits, and nails; and malformations of the breast. We used linkage analysis and exome sequencing of a multiplex family affected by SEN syndrome to identify potassium-channel tetramerization-domain-containing 1 (KCTD1) mutations that cause SEN syndrome. Evaluation of a total of ten families affected by SEN syndrome revealed KCTD1 missense mutations in each family tested. All of the mutations occurred in a KCTD1 region encoding a highly conserved bric-a-brac, tram track, and broad complex (BTB) domain that is required for transcriptional repressor activity. KCTD1 inhibits the transactivation of the transcription factor AP-2α (TFAP2A) via its BTB domain, and mutations in TFAP2A cause cutis aplasia in individuals with branchiooculofacial syndrome (BOFS), suggesting a potential overlap in the pathogenesis of SEN syndrome and BOFS. The identification of KCTD1 mutations in SEN syndrome reveals a role for this BTB-domain-containing transcriptional repressor during ectodermal development.

  10. Dominant de novo DSP mutations cause erythrokeratodermia-cardiomyopathy syndrome.

    Science.gov (United States)

    Boyden, Lynn M; Kam, Chen Y; Hernández-Martín, Angela; Zhou, Jing; Craiglow, Brittany G; Sidbury, Robert; Mathes, Erin F; Maguiness, Sheilagh M; Crumrine, Debra A; Williams, Mary L; Hu, Ronghua; Lifton, Richard P; Elias, Peter M; Green, Kathleen J; Choate, Keith A

    2016-01-15

    Disorders of keratinization (DOK) show marked genotypic and phenotypic heterogeneity. In most cases, disease is primarily cutaneous, and further clinical evaluation is therefore rarely pursued. We have identified subjects with a novel DOK featuring erythrokeratodermia and initially-asymptomatic, progressive, potentially fatal cardiomyopathy, a finding not previously associated with erythrokeratodermia. We show that de novo missense mutations clustered tightly within a single spectrin repeat of DSP cause this novel cardio-cutaneous disorder, which we term erythrokeratodermia-cardiomyopathy (EKC) syndrome. We demonstrate that DSP mutations in our EKC syndrome subjects affect localization of desmosomal proteins and connexin 43 in the skin, and result in desmosome aggregation, widening of intercellular spaces, and lipid secretory defects. DSP encodes desmoplakin, a primary component of desmosomes, intercellular adhesion junctions most abundant in the epidermis and heart. Though mutations in DSP are known to cause other disorders, our cohort features the unique clinical finding of severe whole-body erythrokeratodermia, with distinct effects on localization of desmosomal proteins and connexin 43. These findings add a severe, previously undescribed syndrome featuring erythrokeratodermia and cardiomyopathy to the spectrum of disease caused by mutation in DSP, and identify a specific region of the protein critical to the pathobiology of EKC syndrome and to DSP function in the heart and skin. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Novel mutations in PXDN cause microphthalmia and anterior segment dysgenesis.

    Science.gov (United States)

    Choi, Alex; Lao, Richard; Ling-Fung Tang, Paul; Wan, Eunice; Mayer, Wasima; Bardakjian, Tanya; Shaw, Gary M; Kwok, Pui-Yan; Schneider, Adele; Slavotinek, Anne

    2015-03-01

    We used exome sequencing to study a non-consanguineous family with two children who had anterior segment dysgenesis, sclerocornea, microphthalmia, hypotonia and developmental delays. Sanger sequencing verified two Peroxidasin (PXDN) mutations in both sibs--a maternally inherited, nonsense mutation, c.1021C>T predicting p.(Arg341*), and a paternally inherited, 23-basepair deletion causing a frameshift and premature protein truncation, c.2375_2397del23, predicting p.(Leu792Hisfs*67). We re-examined exome data from 20 other patients with structural eye defects and identified two additional PXDN mutations in a sporadic male with bilateral microphthalmia, cataracts and anterior segment dysgenesis--a maternally inherited, frameshift mutation, c.1192delT, predicting p.(Tyr398Thrfs*40) and a paternally inherited, missense substitution that was predicted to be deleterious, c.947 A>C, predicting p.(Gln316Pro). Mutations in PXDN were previously reported in three families with congenital cataracts, microcornea, sclerocornea and developmental glaucoma. The gene is expressed in corneal epithelium and is secreted into the extracellular matrix. Defective peroxidasin has been shown to impair sulfilimine bond formation in collagen IV, a constituent of the basement membrane, implying that the eye defects result because of loss of basement membrane integrity in the developing eye. Our finding of a broader phenotype than previously appreciated for PXDN mutations is typical for exome-sequencing studies, which have proven to be highly effective for mutation detection in patients with atypical presentations. We conclude that PXDN sequencing should be considered in microphthalmia with anterior segment dysgenesis.

  12. Dominant KCNA2 mutation causes episodic ataxia and pharmacoresponsive epilepsy.

    Science.gov (United States)

    Corbett, Mark A; Bellows, Susannah T; Li, Melody; Carroll, Renée; Micallef, Silvana; Carvill, Gemma L; Myers, Candace T; Howell, Katherine B; Maljevic, Snezana; Lerche, Holger; Gazina, Elena V; Mefford, Heather C; Bahlo, Melanie; Berkovic, Samuel F; Petrou, Steven; Scheffer, Ingrid E; Gecz, Jozef

    2016-11-08

    To identify the genetic basis of a family segregating episodic ataxia, infantile seizures, and heterogeneous epilepsies and to study the phenotypic spectrum of KCNA2 mutations. A family with 7 affected individuals over 3 generations underwent detailed phenotyping. Whole genome sequencing was performed on a mildly affected grandmother and her grandson with epileptic encephalopathy (EE). Segregating variants were filtered and prioritized based on functional annotations. The effects of the mutation on channel function were analyzed in vitro by voltage clamp assay and in silico by molecular modeling. KCNA2 was sequenced in 35 probands with heterogeneous phenotypes. The 7 family members had episodic ataxia (5), self-limited infantile seizures (5), evolving to genetic generalized epilepsy (4), focal seizures (2), and EE (1). They had a segregating novel mutation in the shaker type voltage-gated potassium channel KCNA2 (CCDS_827.1: c.765_773del; p.255_257del). A rare missense SCN2A (rs200884216) variant was also found in 2 affected siblings and their unaffected mother. The p.255_257del mutation caused dominant negative loss of channel function. Molecular modeling predicted repositioning of critical arginine residues in the voltage-sensing domain. KCNA2 sequencing revealed 1 de novo mutation (CCDS_827.1: c.890G>A; p.Arg297Gln) in a girl with EE, ataxia, and tremor. A KCNA2 mutation caused dominantly inherited episodic ataxia, mild infantile-onset seizures, and later generalized and focal epilepsies in the setting of normal intellect. This observation expands the KCNA2 phenotypic spectrum from EE often associated with chronic ataxia, reflecting the marked variation in severity observed in many ion channel disorders. © 2016 American Academy of Neurology.

  13. A novel KCNA1 mutation causing episodic ataxia type I.

    Science.gov (United States)

    Lassche, Saskia; Lainez, Sergio; Bloem, Bastiaan R; van de Warrenburg, Bart P C; Hofmeijer, Jeannette; Lemmink, Henny H; Hoenderop, Joost G J; Bindels, René J M; Drost, Gea

    2014-08-01

    We describe the clinical phenotype of a novel de novo KNCA1 mutation, and functional characterization of the effects of the mutation on Kv1.1 channel function. HEK293 cells were transfected transiently with either wild-type or mutant channels. Representative currents were evoked after application of a series of square voltage steps from -80 mV to +50 mV in 200-ms intervals from Vh = -80 mV. Extracellular K(+) was added to evoke tail currents. Equal amounts of wild-type and Kv1.1(I262M) mutant DNA were transfected transiently in HEK293 cells to evaluate the influence of the mutation. We found that Kv1.1(I262M) leads to a defective voltage-gated potassium channel. Coexpression studies revealed a dominant-negative effect. We describe the phenotype of a novel KCNA1 mutation causing episodic ataxia. Patch-clamp studies confirm the pathogenicity of the mutation in vitro and suggest that it is dominant with respect to wild-type. Copyright © 2014 Wiley Periodicals, Inc.

  14. An MRPS12 mutation modifies aminoglycoside sensitivity caused by 12S rRNA mutations

    Directory of Open Access Journals (Sweden)

    Sonia eEmperador

    2015-01-01

    Full Text Available Several homoplasmic pathologic mutations in mitochondrial DNA, such as those causing Leber hereditary optic neuropathy or non-syndromic hearing loss, show incomplete penetrance. Therefore, other elements must modify their pathogenicity. Discovery of these modifying factors is not an easy task because in multifactorial diseases conventional genetic approaches may not always be informative.Here, we have taken an evolutionary approach to unmask putative modifying factors for a particular homoplasmic pathologic mutation causing aminoglycoside-induced and non-syndromic hearing loss, the m.1494C>T transition in the mitochondrial DNA. The mutation is located in the decoding site of the mitochondrial ribosomal RNA. We first looked at mammalian species that had fixed the human pathologic mutation. These mutations are called compensated pathogenic deviations because an organism carrying one must also have another that suppresses the deleterious effect of the first. We found that species from the primate family Cercopithecidae (old world monkeys harbor the m.1494T allele even if their auditory function is normal.In humans the m.1494T allele increases the susceptibility to aminoglycosides. However, in primary fibroblasts from a Cercopithecidae species, aminoglycosides do not impair cell growth, respiratory complex IV activity and quantity or the mitochondrial protein synthesis. Interestingly, these species also carry a fixed mutation in the mitochondrial ribosomal protein S12. We show that the expression of this variant in a human m.1494T cell line reduces its susceptibility to aminoglycosides. Because several mutations in this human protein have been described, they may possibly explain the absence of pathologic phenotype in some pedigree members with the most frequent pathologic mutations in mitochondrial ribosomal RNA.

  15. Mutations in KDSR Cause Recessive Progressive Symmetric Erythrokeratoderma.

    Science.gov (United States)

    Boyden, Lynn M; Vincent, Nicholas G; Zhou, Jing; Hu, Ronghua; Craiglow, Brittany G; Bayliss, Susan J; Rosman, Ilana S; Lucky, Anne W; Diaz, Luis A; Goldsmith, Lowell A; Paller, Amy S; Lifton, Richard P; Baserga, Susan J; Choate, Keith A

    2017-06-01

    The discovery of new genetic determinants of inherited skin disorders has been instrumental to the understanding of epidermal function, differentiation, and renewal. Here, we show that mutations in KDSR (3-ketodihydrosphingosine reductase), encoding an enzyme in the ceramide synthesis pathway, lead to a previously undescribed recessive Mendelian disorder in the progressive symmetric erythrokeratoderma spectrum. This disorder is characterized by severe lesions of thick scaly skin on the face and genitals and thickened, red, and scaly skin on the hands and feet. Although exome sequencing revealed several of the KDSR mutations, we employed genome sequencing to discover a pathogenic 346 kb inversion in multiple probands, and cDNA sequencing and a splicing assay established that two mutations, including a recurrent silent third base change, cause exon skipping. Immunohistochemistry and yeast complementation studies demonstrated that the mutations cause defects in KDSR function. Systemic isotretinoin therapy has achieved nearly complete resolution in the two probands in whom it has been applied, consistent with the effects of retinoic acid on alternative pathways for ceramide generation. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  16. Mutations in LPIN1 Cause Recurrent Acute Myoglobinuria in Childhood

    OpenAIRE

    Zeharia, Avraham; Shaag, Avraham; Houtkooper, Riekelt H.; Hindi, Tareq; de Lonlay, Pascale; Erez, Gilli; Hubert, Laurence; Saada, Ann; de Keyzer, Yves; Eshel, Gideon; Vaz, Frédéric M.; Pines, Ophry; Elpeleg, Orly

    2008-01-01

    Recurrent episodes of life-threatening myoglobinuria in childhood are caused by inborn errors of glycogenolysis, mitochondrial fatty acid beta-oxidation, and oxidative phosphorylation. Nonetheless, approximately half of the patients do not suffer from a defect in any of these pathways. Using homozygosity mapping, we identified six deleterious mutations in the LPIN1 gene in patients who presented at 2–7 years of age with recurrent, massive rhabdomyolysis. The LPIN1 gene encodes the muscle-spec...

  17. Mutations in LPIN1 Cause Recurrent Acute Myoglobinuria in Childhood

    OpenAIRE

    Zeharia, Avraham; Shaag, Avraham; Houtkooper, Riekelt H.; Hindi, Tareq; De Lonlay, Pascale; Erez, Gilli; Hubert, Laurence; Saada, Ann; de Keyzer, Yves; Eshel, Gideon; Vaz, Frédéric M.; Pines, Ophry; Elpeleg, Orly

    2008-01-01

    Recurrent episodes of life-threatening myoglobinuria in childhood are caused by inborn errors of glycogenolysis, mitochondrial fatty acid beta-oxidation, and oxidative phosphorylation. Nonetheless, approximately half of the patients do not suffer from a defect in any of these pathways. Using homozygosity mapping, we identified six deleterious mutations in the LPIN1 gene in patients who presented at 2–7 years of age with recurrent, massive rhabdomyolysis. The LPIN1 gene encodes the muscle-spec...

  18. Mutations in the NHEJ component XRCC4 cause primordial dwarfism.

    Science.gov (United States)

    Murray, Jennie E; van der Burg, Mirjam; IJspeert, Hanna; Carroll, Paula; Wu, Qian; Ochi, Takashi; Leitch, Andrea; Miller, Edward S; Kysela, Boris; Jawad, Alireza; Bottani, Armand; Brancati, Francesco; Cappa, Marco; Cormier-Daire, Valerie; Deshpande, Charu; Faqeih, Eissa A; Graham, Gail E; Ranza, Emmanuelle; Blundell, Tom L; Jackson, Andrew P; Stewart, Grant S; Bicknell, Louise S

    2015-03-05

    Non-homologous end joining (NHEJ) is a key cellular process ensuring genome integrity. Mutations in several components of the NHEJ pathway have been identified, often associated with severe combined immunodeficiency (SCID), consistent with the requirement for NHEJ during V(D)J recombination to ensure diversity of the adaptive immune system. In contrast, we have recently found that biallelic mutations in LIG4 are a common cause of microcephalic primordial dwarfism (MPD), a phenotype characterized by prenatal-onset extreme global growth failure. Here we provide definitive molecular genetic evidence supported by biochemical, cellular, and immunological data for mutations in XRCC4, encoding the obligate binding partner of LIG4, causing MPD. We report the identification of biallelic mutations in XRCC4 in five families. Biochemical and cellular studies demonstrate that these alterations substantially decrease XRCC4 protein levels leading to reduced cellular ligase IV activity. Consequently, NHEJ-dependent repair of ionizing-radiation-induced DNA double-strand breaks is compromised in XRCC4 cells. Similarly, immunoglobulin junctional diversification is impaired in cells. However, immunoglobulin levels are normal, and individuals lack overt signs of immunodeficiency. Additionally, in contrast to individuals with LIG4 mutations, pancytopenia leading to bone marrow failure has not been observed. Hence, alterations that alter different NHEJ proteins give rise to a phenotypic spectrum, from SCID to extreme growth failure, with deficiencies in certain key components of this repair pathway predominantly exhibiting growth deficits, reflecting differential developmental requirements for NHEJ proteins to support growth and immune maturation. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  19. Targeting Androgen Receptor-Driven Resistance to CYP17A1 Inhibitors

    Science.gov (United States)

    2016-11-01

    Ph.D. CONTRACTING ORGANIZATION: Health Research Inc. Buffalo, NY 14263 REPORT DATE: November 2016 TYPE OF REPORT: Final PREPARED FOR: U.S. Army...ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Health Research Inc. Buffalo, NY 14263 9. SPONSORING / MONITORING AGENCY...Organizations………………. 7 Special Reporting Requirements …………………………………… 7 Appendices…………………………………………………………… 7 PCRP- Hypothesis Development Award

  20. Targeting Androgen Receptor-Driven Resistance to CYP17A1 Inhibitors

    Science.gov (United States)

    2015-09-01

    DNA fragments from human Y-chromosome BAC clones containing and flanking the AR locus, ligate to Illumina library adapters plus adapters for 5’-AgeI...high” and “low” GFP-expressing 22Rv1 cells transiently transfected with the 3 AR BAC STARR- seq libraries (as shown in Fig. 2). Plasmid DNAs isolated...using a 96- well plates. Individual DNAs from these sub- libraries were transfected into LNCaP vs. C4-2 cells or into 22Rv1 cells, and the 22Rv1 cell

  1. Mandibuloacral Dysplasia Caused by LMNA Mutations and Uniparental Disomy

    Directory of Open Access Journals (Sweden)

    Shaochun Bai

    2014-01-01

    Full Text Available Mandibuloacral dysplasia (MAD is a rare autosomal recessive disorder characterized by postnatal growth retardation, craniofacial anomalies, skeletal malformations, and mottled cutaneous pigmentation. Hutchinson-Gilford Progeria Syndrome (HGPS is characterized by the clinical features of accelerated aging in childhood. Both MAD and HGPS can be caused by mutations in the LMNA gene. In this study, we describe a 2-year-old boy with overlapping features of MAD and HGPS. Mutation analysis of the LMNA gene revealed a homozygous missense change, p.M540T, while only the mother carries the mutation. Uniparental disomy (UPD analysis for chromosome 1 showed the presence of maternal UPD. Markers in the 1q21.3–q22 region flanking the LMNA locus were isodisomic, while markers in the short arm and distal 1q region were heterodisomic. These results suggest that nondisjunction in maternal meiosis followed by loss of the paternal chromosome 1 during trisomy rescue might result in the UPD1 and homozygosity for the p.M540T mutation observed in this patient.

  2. SPATACSIN mutations cause autosomal recessive juvenile amyotrophic lateral sclerosis.

    Science.gov (United States)

    Orlacchio, Antonio; Babalini, Carla; Borreca, Antonella; Patrono, Clarice; Massa, Roberto; Basaran, Sarenur; Munhoz, Renato P; Rogaeva, Ekaterina A; St George-Hyslop, Peter H; Bernardi, Giorgio; Kawarai, Toshitaka

    2010-02-01

    The mutation of the spatacsin gene is the single most common cause of autosomal recessive hereditary spastic paraplegia with thin corpus callosum. Common clinical, pathological and genetic features between amyotrophic lateral sclerosis and hereditary spastic paraplegia motivated us to investigate 25 families with autosomal recessive juvenile amyotrophic lateral sclerosis and long-term survival for mutations in the spatascin gene. The inclusion criterion was a diagnosis of clinically definite amyotrophic lateral sclerosis according to the revised El Escorial criteria. The exclusion criterion was a diagnosis of hereditary spastic paraplegia with thin corpus callosum in line with an established protocol. Additional pathological and genetic evaluations were also performed. Surprisingly, 12 sequence alterations in the spatacsin gene (one of which is novel, IVS30 + 1 G > A) were identified in 10 unrelated pedigrees with autosomal recessive juvenile amyotrophic lateral sclerosis and long-term survival. The countries of origin of these families were Italy, Brazil, Canada, Japan and Turkey. The variants seemed to be pathogenic since they co-segregated with the disease in all pedigrees, were absent in controls and were associated with amyotrophic lateral sclerosis neuropathology in one member of one of these families for whom central nervous system tissue was available. Our study indicates that mutations in the spatascin gene could cause a much wider spectrum of clinical features than previously recognized, including autosomal recessive juvenile amyotrophic lateral sclerosis.

  3. CSB-PGBD3 Mutations Cause Premature Ovarian Failure.

    Directory of Open Access Journals (Sweden)

    Yingying Qin

    2015-07-01

    Full Text Available Premature ovarian failure (POF is a rare, heterogeneous disorder characterized by cessation of menstruation occurring before the age of 40 years. Genetic etiology is responsible for perhaps 25% of cases, but most cases are sporadic and unexplained. In this study, through whole exome sequencing in a non-consanguineous family having four affected members with POF and Sanger sequencing in 432 sporadic cases, we identified three novel mutations in the fusion gene CSB-PGBD3. Subsequently functional studies suggest that mutated CSB-PGBD3 fusion protein was impaired in response to DNA damage, as indicated by delayed or absent recruitment to damaged sites. Our data provide the first evidence that mutations in the CSB-PGBD3 fusion protein can cause human disease, even in the presence of functional CSB, thus potentially explaining conservation of the fusion protein for 43 My since marmoset. The localization of the CSB-PGBD3 fusion protein to UVA-induced nuclear DNA repair foci further suggests that the CSB-PGBD3 fusion protein, like many other proteins that can cause POF, modulates or participates in DNA repair.

  4. Similar compositional biases are caused by very different mutational effects

    Science.gov (United States)

    Rocha, Eduardo P.C.; Touchon, Marie; Feil, Edward J.

    2006-01-01

    Compositional replication strand bias, commonly referred to as GC skew, is present in many genomes of prokaryotes, eukaryotes, and viruses. Although cytosine deamination in ssDNA (resulting in C→T changes on the leading strand) is often invoked as its major cause, the precise contributions of this and other substitution types are currently unknown. It is also unclear if the underlying mutational asymmetries are the same among taxa, are stable over time, or how closely the observed biases are to mutational equilibrium. We analyzed nearly neutral sites of seven taxa each with between three and six complete bacterial genomes, and inferred the substitution spectra of fourfold degenerate positions in nonhighly expressed genes. Using a bootstrap procedure, we extracted compositional biases associated with replication and identified the significant asymmetries. Although all taxa showed an overrepresentation of G relative to C on the leading strand (and imbalances between A and T), widely variable substitution asymmetries are noted. Surprisingly, all substitution types show significant asymmetry in at least one taxon, but none were universally biased in all taxa. Notably, in the two most biased genomes, A→G, rather than C→T, shapes the compositional bias. Given the variability in these biases, we propose that the process is multifactorial. Finally, we also find that most genomes are not at compositional equilibrium, and suggest that mutational-based heterotachy is deeply imprinted in the history of biological macromolecules. This shows that similar compositional biases associated with the same essential well-conserved process, replication, do not reflect similar mutational processes in different genomes, and that caution is required in inferring the roles of specific mutational biases on the basis of contemporary patterns of sequence composition. PMID:17068325

  5. CtIP Mutations Cause Seckel and Jawad Syndromes.

    Directory of Open Access Journals (Sweden)

    Per Qvist

    2011-10-01

    Full Text Available Seckel syndrome is a recessively inherited dwarfism disorder characterized by microcephaly and a unique head profile. Genetically, it constitutes a heterogeneous condition, with several loci mapped (SCKL1-5 but only three disease genes identified: the ATR, CENPJ, and CEP152 genes that control cellular responses to DNA damage. We previously mapped a Seckel syndrome locus to chromosome 18p11.31-q11.2 (SCKL2. Here, we report two mutations in the CtIP (RBBP8 gene within this locus that result in expression of C-terminally truncated forms of CtIP. We propose that these mutations are the molecular cause of the disease observed in the previously described SCKL2 family and in an additional unrelated family diagnosed with a similar form of congenital microcephaly termed Jawad syndrome. While an exonic frameshift mutation was found in the Jawad family, the SCKL2 family carries a splicing mutation that yields a dominant-negative form of CtIP. Further characterization of cell lines derived from the SCKL2 family revealed defective DNA damage induced formation of single-stranded DNA, a critical co-factor for ATR activation. Accordingly, SCKL2 cells present a lowered apoptopic threshold and hypersensitivity to DNA damage. Notably, over-expression of a comparable truncated CtIP variant in non-Seckel cells recapitulates SCKL2 cellular phenotypes in a dose-dependent manner. This work thus identifies CtIP as a disease gene for Seckel and Jawad syndromes and defines a new type of genetic disease mechanism in which a dominant negative mutation yields a recessively inherited disorder.

  6. CtIP Mutations Cause Seckel and Jawad Syndromes.

    Directory of Open Access Journals (Sweden)

    Per Qvist

    2011-10-01

    Full Text Available Seckel syndrome is a recessively inherited dwarfism disorder characterized by microcephaly and a unique head profile. Genetically, it constitutes a heterogeneous condition, with several loci mapped (SCKL1-5 but only three disease genes identified: the ATR, CENPJ, and CEP152 genes that control cellular responses to DNA damage. We previously mapped a Seckel syndrome locus to chromosome 18p11.31-q11.2 (SCKL2. Here, we report two mutations in the CtIP (RBBP8 gene within this locus that result in expression of C-terminally truncated forms of CtIP. We propose that these mutations are the molecular cause of the disease observed in the previously described SCKL2 family and in an additional unrelated family diagnosed with a similar form of congenital microcephaly termed Jawad syndrome. While an exonic frameshift mutation was found in the Jawad family, the SCKL2 family carries a splicing mutation that yields a dominant-negative form of CtIP. Further characterization of cell lines derived from the SCKL2 family revealed defective DNA damage induced formation of single-stranded DNA, a critical co-factor for ATR activation. Accordingly, SCKL2 cells present a lowered apoptopic threshold and hypersensitivity to DNA damage. Notably, over-expression of a comparable truncated CtIP variant in non-Seckel cells recapitulates SCKL2 cellular phenotypes in a dose-dependent manner. This work thus identifies CtIP as a disease gene for Seckel and Jawad syndromes and defines a new type of genetic disease mechanism in which a dominant negative mutation yields a recessively inherited disorder.

  7. KITLG Mutations Cause Familial Progressive Hyper- and Hypopigmentation

    DEFF Research Database (Denmark)

    Amyere, Mustapha; Vogt, Thomas; Hoo, Joe;

    2011-01-01

    Familial progressive hyper- and hypopigmentation (FPHH) is thought to be an autosomal dominant disorder with reduced penetrance. Clinical signs consist of progressive diffuse, partly blotchy hyperpigmented lesions, multiple café-au-lait spots, intermingled with scattered hypopigmented-appearing m......Familial progressive hyper- and hypopigmentation (FPHH) is thought to be an autosomal dominant disorder with reduced penetrance. Clinical signs consist of progressive diffuse, partly blotchy hyperpigmented lesions, multiple café-au-lait spots, intermingled with scattered hypopigmented...... by familial café-au-lait spots and skin fold freckling, caused by mutations in SPRED1. We performed a genome-wide linkage analysis in seven families with FPHH, and identified linkage on 12q21.12-q22, which overlaps with the DUH2 locus. We investigated whether KITLG in the locus is mutated in FPHH. We...

  8. Mutations in KPTN Cause Macrocephaly, Neurodevelopmental Delay, and Seizures

    Science.gov (United States)

    Baple, Emma L.; Maroofian, Reza; Chioza, Barry A.; Izadi, Maryam; Cross, Harold E.; Al-Turki, Saeed; Barwick, Katy; Skrzypiec, Anna; Pawlak, Robert; Wagner, Karin; Coblentz, Roselyn; Zainy, Tala; Patton, Michael A.; Mansour, Sahar; Rich, Phillip; Qualmann, Britta; Hurles, Matt E.; Kessels, Michael M.; Crosby, Andrew H.

    2014-01-01

    The proper development of neuronal circuits during neuromorphogenesis and neuronal-network formation is critically dependent on a coordinated and intricate series of molecular and cellular cues and responses. Although the cortical actin cytoskeleton is known to play a key role in neuromorphogenesis, relatively little is known about the specific molecules important for this process. Using linkage analysis and whole-exome sequencing on samples from families from the Amish community of Ohio, we have demonstrated that mutations in KPTN, encoding kaptin, cause a syndrome typified by macrocephaly, neurodevelopmental delay, and seizures. Our immunofluorescence analyses in primary neuronal cell cultures showed that endogenous and GFP-tagged kaptin associates with dynamic actin cytoskeletal structures and that this association is lost upon introduction of the identified mutations. Taken together, our studies have identified kaptin alterations responsible for macrocephaly and neurodevelopmental delay and define kaptin as a molecule crucial for normal human neuromorphogenesis. PMID:24239382

  9. Mutations in PYCR1 cause cutis laxa with progeroid features.

    Science.gov (United States)

    Reversade, Bruno; Escande-Beillard, Nathalie; Dimopoulou, Aikaterini; Fischer, Björn; Chng, Serene C; Li, Yun; Shboul, Mohammad; Tham, Puay-Yoke; Kayserili, Hülya; Al-Gazali, Lihadh; Shahwan, Monzer; Brancati, Francesco; Lee, Hane; O'Connor, Brian D; Schmidt-von Kegler, Mareen; Merriman, Barry; Nelson, Stanley F; Masri, Amira; Alkazaleh, Fawaz; Guerra, Deanna; Ferrari, Paola; Nanda, Arti; Rajab, Anna; Markie, David; Gray, Mary; Nelson, John; Grix, Arthur; Sommer, Annemarie; Savarirayan, Ravi; Janecke, Andreas R; Steichen, Elisabeth; Sillence, David; Hausser, Ingrid; Budde, Birgit; Nürnberg, Gudrun; Nürnberg, Peter; Seemann, Petra; Kunkel, Désirée; Zambruno, Giovanna; Dallapiccola, Bruno; Schuelke, Markus; Robertson, Stephen; Hamamy, Hanan; Wollnik, Bernd; Van Maldergem, Lionel; Mundlos, Stefan; Kornak, Uwe

    2009-09-01

    Autosomal recessive cutis laxa (ARCL) describes a group of syndromal disorders that are often associated with a progeroid appearance, lax and wrinkled skin, osteopenia and mental retardation. Homozygosity mapping in several kindreds with ARCL identified a candidate region on chromosome 17q25. By high-throughput sequencing of the entire candidate region, we detected disease-causing mutations in the gene PYCR1. We found that the gene product, an enzyme involved in proline metabolism, localizes to mitochondria. Altered mitochondrial morphology, membrane potential and increased apoptosis rate upon oxidative stress were evident in fibroblasts from affected individuals. Knockdown of the orthologous genes in Xenopus and zebrafish led to epidermal hypoplasia and blistering that was accompanied by a massive increase of apoptosis. Our findings link mutations in PYCR1 to altered mitochondrial function and progeroid changes in connective tissues.

  10. Two novel SCN9A mutations causing insensitivity to pain.

    Science.gov (United States)

    Nilsen, K B; Nicholas, A K; Woods, C G; Mellgren, S I; Nebuchennykh, M; Aasly, J

    2009-05-01

    The sensation of pain is important and there may be serious consequences if it is missing. Recently, the genetic basis for a channelopathy characterised by a congenital inability to experience pain has been described and channelopathy-associated insensitivity to pain has been proposed as a suitable name for this condition. Different mutations in the SCN9A gene causing loss of function of the voltage-gated sodium channel Nav1.7 have been reported in patients with this rare disease. Here we describe a woman with insensitivity to pain with two novel mutations in the SCN9A gene, coding for the Nav1.7 channel. We also discuss the finding of anosmia which apparently is a common feature in these patients.

  11. Mutations in ALDH1A3 cause microphthalmia.

    Science.gov (United States)

    Aldahmesh, M A; Khan, A O; Hijazi, H; Alkuraya, F S

    2013-08-01

    Microphthalmia is an important inborn error of eye development that can be associated with multisystem involvement. Anophthalmia is more severe and rarer. Single mutations in an expanding list of genes are known to cause this spectrum of anomaly. In one branch of a multiplex family with microphthalmia and anophthalmia, autozygome analysis excluded all known microphthalmia genes at the time of doing this study. Exome sequencing and autozygome filtration identified a novel homozygous variant in ALDH1A3. Subsequently, we identified another homozygous variant in 2 of the 10 probands with microphthalmia we specifically screened for mutations in ALDH1A3. Interestingly, the other branch of the original family was found to segregate anophthalmia/syndactyly with a novel homozygous SMOC1 variant. Our data support the very recent and independent identification of ALDH1A3 as a disease gene in microphthalmia. Locus heterogeneity should be considered in consanguineous families even for extremely rare phenotypes.

  12. Diseases caused by mutations in ORAI1 and STIM1

    Science.gov (United States)

    Lacruz, Rodrigo S.; Feske, Stefan

    2015-01-01

    Ca2+ release-activated Ca2+ (CRAC) channels mediate a specific form of Ca2+ influx called store-operated Ca2+ entry (SOCE) that contributes to the function of many cell types. CRAC channels are formed by ORAI1 proteins located in the plasma membrane, which form its ion-conducting pore. ORAI1 channels are activated by stromal interaction molecule (STIM) 1 and STIM2 located in the endoplasmic reticulum. Loss- and gain-of-function gene mutations in ORAI1 and STIM1 in human patients cause distinct disease syndromes. CRAC channelopathy is caused by loss-of-function mutations in ORAI1 and STIM1 that abolish CRAC channel function and SOCE; it is characterized by severe combined immunodeficiency (SCID)-like disease, autoimmunity, muscular hypotonia, and ectodermal dysplasia, with defects in dental enamel. The latter defect emphasizes an important role of CRAC channels in tooth development. By contrast, autosomal dominant gain-of-function mutations in these genes result in constitutive CRAC channel activation, SOCE, and increased intracellular Ca2+ levels that are associated with an overlapping spectrum of diseases, including non-syndromic tubular aggregate myopathy (TAM) and York platelet and Stormorken syndromes, two syndromes defined, besides myopathy, by thrombocytopenia, thrombopathy, and bleeding diathesis. The fact that myopathy results from loss- and gain-of-function mutations in ORAI1 and STIM1 highlights the importance of CRAC channels for Ca2+ homeostasis in skeletal muscle function. The cellular dysfunction and clinical disease spectrum observed in mutant patients provide important information about the molecular regulation of ORAI1 and STIM1 proteins and the role of CRAC channels in human physiology. PMID:26469693

  13. Homozygous Nonsense Mutations in TWIST2 Cause Setleis Syndrome

    Science.gov (United States)

    Tukel, Turgut; Šošić, Dražen; Al-Gazali, Lihadh I.; Erazo, Mónica; Casasnovas, Jose; Franco, Hector L.; Richardson, James A.; Olson, Eric N.; Cadilla, Carmen L.; Desnick, Robert J.

    2010-01-01

    The focal facial dermal dysplasias (FFDDs) are a group of inherited developmental disorders in which the characteristic diagnostic feature is bitemporal scar-like lesions that resemble forceps marks. To date, the genetic defects underlying these ectodermal dysplasias have not been determined. To identify the gene defect causing autosomal-recessive Setleis syndrome (type III FFDD), homozygosity mapping was performed with genomic DNAs from five affected individuals and 26 members of the consanguineous Puerto Rican (PR) family originally described by Setleis and colleagues. Microsatellites D2S1397 and D2S2968 were homozygous in all affected individuals, mapping the disease locus to 2q37.3. Haplotype analyses of additional markers in the PR family and a consanguineous Arab family further limited the disease locus to ∼3 Mb between D2S2949 and D2S2253. Of the 29 candidate genes in this region, the bHLH transcription factor, TWIST2, was initially sequenced on the basis of its known involvement in murine facial development. Homozygous TWIST2 nonsense mutations, c.324C>T and c.486C>T, were identified in the affected members of the Arab and PR families, respectively. Characterization of the expressed mutant proteins, p.Q65X and p.Q119X, by electrophoretic mobility shift assays and immunoblot analyses indicated that they were truncated and unstable. Notably, Setleis syndrome patients and Twist2 knockout mice have similar facial features, indicating the gene's conserved role in mammalian development. Although human TWIST2 and TWIST1 encode highly homologous bHLH transcription factors, the finding that TWIST2 recessive mutations cause an FFDD and dominant TWIST1 mutations cause Saethre-Chotzen craniocynostosis suggests that they function independently in skin and bone development. PMID:20691403

  14. Niemann-Pick type C mutations cause lipid traffic jam.

    Science.gov (United States)

    Liscum, L

    2000-03-01

    The Niemann-Pick C protein (NPC1) is required for cholesterol transport from late endosomes and lysosomes to other cellular membranes. Mutations in NPC1 cause lysosomal lipid storage and progressive neurological degeneration. Cloning of the NPC1 gene has given us tools with which to investigate the function of this putative cholesterol transporter. Here, we discuss recent studies indicating that NPC1 is not a cholesterol-specific transport molecule. Instead, NPC1 appears to be required for the vesicular shuttling of both lipids and fluid-phase constituents from multivesicular late endosomes to destinations such as the trans-Golgi network.

  15. LAMB3 mutations causing autosomal-dominant amelogenesis imperfecta.

    Science.gov (United States)

    Kim, J W; Seymen, F; Lee, K E; Ko, J; Yildirim, M; Tuna, E B; Gencay, K; Shin, T J; Kyun, H K; Simmer, J P; Hu, J C-C

    2013-10-01

    Amelogenesis imperfecta (AI) can be either isolated or part of a larger syndrome. Junctional epidermolysis bullosa (JEB) is a collection of autosomal-recessive disorders featuring AI associated with skin fragility and other symptoms. JEB is a recessive syndrome usually caused by mutations in both alleles of COL17A1, LAMA3, LAMB3, or LAMC2. In rare cases, heterozygous carriers in JEB kindreds display enamel malformations in the absence of skin fragility (isolated AI). We recruited two kindreds with autosomal-dominant amelogenesis imperfecta (ADAI) characterized by generalized severe enamel hypoplasia with deep linear grooves and pits. Whole-exome sequencing of both probands identified novel heterozygous mutations in the last exon of LAMB3 that likely truncated the protein. The mutations perfectly segregated with the enamel defects in both families. In Family 1, an 8-bp deletion (c.3446_3453del GACTGGAG) shifted the reading frame (p.Gly 1149Glufs*8). In Family 2, a single nucleotide substitution (c.C3431A) generated an in-frame translation termination codon (p.Ser1144*). We conclude that enamel formation is particularly sensitive to defects in hemidesmosome/basement-membrane complexes and that syndromic and non-syndromic forms of AI can be etiologically related.

  16. Ccdc66 null mutation causes retinal degeneration and dysfunction.

    Science.gov (United States)

    Gerding, Wanda M; Schreiber, Sabrina; Schulte-Middelmann, Tobias; de Castro Marques, Andreia; Atorf, Jenny; Akkad, Denis A; Dekomien, Gabriele; Kremers, Jan; Dermietzel, Rolf; Gal, Andreas; Rülicke, Thomas; Ibrahim, Saleh; Epplen, Jörg T; Petrasch-Parwez, Elisabeth

    2011-09-15

    Retinitis pigmentosa (RP) is a group of human retinal disorders, with more than 100 genes involved in retinal degeneration. Canine and murine models are useful for investigating human RP based on known, naturally occurring mutations. In Schapendoes dogs, for example, a mutation in the CCDC66 gene has been shown to cause autosomal recessively inherited, generalized progressive retinal atrophy (gPRA), the canine counterpart to RP. Here, a novel mouse model with a disrupted Ccdc66 gene was investigated to reveal the function of protein CCDC66 and the pathogenesis of this form of gPRA. Homozygous Ccdc66 mutant mice lack retinal Ccdc66 RNA and protein expression. Light and electron microscopy reveal an initial degeneration of photoreceptors already at 13 days of age, followed by a slow, progressive retinal degeneration over months. Retinal dysfunction causes reduced scotopic a-wave amplitudes, declining from 1 to 7 months of age as well as an early reduction of the photopic b-wave at 1 month, improving slightly at 7 months, as evidenced by electroretinography. In the retina of the wild-type (WT) mouse, protein CCDC66 is present at highest levels after birth, followed by a decline until adulthood, suggesting a crucial role in early development. Protein CCDC66 is expressed predominantly in the developing rod outer segments as confirmed by subcellular analyses. These findings illustrate that the lack of protein CCDC66 causes early, slow progressive rod-cone dysplasia in the novel Ccdc66 mutant mouse model, thus providing a sound foundation for the development of therapeutic strategies.

  17. RTTN Mutations Cause Primary Microcephaly and Primordial Dwarfism in Humans.

    Science.gov (United States)

    Shamseldin, Hanan; Alazami, Anas M; Manning, Melanie; Hashem, Amal; Caluseiu, Oana; Tabarki, Brahim; Esplin, Edward; Schelley, Susan; Innes, A Micheil; Parboosingh, Jillian S; Lamont, Ryan; Majewski, Jacek; Bernier, Francois P; Alkuraya, Fowzan S

    2015-12-03

    Primary microcephaly is a developmental brain anomaly that results from defective proliferation of neuroprogenitors in the germinal periventricular zone. More than a dozen genes are known to be mutated in autosomal-recessive primary microcephaly in isolation or in association with a more generalized growth deficiency (microcephalic primordial dwarfism), but the genetic heterogeneity is probably more extensive. In a research protocol involving autozygome mapping and exome sequencing, we recruited a multiplex consanguineous family who is affected by severe microcephalic primordial dwarfism and tested negative on clinical exome sequencing. Two candidate autozygous intervals were identified, and the second round of exome sequencing revealed a single intronic variant therein (c.2885+8A>G [p.Ser963(∗)] in RTTN exon 23). RT-PCR confirmed that this change creates a cryptic splice donor and thus causes retention of the intervening 7 bp of the intron and leads to premature truncation. On the basis of this finding, we reanalyzed the exome file of a second consanguineous family affected by a similar phenotype and identified another homozygous change in RTTN as the likely causal mutation. Combined linkage analysis of the two families confirmed that RTTN maps to the only significant linkage peak. Finally, through international collaboration, a Canadian multiplex family affected by microcephalic primordial dwarfism and biallelic mutation of RTTN was identified. Our results expand the phenotype of RTTN-related disorders, hitherto limited to polymicrogyria, to include microcephalic primordial dwarfism with a complex brain phenotype involving simplified gyration. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. De novo mutations in ATP1A3 cause alternating hemiplegia of childhood

    DEFF Research Database (Denmark)

    Heinzen, Erin L; Swoboda, Kathryn J; Hitomi, Yuki

    2012-01-01

    in a case of familial AHC. Notably, most AHC cases are caused by one of seven recurrent ATP1A3 mutations, one of which was observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset dystonia-parkinsonism, AHC-causing mutations in this gene caused consistent reductions in ATPase activity without...... affecting the level of protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in ATP1A3....

  19. MAX mutations cause hereditary and sporadic pheochromocytoma and paraganglioma

    NARCIS (Netherlands)

    Burnichon, N.; Cascon, A.; Schiavi, F.; Morales, N.P.; Comino-Mendez, I.; Abermil, N.; Inglada-Perez, L.; Cubas, A.A. de; Amar, L.; Barontini, M.; Quiros, S.B. de; Bertherat, J.; Bignon, Y.J.; Blok, M.J.; Bobisse, S.; Borrego, S.; Castellano, M.; Chanson, P.; Chiara, M.D.; Corssmit, E.P.; Giacche, M.; Krijger, R.R. de; Ercolino, T.; Girerd, X.; Gomez-Garcia, E.B.; Gomez-Grana, A.; Guilhem, I.; Hes, F.J.; Honrado, E.; Korpershoek, E.; Lenders, J.W.; Leton, R.; Mensenkamp, A.R.; Merlo, A.; Mori, L.; Murat, A.; Pierre, P.; Plouin, P.F.; Prodanov, T.; Quesada-Charneco, M.; Qin, N.; Rapizzi, E.; Raymond, V.; Reisch, N.; Roncador, G.; Ruiz-Ferrer, M.; Schillo, F.; Stegmann, A.P.; Suarez, C.; Taschin, E.; Timmers, H.J.L.M.; Tops, C.M.; Urioste, M.; Beuschlein, F.; Pacak, K.; Mannelli, M.; Dahia, P.L.; Opocher, G.; Eisenhofer, G.; Gimenez-Roqueplo, A.P.; Robledo, M.

    2012-01-01

    PURPOSE: Pheochromocytomas (PCC) and paragangliomas (PGL) are genetically heterogeneous neural crest-derived neoplasms. Recently we identified germline mutations in a new tumor suppressor susceptibility gene, MAX (MYC-associated factor X), which predisposes carriers to PCC. How MAX mutations

  20. Novel Mutations and Mutation Combinations of TMPRSS3 Cause Various Phenotypes in One Chinese Family with Autosomal Recessive Hearing Impairment

    Science.gov (United States)

    Wang, Guo-Jian; Xu, Jin-Cao; Su, Yu

    2017-01-01

    Autosomal recessive hearing impairment with postlingual onset is rare. Exceptions are caused by mutations in the TMPRSS3 gene, which can lead to prelingual (DFNB10) as well as postlingual deafness (DFNB8). TMPRSS3 mutations can be classified as mild or severe, and the phenotype is dependent on the combination of TMPRSS3 mutations. The combination of two severe mutations leads to profound hearing impairment with a prelingual onset, whereas severe mutations in combination with milder TMPRSS3 mutations lead to a milder phenotype with postlingual onset. We characterized a Chinese family (number FH1523) with not only prelingual but also postlingual hearing impairment. Three mutations in TMPRSS3, one novel mutation c.36delC [p.(Phe13Serfs⁎12)], and two previously reported pathogenic mutations, c.916G>A (p.Ala306Thr) and c.316C>T (p.Arg106Cys), were identified. Compound heterozygous mutations of p.(Phe13Serfs⁎12) and p.Ala306Thr manifest as prelingual, profound hearing impairment in the patient (IV: 1), whereas the combination of p.Arg106Cys and p.Ala306Thr manifests as postlingual, milder hearing impairment in the patient (II: 2, II: 3, II: 5), suggesting that p.Arg106Cys mutation has a milder effect than p.(Phe13Serfs⁎12). We concluded that different combinations of TMPRSS3 mutations led to different hearing impairment phenotypes (DFNB8/DFNB10) in this family. PMID:28246597

  1. Exome Sequencing Reveals Cubilin Mutation as a Single-Gene Cause of Proteinuria

    OpenAIRE

    Ovunc, Bugsu; Otto, Edgar A.; Vega-Warner, Virginia; Saisawat, Pawaree; Ashraf, Shazia; Ramaswami, Gokul; Fathy, Hanan M.; Schoeb, Dominik; Chernin, Gil; Lyons, Robert H.; Engin YILMAZ; Hildebrandt, Friedhelm

    2011-01-01

    In two siblings of consanguineous parents with intermittent nephrotic-range proteinuria, we identified a homozygous deleterious frameshift mutation in the gene CUBN, which encodes cubulin, using exome capture and massively parallel re-sequencing. The mutation segregated with affected members of this family and was absent from 92 healthy individuals, thereby identifying a recessive mutation in CUBN as the single-gene cause of proteinuria in this sibship. Cubulin mutations cause a hereditary fo...

  2. 5'UTR mutations of ENG cause hereditary hemorrhagic telangiectasia.

    Science.gov (United States)

    Damjanovich, Kristy; Langa, Carmen; Blanco, Francisco J; McDonald, Jamie; Botella, Luisa M; Bernabeu, Carmelo; Wooderchak-Donahue, Whitney; Stevenson, David A; Bayrak-Toydemir, Pinar

    2011-12-22

    Hereditary hemorrhagic telangiectasia (HHT) is a vascular disorder characterized by epistaxis, arteriovenous malformations, and telangiectases. The majority of the patients have a mutation in the coding region of the activin A receptor type II-like 1 (ACVRL1) or Endoglin (ENG) gene. However, in approximately 15% of cases, sequencing analysis and deletion/duplication testing fail to identify mutations in the coding regions of these genes. Knowing its vital role in transcription and translation control, we were prompted to investigate the 5'untranslated region (UTR) of ENG. We sequenced the 5'UTR of ENG for 154 HHT patients without mutations in ENG or ACVRL1 coding regions. We found a mutation (c.-127C > T), which is predicted to affect translation initiation and alter the reading frame of endoglin. This mutation was found in a family with linkage to the ENG, as well as in three other patients, one of which had an affected sibling with the same mutation. In vitro expression studies showed that a construct with the c.-127C > T mutation alters the translation and decreases the level of the endoglin protein. In addition, a c.-9G > A mutation was found in three patients, one of whom was homozygous for this mutation. Expression studies showed decreased protein levels suggesting that the c.-9G > A is a hypomorphic mutation. Our results emphasize the need for the inclusion of the 5'UTR region of ENG in clinical testing for HHT.

  3. Asparaginase II of Saccharomyces cerevisiae: selection of four mutations that cause derepressed enzyme synthesis.

    Science.gov (United States)

    Kamerud, J Q; Roon, R J

    1986-01-01

    A positive selection method was used to isolate four Saccharomyces cerevisiae mutations that cause derepressed synthesis of asparaginase II. The four mutations (and1, and2, and3, and4) were neither closely linked to each other nor linked to previously characterized mutations (asp3, asp6) which cause the complete loss of asparaginase II activity. One of the new mutations (and4) was shown to be allelic to gdh-CR, a pleiotropic mutation which causes derepressed synthesis of a number of enzymes of nitrogen catabolism.

  4. Recessive mutations in DGKE cause atypical hemolytic-uremic syndrome

    Science.gov (United States)

    Lemaire, Mathieu; Frémeaux-Bacchi, Véronique; Schaefer, Franz; Choi, Murim; Tang, Wai Ho; Le Quintrec, Moglie; Fakhouri, Fadi; Taque, Sophie; Nobili, François; Martinez, Frank; Ji, Weizhen; Overton, John D.; Mane, Shrikant M.; Nürnberg, Gudrun; Altmüller, Janine; Thiele, Holger; Morin, Denis; Deschenes, Georges; Baudouin, Véronique; Llanas, Brigitte; Collard, Laure; Majid, Mohammed A.; Simkova, Eva; Nürnberg, Peter; Rioux-Leclerc, Nathalie; Moeckel, Gilbert W.; Gubler, Marie Claire; Hwa, John; Loirat, Chantal; Lifton, Richard P.

    2013-01-01

    Pathologic thrombosis is a major cause of mortality. Hemolytic-uremic syndrome (HUS) features episodes of small vessel thrombosis resulting in microangiopathic hemolytic anemia, thrombocytopenia and renal failure1. Atypical HUS (aHUS) can result from genetic or autoimmune factors2 that lead to pathologic complement cascade activation3. By exome sequencing we identify recessive mutations in DGKE (diacylglycerol kinase epsilon) that co-segregate with aHUS in 9 unrelated kindreds, defining a distinctive Mendelian disease. Affected patients present with aHUS before age 1, have persistent hypertension, hematuria and proteinuria (sometimes nephrotic range), and develop chronic kidney disease with age. DGKE is found in endothelium, platelets, and podocytes. Arachidonic acid-containing diacylglycerols (DAG) activate protein kinase C, which promotes thrombosis. DGKE normally inactivates DAG signaling. We infer that loss of DGKE function results in a pro-thrombotic state. These findings identify a new mechanism of pathologic thrombosis and kidney failure and have immediate implications for treatment of aHUS patients. PMID:23542698

  5. Oxidative Stress in Dilated Cardiomyopathy Caused by MYBPC3 Mutation

    NARCIS (Netherlands)

    T.L. Lynch (Thomas L.); M. Sivaguru (Mayandi); M. Velayutham (Murugesan); A.J. Cardounel (Arturo J.); M. Michels (Michelle); D. Barefield (David); S. Govindan (Suresh); C.D. Remedios (Cristobal Dos); J. van der Velden (Jolanda); S. Sadayappan (Sakthivel)

    2015-01-01

    textabstractCardiomyopathies can result from mutations in genes encoding sarcomere proteins including MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C). However, whether oxidative stress is augmented due to contractile dysfunction and cardiomyocyte damage in MYBPC3-mutated cardiomyopa

  6. Mutations in PCBD1 Cause Hypomagnesemia and Renal Magnesium Wasting

    NARCIS (Netherlands)

    Ferre, S.; Baaij, J.H.F. de; Ferreira, P.; Germann, R.; Klerk, J.B. De; Lavrijsen, M.; Zeeland, F. van; Venselaar, H.; Kluijtmans, L.A.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2014-01-01

    Mutations in PCBD1 are causative for transient neonatal hyperphenylalaninemia and primapterinuria (HPABH4D). Until now, HPABH4D has been regarded as a transient and benign neonatal syndrome without complications in adulthood. In our study of three adult patients with homozygous mutations in the PCBD

  7. A NOVEL KCNA1 MUTATION CAUSING EPISODIC ATAXIA TYPE I

    NARCIS (Netherlands)

    Lassche, Saskia; Lainez, Sergio; Bloem, Bastiaan R.; van de Warrenburg, Bart P. C.; Hofmeijer, Jeannette; Lemmink, Henny H.; Hoenderop, Joost G. J.; Bindels, Rene J. M.; Drost, Gea

    2014-01-01

    We describe the clinical phenotype of a novel de novo KNCA1 mutation, and functional characterization of the effects of the mutation on Kv1.1 channel function. HEK293 cells were transfected transiently with either wild-type or mutant channels. Representative currents were evoked after application of

  8. MAX mutations cause hereditary and sporadic pheochromocytoma and paraganglioma

    NARCIS (Netherlands)

    N. Burnichon (Nelly); A. Cascoń (Alberto); F. Schiavi (Francesca); N. Morales (NicolePaes); I. Comino-Méndez (Iñaki); N. Abermil (Nasséra); L. Inglada-Pérez (Lucía); A.A. de Cubas (Aguirre); L. Amar (Laurence); M. Barontini (Marta); S.B. de Quiroś (Sandra Bernaldo); J. Bertherat (Jerome); Y.-J. Bignon (Yves-Jean); M.J. Blok (Marinus); S. Bobisse (Sara); S. Borrego (Salud); M. Castellano (Maurizio); P. Chanson (Philippe); A. de Chiara; E.P. Corssmit (Eleonora); M. Giacchè (Mara); R.R. de Krijger (Ronald); T. Ercolino (Tonino); X. Girerd (Xavier); E.B. Gómez García (Encarna); Á. Gómez-Graña (Álvaro); I. Guilhem (Isabelle); F.J. Hes (Frederik); E. Honrado (Emiliano); E. Korpershoek (Esther); J.W. Lenders (Jacques); R. Letón (Rocío); A.R. Mensenkamp (Arjen); A. Merlo (Anna); L. Mori (Luigi); A. Murat (Arnaud); P. Pierre (Peggy); P.F. Plouin (Pierre-Franco̧is); T. Prodanov (Tamara); M. Quesada-Charneco (Miguel); N. Qin (Nan); E. Rapizzi (Elena); E. Raymond (Eric); N. Reisch (Nicole); G. Roncador (Giovanna); M. Ruiz-Ferrer (Macarena); F. Schillo (Frank); A.P.A. Stegmann (Sander); C. Suarez (Carlos); E. Taschin (Elisa); H.J.L.M. Timmers; C. Tops (Carli); M. Urioste (Miguel); F. Beuschlein (Felix); K. Pacak (Karel); M. Mannelli (Massimo); P.L. Dahia (Patricia); G. Opocher (Giuseppe); G. Eisenhofer (Graeme); A.P. Gimenez-Roqueplo; M. Robledo (Mercedes)

    2012-01-01

    textabstractPurpose: Pheochromocytomas (PCC) and paragangliomas (PGL) are genetically heterogeneous neural crest-derived neoplasms. Recently we identified germline mutations in a new tumor suppressor susceptibility gene, MAX (MYC-associated factor X), which predisposes carriers to PCC. How MAX mutat

  9. Dominant missense mutations in ABCC9 cause Cantu syndrome

    NARCIS (Netherlands)

    Harakalova, M.; van Harssel, J.J.; Terhal, P.A.; van Lieshout, S.; Duran, K.; Renkens, I.; Amor, D.J.; Wilson, L.C.; Kirk, E.P.; Turner, C.L.; Shears, D.; Garcia-Minaur, S.; Lees, M.M.; Ross, A.; Venselaar, H.; Vriend, G.; Takanari, H.; Rook, M.B.; van der Heyden, M.A.; Asselbergs, F.W.; Breur, H.M.; Swinkels, M.E.; Scurr, I.J.; Smithson, S.F.; Knoers, N.V.; van der Smagt, J.J.; Nijman, I.J.; Kloosterman, W.P.; van Haelst, M.M.; van Haaften, G.; Cuppen, E.

    2012-01-01

    Cantu syndrome is characterized by congenital hypertrichosis, distinctive facial features, osteochondrodysplasia and cardiac defects. By using family-based exome sequencing, we identified a de novo mutation in ABCC9. Subsequently, we discovered novel dominant missense mutations in ABCC9 in 14 of the

  10. Dominant missense mutations in ABCC9 cause Cantu syndrome.

    NARCIS (Netherlands)

    Harakalova, M.; Harssel, J.J. van; Terhal, P.A.; Lieshout, S. van; Duran, K.; Renkens, I.; Amor, D.J.; Wilson, L.C.; Kirk, E.P.; Turner, C.L.; Shears, D.; Garcia-Minaur, S.; Lees, M.M.; Ross, A.; Venselaar, H.; Vriend, G.; Takanari, H.; Rook, M.B.; Heyden, M.A. van der; Asselbergs, F.W.; Breur, H.M.; Swinkels, M.E.; Scurr, I.J.; Smithson, S.F.; Knoers, N.V.A.M.; Smagt, J.J. van der; Nijman, I.J.; Kloosterman, W.P.; Haelst, M.M. van; Haaften, G. van; Cuppen, E.

    2012-01-01

    Cantu syndrome is characterized by congenital hypertrichosis, distinctive facial features, osteochondrodysplasia and cardiac defects. By using family-based exome sequencing, we identified a de novo mutation in ABCC9. Subsequently, we discovered novel dominant missense mutations in ABCC9 in 14 of the

  11. A NOVEL KCNA1 MUTATION CAUSING EPISODIC ATAXIA TYPE I

    NARCIS (Netherlands)

    Lassche, Saskia; Lainez, Sergio; Bloem, Bastiaan R.; van de Warrenburg, Bart P. C.; Hofmeijer, Jeannette; Lemmink, Henny H.; Hoenderop, Joost G. J.; Bindels, Rene J. M.; Drost, Gea

    2014-01-01

    We describe the clinical phenotype of a novel de novo KNCA1 mutation, and functional characterization of the effects of the mutation on Kv1.1 channel function. HEK293 cells were transfected transiently with either wild-type or mutant channels. Representative currents were evoked after application of

  12. A novel KCNA1 mutation causing episodic ataxia type I

    NARCIS (Netherlands)

    Lassche, S.; Lainez, S.; Bloem, B.R.; Warrenburg, B.P.C. van de; Hofmeijer, J.; Lemmink, H.H.; Hoenderop, J.G.; Bindels, R.J.M.; Drost, G.

    2014-01-01

    We describe the clinical phenotype of a novel de novo KNCA1 mutation, and functional characterization of the effects of the mutation on Kv1.1 channel function. HEK293 cells were transfected transiently with either wild-type or mutant channels. Representative currents were evoked after application of

  13. Lynch Syndrome Caused by Germline PMS2 Mutations

    DEFF Research Database (Denmark)

    Ten Broeke, Sanne W; Brohet, Richard M; Tops, Carli M

    2015-01-01

    . Standardized incidence ratios (SIRs) were calculated to estimate risks for other Lynch syndrome-associated cancers. RESULTS: The cumulative risk (CR) of CRC for male mutation carriers by age 70 years was 19%. The CR among female carriers was 11% for CRC and 12% for EC. The mean age of CRC development was 52......PURPOSE: The clinical consequences of PMS2 germline mutations are poorly understood compared with other Lynch-associated mismatch repair gene (MMR) mutations. The aim of this European cohort study was to define the cancer risk faced by PMS2 mutation carriers. METHODS: Data were collected from 98...... years, and there was a significant difference in mean age of CRC between the probands (mean, 47 years; range, 26 to 68 years) and other family members with a PMS2 mutation (mean, 58 years; range, 31 to 86 years; P

  14. Pyridoxine responsive epilepsy caused by a novel homozygous PNPO mutation

    Directory of Open Access Journals (Sweden)

    B. Jaeger

    2016-03-01

    Full Text Available We report a patient with anti-epileptic treatment refractory neonatal seizures responsive to pyridoxine. Biochemical analysis revealed normal markers for antiquitin deficiency and also mutation analysis of the ALDH7A1 (Antiquitin gene was negative. Mutation analysis of the PNPO gene revealed a novel, homozygous, presumed pathogenic mutation (c.481C>T; p.(Arg161Cys. Measurements of B6 vitamers in a CSF sample after pyridoxine administration revealed elevated pyridoxamine as the only metabolic marker for PNPO deficiency. With pyridoxine monotherapy the patient is seizure free and neurodevelopmental outcome at the age of 14 months is normal.

  15. Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death

    DEFF Research Database (Denmark)

    Nyegaard, Mette; Overgaard, Michael Toft; Søndergaard, Mads

    2012-01-01

    a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe...... dominantly inherited form of CPVT-like arrhythmias, we mapped the disease locus to chromosome 14q31-32. Sequencing CALM1 encoding calmodulin revealed a heterozygous missense mutation (c.161A>T [p.Asn53Ile]) segregating with the disease. A second, de novo, missense mutation (c.293A>G [p.Asn97Ser......]) was subsequently identified in an individual of Iraqi origin; this individual was diagnosed with CPVT from a screening of 61 arrhythmia samples with no identified RYR2 mutations. Both CALM1 substitutions demonstrated compromised calcium binding, and p.Asn97Ser displayed an aberrant interaction with the RYR2...

  16. Mutations in LTBP3 cause acromicric dysplasia and geleophysic dysplasia.

    Science.gov (United States)

    McInerney-Leo, Aideen M; Le Goff, Carine; Leo, Paul J; Kenna, Tony J; Keith, Patricia; Harris, Jessica E; Steer, Ruth; Bole-Feysot, Christine; Nitschke, Patrick; Kielty, Cay; Brown, Matthew A; Zankl, Andreas; Duncan, Emma L; Cormier-Daire, Valerie

    2016-07-01

    Acromelic dysplasias are a group of disorders characterised by short stature, brachydactyly, limited joint extension and thickened skin and comprises acromicric dysplasia (AD), geleophysic dysplasia (GD), Myhre syndrome and Weill-Marchesani syndrome. Mutations in several genes have been identified for these disorders (including latent transforming growth factor β (TGF-β)-binding protein-2 (LTBP2), ADAMTS10, ADAMSTS17 and fibrillin-1 (FBN1) for Weill-Marchesani syndrome, ADAMTSL2 for recessive GD and FBN1 for AD and dominant GD), encoding proteins involved in the microfibrillar network. However, not all cases have mutations in these genes. Individuals negative for mutations in known acromelic dysplasia genes underwent whole exome sequencing. A heterozygous missense mutation (exon 14: c.2087C>G: p.Ser696Cys) in latent transforming growth factor β (TGF-β)-binding protein-3 (LTBP3) was identified in a dominant AD family. Two distinct de novo heterozygous LTPB3 mutations were also identified in two unrelated GD individuals who had died in early childhood from respiratory failure-a donor splice site mutation (exon 12 c.1846+5G>A) and a stop-loss mutation (exon 28: c.3912A>T: p.1304*Cysext*12). The constellation of features in these AD and GD cases, including postnatal growth retardation of long bones and lung involvement, is reminiscent of the null ltbp3 mice phenotype. We conclude that LTBP3 is a novel component of the microfibrillar network involved in the acromelic dysplasia spectrum. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  17. Oxidative Stress in Dilated Cardiomyopathy Caused by MYBPC3 Mutation

    Directory of Open Access Journals (Sweden)

    Thomas L. Lynch

    2015-01-01

    Full Text Available Cardiomyopathies can result from mutations in genes encoding sarcomere proteins including MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C. However, whether oxidative stress is augmented due to contractile dysfunction and cardiomyocyte damage in MYBPC3-mutated cardiomyopathies has not been elucidated. To determine whether oxidative stress markers were elevated in MYBPC3-mutated cardiomyopathies, a previously characterized 3-month-old mouse model of dilated cardiomyopathy (DCM expressing a homozygous MYBPC3 mutation (cMyBP-C(t/t was used, compared to wild-type (WT mice. Echocardiography confirmed decreased percentage of fractional shortening in DCM versus WT hearts. Histopathological analysis indicated a significant increase in myocardial disarray and fibrosis while the second harmonic generation imaging revealed disorganized sarcomeric structure and myocyte damage in DCM hearts when compared to WT hearts. Intriguingly, DCM mouse heart homogenates had decreased glutathione (GSH/GSSG ratio and increased protein carbonyl and lipid malondialdehyde content compared to WT heart homogenates, consistent with elevated oxidative stress. Importantly, a similar result was observed in human cardiomyopathy heart homogenate samples. These results were further supported by reduced signals for mitochondrial semiquinone radicals and Fe-S clusters in DCM mouse hearts measured using electron paramagnetic resonance spectroscopy. In conclusion, we demonstrate elevated oxidative stress in MYPBC3-mutated DCM mice, which may exacerbate the development of heart failure.

  18. A novel mutation in PIGW causes glycosylphosphatidylinositol deficiency without hyperphosphatasia.

    Science.gov (United States)

    Hogrebe, Max; Murakami, Yoshiko; Wild, Martin; Ahlmann, Martina; Biskup, Saskia; Hörtnagel, Konstanze; Grüneberg, Marianne; Reunert, Janine; Linden, Tobias; Kinoshita, Taroh; Marquardt, Thorsten

    2016-12-01

    In recent years, many mutations have been identified that affect the biosynthesis of the glycosylphosphatidylinositol anchor, a biomolecule that attaches surface molecules to cell membranes. Here, we present two second-degree cousins with unexplained patterns of seizures. Next-generation sequencing identified the homozygous c.460A>G; p.(R154G) PIGW mutation in both patients. Transfection of the mutated allele into Pigw-defective CHO cells indicated impaired enzymatic activity of the mutated PIGW product. Alkaline phosphatase did not exceed the upper normal range and flow cytometry of CD16, CD24, and CD66c on granulocytes showed subtle changes of the cellular expression of the glycosylphosphatidylinositol-anchored proteins. The patients' phenotype is therefore remarkably different from the phenotype of the only other described individual with PIGW mutations. Patients might therefore be missed when relying on traditional flow cytometry of glycosylphosphatidylinositol-anchored proteins only and we suggest that glycosylphosphatidylinositol-deficiency should be considered even with patients not showing the typical clinical phenotypes. © 2016 Wiley Periodicals, Inc.

  19. De Novo GMNN Mutations Cause Autosomal-Dominant Primordial Dwarfism Associated with Meier-Gorlin Syndrome

    NARCIS (Netherlands)

    Burrage, L.C.; Charng, W.L.; Eldomery, M.K.; Willer, J.R.; Davis, E.E.; Lugtenberg, D.; Zhu, W.; Leduc, M.S.; Akdemir, Z.C.; Azamian, M.; Zapata, G.; Hernandez, P.P.; Schoots, J.; Munnik, S.A. de; Roepman, R.; Pearring, J.N.; Jhangiani, S.; Katsanis, N.; Vissers, L.E.L.M.; Brunner, H.G.; Beaudet, A.L.; Rosenfeld, J.A.; Muzny, D.M.; Gibbs, R.A.; Eng, C.M.; Xia, F.; Lalani, S.R.; Lupski, J.R.; Bongers, E.M.H.F.; Yang, Y

    2015-01-01

    Meier-Gorlin syndrome (MGS) is a genetically heterogeneous primordial dwarfism syndrome known to be caused by biallelic loss-of-function mutations in one of five genes encoding pre-replication complex proteins: ORC1, ORC4, ORC6, CDT1, and CDC6. Mutations in these genes cause disruption of the origin

  20. Mutations in PAX3 that cause Waardenburg syndrome type I: Ten new mutations and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, C.T.; Hoth, C.F.; Milunsky, A. [Boston Univ. School of Medicine, MA (United States)] [and others

    1995-08-28

    Waardenburg syndrome (WS) is an autosomal-dominant disorder characterized by sensorineural hearing loss, dystopia canthorum, and pigmentary disturbances, and it represents the most common form of inherited deafness in infants. WS type I is characterized by the presence of dystopia canthorum, while individuals with WS type II have normally-located canthi. WS type III is similar to WS type I but is also characterized by musculoskeletal abnormalities. Defects in the PAX3 gene, a transcription factor expressed during embryonic development, have been shown to cause WS types I and III in several families. In contrast, mutations in PAX3 do not cause WS type II, and linkage of the disease to other chromosomal regions has been demonstrated. We describe 10 additional mutations in the PAX3 gene in families with WS type I. Eight of these mutations are in the region of PAX3, where only one mutation has been previously described. These mutations, together with those previously reported, cover essentially the entire PAX3 gene and represent a wide spectrum of mutations that can cause WS type I. Thus far, all but one of the mutations are private; only one mutation has been reported in two apparently unrelated families. Our analysis thus far demonstrates little correlation between genotype and phenotype; deletions of the entire PAX3 gene result in phenotypes indistinguishable from those associated with single-base substitutions in the paired domain or homeodomain of PAX3. Moreover, two similar mutations in close proximity can result in significantly different phenotypes, WS type I in one family and WS type III in another. 47 refs., 3 figs., 5 tabs.

  1. Mutations in TMEM231 cause Meckel-Gruber syndrome.

    Science.gov (United States)

    Shaheen, Ranad; Ansari, Shinu; Mardawi, Elham Al; Alshammari, Muneera J; Alkuraya, Fowzan S

    2013-03-01

    Meckel-Gruber syndrome (MKS) is a genetically heterogeneous severe ciliopathy characterised by early lethality, occipital encephalocele, polydactyly, and polycystic kidney disease. To report genetic analysis results in two families in which all known MKS diseases genes have been excluded. In two consanguineous families with classical MKS in which autozygome-guided sequencing of previously reported MKS genes was negative, we performed exome sequencing followed by autozygome filtration. We identified one novel splicing mutation in TMEM231, which led to complete degradation of the mutant transcript in one family, and a novel missense mutation in the other, both in the homozygous state. TMEM231 represents a novel MKS locus. The very recent identification of TMEM231 mutations in Joubert syndrome supports the growing appreciation of the overlap in the molecular pathogenesis between these two ciliopathies.

  2. Mutations in TMEM231 cause Meckel–Gruber syndrome

    Science.gov (United States)

    Shaheen, Ranad; Ansari, Shinu; Mardawi, Elham AL; Alshammari, Muneera J; Alkuraya, Fowzan S

    2013-01-01

    Background Meckel–Gruber syndrome (MKS) is a genetically heterogeneous severe ciliopathy characterised by early lethality, occipital encephalocele, polydactyly, and polycystic kidney disease. Purpose To report genetic analysis results in two families in which all known MKS diseases genes have been excluded. Methods In two consanguineous families with classical MKS in which autozygome-guided sequencing of previously reported MKS genes was negative, we performed exome sequencing followed by autozygome filtration. Results We identified one novel splicing mutation in TMEM231, which led to complete degradation of the mutant transcript in one family, and a novel missense mutation in the other, both in the homozygous state. Conclusions TMEM231 represents a novel MKS locus. The very recent identification of TMEM231 mutations in Joubert syndrome supports the growing appreciation of the overlap in the molecular pathogenesis between these two ciliopathies. PMID:23349226

  3. Hungarian surveillance of germinal mutations. Lack of detectable increase in indicator conditions caused by germinal mutations following the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Czeizel, A. (National Inst. of Hygiene, Budapest (Hungary). Dept. of Human Genetics and Teratology)

    1989-07-01

    The Hungarian surveillance of germinal mutations is based on three indicator conditions seen in offspring, i.e., 15 sentinel anomalies, Down syndrome and component anomaly pairs of unidentified multiple congenital anomalies. It is an 'opportunistic program', because the necessary data are available from the Hungarian Congenital Malformation Registry. This system is described and the criteria of a good registry are summarized. The analysis of indicator conditions caused by germinal mutations did not reveal any measurable mutagenic effects in Hungary following the accident at the Chernobyl nuclear power plant. The pros and cons of germinal mutation surveillance are discussed. (orig.).

  4. Mutations that Cause Human Disease: A Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Beernink, P; Barsky, D; Pesavento, B

    2006-01-11

    International genome sequencing projects have produced billions of nucleotides (letters) of DNA sequence data, including the complete genome sequences of 74 organisms. These genome sequences have created many new scientific opportunities, including the ability to identify sequence variations among individuals within a species. These genetic differences, which are known as single nucleotide polymorphisms (SNPs), are particularly important in understanding the genetic basis for disease susceptibility. Since the report of the complete human genome sequence, over two million human SNPs have been identified, including a large-scale comparison of an entire chromosome from twenty individuals. Of the protein coding SNPs (cSNPs), approximately half leads to a single amino acid change in the encoded protein (non-synonymous coding SNPs). Most of these changes are functionally silent, while the remainder negatively impact the protein and sometimes cause human disease. To date, over 550 SNPs have been found to cause single locus (monogenic) diseases and many others have been associated with polygenic diseases. SNPs have been linked to specific human diseases, including late-onset Parkinson disease, autism, rheumatoid arthritis and cancer. The ability to predict accurately the effects of these SNPs on protein function would represent a major advance toward understanding these diseases. To date several attempts have been made toward predicting the effects of such mutations. The most successful of these is a computational approach called ''Sorting Intolerant From Tolerant'' (SIFT). This method uses sequence conservation among many similar proteins to predict which residues in a protein are functionally important. However, this method suffers from several limitations. First, a query sequence must have a sufficient number of relatives to infer sequence conservation. Second, this method does not make use of or provide any information on protein structure, which

  5. MAX mutations cause hereditary and sporadic pheochromocytoma and paraganglioma

    NARCIS (Netherlands)

    N. Burnichon (Nelly); A. Cascoń (Alberto); F. Schiavi (Francesca); N. Morales (NicolePaes); I. Comino-Méndez (Iñaki); N. Abermil (Nasséra); L. Inglada-Pérez (Lucía); A.A. de Cubas (Aguirre); L. Amar (Laurence); M. Barontini (Marta); S.B. de Quiroś (Sandra Bernaldo); J. Bertherat (Jerome); Y.-J. Bignon (Yves-Jean); M.J. Blok (Marinus); S. Bobisse (Sara); S. Borrego (Salud); M. Castellano (Maurizio); P. Chanson (Philippe); A. de Chiara; E.P. Corssmit (Eleonora); M. Giacchè (Mara); R.R. de Krijger (Ronald); T. Ercolino (Tonino); X. Girerd (Xavier); E.B. Gómez García (Encarna); Á. Gómez-Graña (Álvaro); I. Guilhem (Isabelle); F.J. Hes (Frederik); E. Honrado (Emiliano); E. Korpershoek (Esther); J.W. Lenders (Jacques); R. Letón (Rocío); A.R. Mensenkamp (Arjen); A. Merlo (Anna); L. Mori (Luigi); A. Murat (Arnaud); P. Pierre (Peggy); P.F. Plouin (Pierre-Franco̧is); T. Prodanov (Tamara); M. Quesada-Charneco (Miguel); N. Qin (Nan); E. Rapizzi (Elena); E. Raymond (Eric); N. Reisch (Nicole); G. Roncador (Giovanna); M. Ruiz-Ferrer (Macarena); F. Schillo (Frank); A.P.A. Stegmann (Sander); C. Suarez (Carlos); E. Taschin (Elisa); H.J.L.M. Timmers; C. Tops (Carli); M. Urioste (Miguel); F. Beuschlein (Felix); K. Pacak (Karel); M. Mannelli (Massimo); P.L. Dahia (Patricia); G. Opocher (Giuseppe); G. Eisenhofer (Graeme); A.P. Gimenez-Roqueplo; M. Robledo (Mercedes)

    2012-01-01

    textabstractPurpose: Pheochromocytomas (PCC) and paragangliomas (PGL) are genetically heterogeneous neural crest-derived neoplasms. Recently we identified germline mutations in a new tumor suppressor susceptibility gene, MAX (MYC-associated factor X), which predisposes carriers to PCC. How MAX

  6. Mutations in KCNT1 cause a spectrum of focal epilepsies

    DEFF Research Database (Denmark)

    Møller, Rikke Steensbjerre; Heron, Sarah E.; Larsen, Line H. G.

    2015-01-01

    Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associated w...

  7. Cantu syndrome is caused by mutations in ABCC9

    NARCIS (Netherlands)

    Bon, B.W. van; Gilissen, C.; Grange, D.K.; Hennekam, R.C.; Kayserili, H.; Engels, H.; Reutter, H.; Ostergaard, J.R.; Morava, E.; Tsiakas, K.; Isidor, B.; Merrer, M. le; Eser, M.; Wieskamp, N.; Vries, P. de; Steehouwer, M.; Veltman, J.A.; Robertson, S.P.; Brunner, H.G.; Vries, B.B. de; Hoischen, A.

    2012-01-01

    Cantu syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9

  8. Rabson Mendenhall Syndrome caused by a novel missense mutation.

    Science.gov (United States)

    Sinnarajah, Krishnapradeep; Dayasiri, M B K C; Dissanayake, N D W; Kudagammana, S T; Jayaweera, A H H M

    2016-01-01

    Rabson Mendenhall syndrome is a rare endocrine condition characterized by severe insulin resistance and hyperglycemia. It occurs due to mutations in the insulin receptor gene. Few mutations which are associated with Rabson Mendenhall syndrome have been identified and reported in the past. The management of this condition is extremely challenging and will need multi-disciplinary approach. An 11 year old boy presented with polyuria and polydipsia. He was noted to have coarse facies, severe acanthosis nigricans, hypertrichosis, retarded growth and developmental delay. Investigations revealed severe hyperglycemia which was poorly responsive to high doses of insulin. A diagnosis of Rabson Mendenhall syndrome was suspected based on his physical characteristics in the presence of insulin resistance. Genetic studies revealed a homozygous missense mutation in the Insulin receptor gene confirming the diagnosis of Rabson Mendenhall syndrome. This is a novel mutation which has not been reported previously. Rabson Mendenhall syndrome should be suspected in a patient with characteristic physical features, severe hyperglycemia and insulin resistance. The genetic studies will not only confirm the diagnosis but also will help in counselling. Wider collaboration is needed to identify definitive treatment options for managing this rare condition.

  9. Mutations in the NHEJ component XRCC4 cause primordial dwarfism

    NARCIS (Netherlands)

    J.E. Murray (Jennie E.); M. van der Burg (Mirjam); H. IJspeert (Hanna); P. Carroll (Paula); Q. Wu (Qian); T. Ochi (Takashi); A. Leitch (Andrea); E.S. Miller (Edward S.); B. Kysela (Boris); A. Jawad (Alireza); A. Bottani (Armand); F. Brancati (Fred); M. Cappa (Marco); V. Cormier-Daire (Valerie); C. Deshpande (Charu); E.A. Faqeih (Eissa A.); G.E. Graham (Gail E.); E. Ranza (Emmanuelle); T.L. Blundell (Tom L.); A.P. Jackson (Andrew); G.S. Stewart (Grant S.); L.S. Bicknell (Louise)

    2015-01-01

    textabstractNon-homologous end joining (NHEJ) is a key cellular process ensuring genome integrity. Mutations in several components of the NHEJ pathway have been identified, often associated with severe combined immunodeficiency (SCID), consistent with the requirement for NHEJ during V(D)J

  10. KIF7 mutations cause fetal hydrolethalus and acrocallosal syndromes

    NARCIS (Netherlands)

    A. Putoux; S. Thomas; K.L.M. Coene; E.E. Davis; Y. Alanay; G. Ogur; E. Uz; D. Buzas; C. Gomes; S. Patrier; C.L. Bennett; N. Elkhartoufi; M.-H. Saint Frison; L. Rigonnot; N. Joye; S. Pruvost; G.E. Utine; K. Boduroglu; P. Nitschke; L. Fertitta; C. Thauvin-Robinet; A. Munnich; V. Cormier-Daire; R. Hennekam; E. Colin; N.A. Akarsu; C. Bole-Feysot; N. Cagnard; A. Schmitt; N. Goudin; S. Lyonnet; F. Encha-Razavi; J.P. Siffroi; M. Winey; N. Katsanis; M. Gonzales; M. Vekemans; P.L. Beales; T. Attie-Bitach

    2011-01-01

    KIF7, the human ortholog of Drosophila Costal2, is a key component of the Hedgehog signaling pathway. Here we report mutations in KIF7 in individuals with hydrolethalus and acrocallosal syndromes, two multiple malformation disorders with overlapping features that include polydactyly, brain abnormali

  11. Mutations in KCNT1 cause a spectrum of focal epilepsies

    NARCIS (Netherlands)

    Møller, Rikke S.; Heron, Sarah E.; Larsen, Line H G; Lim, Chiao Xin; Ricos, Michael G.; Bayly, Marta A.; Van Kempen, Marjan J A; Klinkenberg, Sylvia; Andrews, Ian; Kelley, Kent; Ronen, Gabriel M.; Callen, David; McMahon, Jacinta M.; Yendle, Simone C.; Carvill, Gemma L.; Mefford, Heather C.; Nabbout, Rima; Poduri, Annapurna; Striano, Pasquale; Baglietto, Maria G.; Zara, Federico; Smith, Nicholas J.; Pridmore, Clair; Gardella, Elena; Nikanorova, Marina; Dahl, Hans Atli; Gellert, Pia; Scheffer, Ingrid E.; Gunning, Boudewijn; Kragh-Olsen, Bente; Dibbens, Leanne M.

    2015-01-01

    Summary Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associa

  12. Mosaic Activating Mutations in FGFR1 Cause Encephalocraniocutaneous Lipomatosis

    Science.gov (United States)

    Bennett, James T.; Tan, Tiong Yang; Alcantara, Diana; Tétrault, Martine; Timms, Andrew E.; Jensen, Dana; Collins, Sarah; Nowaczyk, Malgorzata J.M.; Lindhurst, Marjorie J.; Christensen, Katherine M.; Braddock, Stephen R.; Brandling-Bennett, Heather; Hennekam, Raoul C.M.; Chung, Brian; Lehman, Anna; Su, John; Ng, SuYuen; Amor, David J.; Majewski, Jacek; Biesecker, Les G.; Boycott, Kym M.; Dobyns, William B.; O’Driscoll, Mark; Moog, Ute; McDonell, Laura M.

    2016-01-01

    Encephalocraniocutaneous lipomatosis (ECCL) is a sporadic condition characterized by ocular, cutaneous, and central nervous system anomalies. Key clinical features include a well-demarcated hairless fatty nevus on the scalp, benign ocular tumors, and central nervous system lipomas. Seizures, spasticity, and intellectual disability can be present, although affected individuals without seizures and with normal intellect have also been reported. Given the patchy and asymmetric nature of the malformations, ECCL has been hypothesized to be due to a post-zygotic, mosaic mutation. Despite phenotypic overlap with several other disorders associated with mutations in the RAS-MAPK and PI3K-AKT pathways, the molecular etiology of ECCL remains unknown. Using exome sequencing of DNA from multiple affected tissues from five unrelated individuals with ECCL, we identified two mosaic mutations, c.1638C>A (p.Asn546Lys) and c.1966A>G (p.Lys656Glu) within the tyrosine kinase domain of FGFR1, in two affected individuals each. These two residues are the most commonly mutated residues in FGFR1 in human cancers and are associated primarily with CNS tumors. Targeted resequencing of FGFR1 in multiple tissues from an independent cohort of individuals with ECCL identified one additional individual with a c.1638C>A (p.Asn546Lys) mutation in FGFR1. Functional studies of ECCL fibroblast cell lines show increased levels of phosphorylated FGFRs and phosphorylated FRS2, a direct substrate of FGFR1, as well as constitutive activation of RAS-MAPK signaling. In addition to identifying the molecular etiology of ECCL, our results support the emerging overlap between mosaic developmental disorders and tumorigenesis. PMID:26942290

  13. Sensorineural hearing loss caused by MYH14 gene mutation. A case report

    Directory of Open Access Journals (Sweden)

    Pedro CARNEIRO-SOUSA

    2016-11-01

    Full Text Available Introduction and objective: Hereditary causes are responsible for half of cases of sensorineural hearing loss in young people. MYH14 mutation is autosomal dominant. Description: A 33 years-old patient with moderate-to-severe sensorineural hearing loss. Genetic study revealed MYH14 mutation. Discussion: This is a case of post-lingual sensorineural deafness, compatible with autosomal dominant inheritance. MYH14 mutation seems to increase susceptibility to acoustic trauma, which may justify the late onset of hearing loss. Conclusions: MYH14 mutation is, probably, a cause for hearing loss. Genetic study has, therefore, a growing importance.

  14. Clinical study of DMD gene point mutation causing Becker muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Ji-qing CAO

    2015-07-01

    Full Text Available Background  DMD gene point mutation, mainly nonsense mutation, always cause the most severe Duchenne muscular dystrophy (DMD. However, we also observed some cases of Becker muscular dystrophy (BMD carrying DMD point mutation. This paper aims to explore the mechanism of DMD point mutation causing BMD, in order to enhance the understanding of mutation types of BMD.  Methods  Sequence analysis was performed in 11 cases of BMD confirmed by typical clinical manifestations and muscle biopsy. The exon of DMD gene was detected non-deletion or duplication by multiplex ligation-dependent probe amplification (MLPA.  Results  Eleven patients carried 10 mutation types without mutational hotspot. Six patients carried nonsense mutations [c.5002G>T, p.(Glu1668X; c.1615C > T, p.(Arg539X; c.7105G > T, p.(Glu2369X; c.5287C > T, p.(Arg1763X; c.9284T > G, p.(Leu3095X]. One patient carried missense mutation [c.5234G > A, p.(Arg1745His]. Two patients carried frameshift mutations (c.10231dupT, c.10491delC. Two patients carried splicing site mutations (c.4518 + 3A > T, c.649 + 2T > C.  Conclusions  DMD gene point mutation may result in BMD with mild clinical symptoms. When clinical manifestations suggest the possibility of BMD and MLPA reveals non?deletion or duplication mutation of DMD gene, BMD should be considered. Study on the mechanism of DMD point mutation causing BMD is very important for gene therapy of DMD. DOI: 10.3969/j.issn.1672-6731.2015.06.005

  15. Two Novel De Novo GARS Mutations Cause Early-Onset Axonal Charcot-Marie-Tooth Disease.

    Directory of Open Access Journals (Sweden)

    Yi-Chu Liao

    Full Text Available Mutations in the GARS gene have been identified in a small number of patients with Charcot-Marie-Tooth disease (CMT type 2D or distal spinal muscular atrophy type V, for whom disease onset typically occurs during adolescence or young adulthood, initially manifesting as weakness and atrophy of the hand muscles. The role of GARS mutations in patients with inherited neuropathies in Taiwan remains elusive.Mutational analyses of the coding regions of GARS were performed using targeted sequencing of 54 patients with molecularly unassigned axonal CMT, who were selected from 340 unrelated CMT patients. Two heterozygous mutations in GARS, p.Asp146Tyr and p.Met238Arg, were identified; one in each patient. Both are novel de novo mutations. The p.Asp146Tyr mutation is associated with a severe infantile-onset neuropathy and the p.Met238Arg mutation results in childhood-onset disability.GARS mutations are an uncommon cause of CMT in Taiwan. The p.Asp146Tyr and p.Met238Arg mutations are associated with early-onset axonal CMT. These findings broaden the mutational spectrum of GARS and also highlight the importance of considering GARS mutations as a disease cause in patients with early-onset neuropathies.

  16. Two Novel De Novo GARS Mutations Cause Early-Onset Axonal Charcot-Marie-Tooth Disease.

    Science.gov (United States)

    Liao, Yi-Chu; Liu, Yo-Tsen; Tsai, Pei-Chien; Chang, Chia-Ching; Huang, Yen-Hua; Soong, Bing-Wen; Lee, Yi-Chung

    2015-01-01

    Mutations in the GARS gene have been identified in a small number of patients with Charcot-Marie-Tooth disease (CMT) type 2D or distal spinal muscular atrophy type V, for whom disease onset typically occurs during adolescence or young adulthood, initially manifesting as weakness and atrophy of the hand muscles. The role of GARS mutations in patients with inherited neuropathies in Taiwan remains elusive. Mutational analyses of the coding regions of GARS were performed using targeted sequencing of 54 patients with molecularly unassigned axonal CMT, who were selected from 340 unrelated CMT patients. Two heterozygous mutations in GARS, p.Asp146Tyr and p.Met238Arg, were identified; one in each patient. Both are novel de novo mutations. The p.Asp146Tyr mutation is associated with a severe infantile-onset neuropathy and the p.Met238Arg mutation results in childhood-onset disability. GARS mutations are an uncommon cause of CMT in Taiwan. The p.Asp146Tyr and p.Met238Arg mutations are associated with early-onset axonal CMT. These findings broaden the mutational spectrum of GARS and also highlight the importance of considering GARS mutations as a disease cause in patients with early-onset neuropathies.

  17. ALDH1A3 mutations cause recessive anophthalmia and microphthalmia.

    Science.gov (United States)

    Fares-Taie, Lucas; Gerber, Sylvie; Chassaing, Nicolas; Clayton-Smith, Jill; Hanein, Sylvain; Silva, Eduardo; Serey, Margaux; Serre, Valérie; Gérard, Xavier; Baumann, Clarisse; Plessis, Ghislaine; Demeer, Bénédicte; Brétillon, Lionel; Bole, Christine; Nitschke, Patrick; Munnich, Arnold; Lyonnet, Stanislas; Calvas, Patrick; Kaplan, Josseline; Ragge, Nicola; Rozet, Jean-Michel

    2013-02-01

    Anophthalmia and microphthalmia (A/M) are early-eye-development anomalies resulting in absent or small ocular globes, respectively. A/M anomalies occur in syndromic or nonsyndromic forms. They are genetically heterogeneous, some mutations in some genes being responsible for both anophthalmia and microphthalmia. Using a combination of homozygosity mapping, exome sequencing, and Sanger sequencing, we identified homozygosity for one splice-site and two missense mutations in the gene encoding the A3 isoform of the aldehyde dehydrogenase 1 (ALDH1A3) in three consanguineous families segregating A/M with occasional orbital cystic, neurological, and cardiac anomalies. ALDH1A3 is a key enzyme in the formation of a retinoic acid gradient along the dorso-ventral axis during early eye development. Transitory expression of mutant ALDH1A3 open reading frames showed that both missense mutations reduce the accumulation of the enzyme, potentially leading to altered retinoic acid synthesis. Although the role of retinoic acid signaling in eye development is well established, our findings provide genetic evidence of a direct link between retinoic-acid-synthesis dysfunction and early-eye-development anomalies in humans.

  18. De novo mutations in synaptic transmission genes including DNM1 cause epileptic encephalopathies

    DEFF Research Database (Denmark)

    2014-01-01

    analyzed exome-sequencing data of 356 trios with the "classical" epileptic encephalopathies, infantile spasms and Lennox Gastaut syndrome, including 264 trios previously analyzed by the Epi4K/EPGP consortium. In this expanded cohort, we find 429 de novo mutations, including de novo mutations in DNM1...... = 8.2 × 10(-4)), supporting a prominent role for de novo mutations in epileptic encephalopathies. We bring statistical evidence that mutations in DNM1 cause epileptic encephalopathy, find suggestive evidence for a role of three additional genes, and show that at least 12% of analyzed individuals have...... an identifiable causal de novo mutation. Strikingly, 75% of mutations in these probands are predicted to disrupt a protein involved in regulating synaptic transmission, and there is a significant enrichment of de novo mutations in genes in this pathway in the entire cohort as well. These findings emphasize...

  19. Structural modeling of a novel CAPN5 mutation that causes uveitis and neovascular retinal detachment.

    Directory of Open Access Journals (Sweden)

    Alexander G Bassuk

    Full Text Available CAPN5 mutations have been linked to autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV, a blinding autoimmune eye disease. Here, we link a new CAPN5 mutation to ADNIV and model the three-dimensional structure of the resulting mutant protein. In our study, a kindred with inflammatory vitreoretinopathy was evaluated by clinical eye examinations, DNA sequencing, and protein structural modeling to investigate the disease-causing mutation. Two daughters of an affected mother demonstrated symptoms of stage III ADNIV, with posterior uveitis, cystoid macular edema, intraocular fibrosis, retinal neovascularization, retinal degeneration, and cataract. The women also harbored a novel guanine to thymine (c.750G>T, p.Lys250Asn missense mutation in exon 6 of CAPN5, a gene that encodes a calcium-activated cysteine protease, calpain-5. Modeling based on the structures of all known calpains revealed the mutation falls within a calcium-sensitive flexible gating loop that controls access to the catalytic groove. Three-dimensional modeling placed the new mutation in a region adjacent to two previously identified disease-causing mutations, all three of which likely disrupt hydrogen bonding within the gating loop, yielding a CAPN5 with altered enzymatic activity. This is the third case of a CAPN5 mutation leading to inherited uveitis and neovascular vitreoretinopathy, suggesting patients with ADNIV features should be tested for CAPN5 mutations. Structural modeling of novel variants can be used to support mechanistic consequences of the disease-causing variants.

  20. Nocturnal frontal lobe epilepsy caused by a mutation in the GATOR1 complex gene NPRL3.

    Science.gov (United States)

    Korenke, Georg-Christoph; Eggert, Marlene; Thiele, Holger; Nürnberg, Peter; Sander, Thomas; Steinlein, Ortrud K

    2016-03-01

    Mutations in NPRL3, one of three genes that encode proteins of the mTORC1-regulating GATOR1 complex, have recently been reported to cause cortical dysplasia with focal epilepsy. We have now analyzed a multiplex epilepsy family by whole exome sequencing and identified a frameshift mutation (NM_001077350.2; c.1522delG; p.E508Rfs*46) within exon 13 of NPRL3. This truncating mutation causes an epilepsy phenotype characterized by early childhood onset of mainly nocturnal frontal lobe epilepsy. The penetrance in our family was low (three affected out of six mutation carriers), compared to families with either ion channel- or DEPDC5-associated familial nocturnal frontal lobe epilepsy. The absence of apparent structural brain abnormalities suggests that mutations in NPRL3 are not necessarily associated with focal cortical dysplasia but might be able to cause epilepsy by different, yet unknown pathomechanisms.

  1. Disease causing mutations of troponin alter regulated actin state distributions.

    Science.gov (United States)

    Chalovich, Joseph M

    2012-12-01

    Striated muscle contraction is regulated primarily through the action of tropomyosin and troponin that are bound to actin. Activation requires Ca(2+) binding to troponin and/or binding of high affinity myosin complexes to actin. Mutations within components of the regulatory complex may lead to familial cardiomyopathies and myopathies. In several cases examined, either physiological or pathological changes in troponin alter the distribution among states of actin-tropomyosin-troponin that differ in their abilities to stimulate myosin ATPase activity. These observations open possibilities for managing disorders of the troponin complex. Furthermore, analyses of mutant forms of troponin give insights into the regulation of striated muscle contraction.

  2. Dynamin 2 mutations cause sporadic centronuclear myopathy with neonatal onset.

    Science.gov (United States)

    Bitoun, Marc; Bevilacqua, Jorge A; Prudhon, Bernard; Maugenre, Svetlana; Taratuto, Ana Lia; Monges, Soledad; Lubieniecki, Fabiana; Cances, Claude; Uro-Coste, Emmanuelle; Mayer, Michèle; Fardeau, Michel; Romero, Norma B; Guicheney, Pascale

    2007-12-01

    We report four heterozygous dynamin 2 (DNM2) mutations in five centronuclear myopathy patients aged 1 to 15 years. They all presented with neonatal hypotonia with weak suckling. Thereafter, their phenotype progressively improved. All patients demonstrated muscle weakness prominent in the lower limbs, and most of them also presented with facial weakness, open mouth, arched palate, ptosis, and ophthalmoparesis. Electrophysiology showed only myopathic changes, and muscle biopsies showed central nuclei and type 1 fiber hypotrophy and predominance. Our results expand the phenotypic spectrum of dynamin 2-related centronuclear myopathy from the classic mild form to the more severe neonatal phenotype.

  3. A Novel Myosin Essential Light Chain Mutation Causes Hypertrophic Cardiomyopathy with Late Onset and Low Expressivity

    Directory of Open Access Journals (Sweden)

    Paal Skytt Andersen

    2012-01-01

    Full Text Available Hypertrophic cardiomyopathy (HCM is caused by mutations in genes encoding sarcomere proteins. Mutations in MYL3, encoding the essential light chain of myosin, are rare and have been associated with sudden death. Both recessive and dominant patterns of inheritance have been suggested. We studied a large family with a 38-year-old asymptomatic HCM-affected male referred because of a murmur. The patient had HCM with left ventricular hypertrophy (max WT 21 mm, a resting left ventricular outflow gradient of 36 mm Hg, and left atrial dilation (54 mm. Genotyping revealed heterozygosity for a novel missense mutation, p.V79I, in MYL3. The mutation was not found in 300 controls, and the patient had no mutations in 10 sarcomere genes. Cascade screening revealed a further nine heterozygote mutation carriers, three of whom had ECG and/or echocardiographic abnormalities but did not fulfil diagnostic criteria for HCM. The penetrance, if we consider this borderline HCM the phenotype of the p.V79I mutation, was 40%, but the mean age of the nonpenetrant mutation carriers is 15, while the mean age of the penetrant mutation carriers is 47. The mutation affects a conserved valine replacing it with a larger isoleucine residue in the region of contact between the light chain and the myosin lever arm. In conclusion, MYL3 mutations can present with low expressivity and late onset.

  4. Dominant beta-catenin mutations cause intellectual disability with recognizable syndromic features

    NARCIS (Netherlands)

    Tucci, V.; Kleefstra, T.; Hardy, A.; Heise, I.; Maggi, S.; Willemsen, M.H.; Hilton, H.; Esapa, C.; Simon, M.; Buenavista, M.T.; McGuffin, L.J.; Vizor, L.; Dodero, L.; Tsaftaris, S.; Romero, R.; Nillesen, W.N.; Vissers, L.E.L.M.; Kempers, M.J.E.; Silfhout, A.T. van; Iqbal, Z.; Orlando, M.; Maccione, A.; Lassi, G.; Farisello, P.; Contestabile, A.; Tinarelli, F.; Nieus, T.; Raimondi, A.; Greco, B.; Cantatore, D.; Gasparini, L.; Berdondini, L.; Bifone, A.; Gozzi, A.; Wells, S.; Nolan, P.M.

    2014-01-01

    The recent identification of multiple dominant mutations in the gene encoding beta-catenin in both humans and mice has enabled exploration of the molecular and cellular basis of beta-catenin function in cognitive impairment. In humans, beta-catenin mutations that cause a spectrum of neurodevelopment

  5. Mutations in OTOGL, encoding the inner ear protein otogelin-like, cause moderate sensorineural hearing loss

    NARCIS (Netherlands)

    Yariz, K.O.; Duman, D.; Seco, C.Z.; Dallman, J.; Huang, M.; Peters, T.A.; Sirmaci, A.; Lu, N.; Schraders, M.; Skromne, I.; Oostrik, J.; Diaz-Horta, O.; Young, J.I.; Tokgoz-Yilmaz, S.; Konukseven, O.; Shahin, H.; Hetterschijt, L.; Kanaan, M.; Oonk, A.M.M.; Edwards, Y.J.; Li, H.; Atalay, S.; Blanton, S.; Desmidt, A.A.; Liu, X.Z.; Pennings, R.J.E.; Lu, Z.; Chen, Z.Y.; Kremer, J.M.J.; Tekin, M.

    2012-01-01

    Hereditary hearing loss is characterized by a high degree of genetic heterogeneity. Here we present OTOGL mutations, a homozygous one base pair deletion (c.1430 delT) causing a frameshift (p.Val477Glufs( *)25) in a large consanguineous family and two compound heterozygous mutations, c.547C>T (p.Arg1

  6. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    Thiadens, A.A.H.J.; Soerjoesing, G.G.; Florijn, R.J.; Tjiam, A.G.; Hollander, A.I. den; Born, L.I. van den; Riemslag, F.C.; Bergen, A.A.B.; Klaver, C.C.

    2011-01-01

    BACKGROUND: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. METHODS: We investigated an X-linked cone dystrophy family (1) with 25

  7. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    A.A.H.J. Thiadens (Alberta); G.G. Soerjoesing (Gyan); R.J. Florijn; A.G. Tjiam; A.I. Hollander (Anneke); L.I. van den Born (Ingeborgh); F.C.C. Riemslag (Frans); A.A.B. Bergen (Arthur); C.C.W. Klaver (Caroline)

    2011-01-01

    textabstractBackground: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. Methods: We investigated an X-linked cone dystrophy family (1)

  8. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes

    DEFF Research Database (Denmark)

    Schubert, J.; Siekierska, A.; Langlois, M.

    2014-01-01

    Febrile seizures affect 2-4% of all children(1) and have a strong genetic component(2). Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2)(3-5) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encodi...

  9. Indian hedgehog mutations causing brachydactyly type A1 impair Hedgehog signal transduction at multiple levels

    Institute of Scientific and Technical Information of China (English)

    Gang Ma; Jiang Yu; Yue Xiao; Danny Chan; Bo Gao; Jianxin Hu; Yongxing He

    2011-01-01

    Brachydactyly type A1 (BDA1),the first recorded Mendelian autosomal dominant disorder in humans,is characterized by a shortening or absence of the middle phalanges.Heterozygous missense mutations in the Indian Hedgehog (IHH) gene have been identified as a cause of BDA1; however,the biochemical consequences of these mutations are unclear.In this paper,we analyzed three BDA1 mutations (E95K,D100E,and E131K)in the N-terminal fragment of Indian Hedgehog (IhhN).Structural analysis showed that the E95K mutation changes a negatively charged area to a positively charged area in a calcium-binding groove,and that the D100E mutation changes the local tertiary structure.Furthermore,we showed that the E95K and D100E mutations led to a temperature-sensitive and calcium-dependent instability of lhhN,which might contribute to an enhanced intracellular degradation of the mutant proteins via the lysosome.Notably,all three mutations affected Hh binding to the receptor Patched1 (PTC1),reducing its capacity to induce cellular differentiation.We propose that these are common features of the mutations that cause BDA1,affecting the Hh tertiary structure,intracellular fate,binding to the receptor/partners,and binding to extracellular components.The combination of these features alters signaling capacity and range,but the impact is likely to be variable and mutation-dependent.The potential variation in the signaling range is characterized by an enhanced interaction with heparan sulfate for IHH with the E95K mutation,but not the E131K mutation.Taken together,our results suggest that these IHH mutations affect Hh signaling at multiple levels,causing abnormal bone development and abnormal digit formation.

  10. m.3635G>A mutation as a cause of Leber hereditary optic neuropathy.

    Science.gov (United States)

    Kodroń, Agata; Krawczyński, Maciej R; Tońska, Katarzyna; Bartnik, Ewa

    2014-07-01

    Over 90% of Leber's hereditary optic neuropathy (LHON) is caused by one of three mtDNA mutations (m.11778A>G, m.3460G>A, m.14484T>C). The remaining cases are due to rare mutations in different genes encoding subunits of the respiratory chain. The proband is a 17-year-old male with symptoms of optic nerve atrophy. No common LHON mutations were found, but detailed sequencing identified a rare, homoplasmic mutation m.3635G>A in the ND1 gene.

  11. Quantitative and sensitive detection of GNAS mutations causing mccune-albright syndrome with next generation sequencing.

    Science.gov (United States)

    Narumi, Satoshi; Matsuo, Kumihiro; Ishii, Tomohiro; Tanahashi, Yusuke; Hasegawa, Tomonobu

    2013-01-01

    Somatic activating GNAS mutations cause McCune-Albright syndrome (MAS). Owing to low mutation abundance, mutant-specific enrichment procedures, such as the peptide nucleic acid (PNA) method, are required to detect mutations in peripheral blood. Next generation sequencing (NGS) can analyze millions of PCR amplicons independently, thus it is expected to detect low-abundance GNAS mutations quantitatively. In the present study, we aimed to develop an NGS-based method to detect low-abundance somatic GNAS mutations. PCR amplicons encompassing exons 8 and 9 of GNAS, in which most activating mutations occur, were sequenced on the MiSeq instrument. As expected, our NGS-based method could sequence the GNAS locus with very high read depth (approximately 100,000) and low error rate. A serial dilution study with use of cloned mutant and wildtype DNA samples showed a linear correlation between dilution and measured mutation abundance, indicating the reliability of quantification of the mutation. Using the serially diluted samples, the detection limits of three mutation detection methods (the PNA method, NGS, and combinatory use of PNA and NGS [PNA-NGS]) were determined. The lowest detectable mutation abundance was 1% for the PNA method, 0.03% for NGS and 0.01% for PNA-NGS. Finally, we analyzed 16 MAS patient-derived leukocytic DNA samples with the three methods, and compared the mutation detection rate of them. Mutation detection rate of the PNA method, NGS and PNA-NGS in 16 patient-derived peripheral blood samples were 56%, 63% and 75%, respectively. In conclusion, NGS can detect somatic activating GNAS mutations quantitatively and sensitively from peripheral blood samples. At present, the PNA-NGS method is likely the most sensitive method to detect low-abundance GNAS mutation.

  12. Quantitative and sensitive detection of GNAS mutations causing mccune-albright syndrome with next generation sequencing.

    Directory of Open Access Journals (Sweden)

    Satoshi Narumi

    Full Text Available Somatic activating GNAS mutations cause McCune-Albright syndrome (MAS. Owing to low mutation abundance, mutant-specific enrichment procedures, such as the peptide nucleic acid (PNA method, are required to detect mutations in peripheral blood. Next generation sequencing (NGS can analyze millions of PCR amplicons independently, thus it is expected to detect low-abundance GNAS mutations quantitatively. In the present study, we aimed to develop an NGS-based method to detect low-abundance somatic GNAS mutations. PCR amplicons encompassing exons 8 and 9 of GNAS, in which most activating mutations occur, were sequenced on the MiSeq instrument. As expected, our NGS-based method could sequence the GNAS locus with very high read depth (approximately 100,000 and low error rate. A serial dilution study with use of cloned mutant and wildtype DNA samples showed a linear correlation between dilution and measured mutation abundance, indicating the reliability of quantification of the mutation. Using the serially diluted samples, the detection limits of three mutation detection methods (the PNA method, NGS, and combinatory use of PNA and NGS [PNA-NGS] were determined. The lowest detectable mutation abundance was 1% for the PNA method, 0.03% for NGS and 0.01% for PNA-NGS. Finally, we analyzed 16 MAS patient-derived leukocytic DNA samples with the three methods, and compared the mutation detection rate of them. Mutation detection rate of the PNA method, NGS and PNA-NGS in 16 patient-derived peripheral blood samples were 56%, 63% and 75%, respectively. In conclusion, NGS can detect somatic activating GNAS mutations quantitatively and sensitively from peripheral blood samples. At present, the PNA-NGS method is likely the most sensitive method to detect low-abundance GNAS mutation.

  13. Mutations in the promoter region of the aldolase B gene that cause hereditary fructose intolerance.

    Science.gov (United States)

    Coffee, Erin M; Tolan, Dean R

    2010-12-01

    Hereditary fructose intolerance (HFI) is a potentially fatal inherited metabolic disease caused by a deficiency of aldolase B activity in the liver and kidney. Over 40 disease-causing mutations are known in the protein-coding region of ALDOB. Mutations upstream of the protein-coding portion of ALDOB are reported here for the first time. DNA sequence analysis of 61 HFI patients revealed single base mutations in the promoter, intronic enhancer, and the first exon, which is entirely untranslated. One mutation, g.-132G>A, is located within the promoter at an evolutionarily conserved nucleotide within a transcription factor-binding site. A second mutation, IVS1+1G>C, is at the donor splice site of the first exon. In vitro electrophoretic mobility shift assays show a decrease in nuclear extract-protein binding at the g.-132G>A mutant site. The promoter mutation results in decreased transcription using luciferase reporter plasmids. Analysis of cDNA from cells transfected with plasmids harboring the IVS1+1G>C mutation results in aberrant splicing leading to complete retention of the first intron (~5 kb). The IVS1+1G>C splicing mutation results in loss of luciferase activity from a reporter plasmid. These novel mutations in ALDOB represent 2% of alleles in American HFI patients, with IVS1+1G>C representing a significantly higher allele frequency (6%) among HFI patients of Hispanic and African-American ethnicity.

  14. New mutations in MAPT gene causing frontotemporal lobar degeneration: biochemical and structural characterization.

    Science.gov (United States)

    Rossi, Giacomina; Bastone, Antonio; Piccoli, Elena; Mazzoleni, Giulia; Morbin, Michela; Uggetti, Andrea; Giaccone, Giorgio; Sperber, Sarah; Beeg, Marten; Salmona, Mario; Tagliavini, Fabrizio

    2012-04-01

    Frontotemporal lobar degeneration (FTLD) can be sporadic or familial. The genes encoding the microtubule-associated protein tau (MAPT) and progranulin (GRN) are the most relevant genes so far known causing the hereditary forms. Following genetic screening of patients affected by FTLD, we identified 2 new MAPT mutations, P364S and G366R, the former in a sporadic case. In the study we report the clinical and genetic features of the patients carrying these mutations, and the functional effects of the mutations, analyzed in vitro in order to investigate their pathogenic character. Both mutations resulted in reduced ability of tau to promote microtubule polymerization; the P364S protein variant also showed a high propensity to aggregate into filaments. These results suggest a high probability that these mutations are pathogenic. Our findings highlight the importance of genetic analysis also in sporadic forms of FTLD, and the role of in vitro studies to evaluate the pathologic features of new mutations.

  15. De novo mutations in ATP1A3 cause alternating hemiplegia of childhood

    Science.gov (United States)

    Heinzen, Erin L.; Swoboda, Kathryn J.; Hitomi, Yuki; Gurrieri, Fiorella; Nicole, Sophie; de Vries, Boukje; Tiziano, F. Danilo; Fontaine, Bertrand; Walley, Nicole M.; Heavin, Sinéad; Panagiotakaki, Eleni; Fiori, Stefania; Abiusi, Emanuela; Di Pietro, Lorena; Sweney, Matthew T.; Newcomb, Tara M.; Viollet, Louis; Huff, Chad; Jorde, Lynn B.; Reyna, Sandra P.; Murphy, Kelley J.; Shianna, Kevin V.; Gumbs, Curtis E.; Little, Latasha; Silver, Kenneth; Ptác̆ek, Louis J.; Haan, Joost; Ferrari, Michel D.; Bye, Ann M.; Herkes, Geoffrey K.; Whitelaw, Charlotte M.; Webb, David; Lynch, Bryan J.; Uldall, Peter; King, Mary D.; Scheffer, Ingrid E.; Neri, Giovanni; Arzimanoglou, Alexis; van den Maagdenberg, Arn M.J.M.; Sisodiya, Sanjay M.; Mikati, Mohamad A.; Goldstein, David B.; Nicole, Sophie; Gurrieri, Fiorella; Neri, Giovanni; de Vries, Boukje; Koelewijn, Stephany; Kamphorst, Jessica; Geilenkirchen, Marije; Pelzer, Nadine; Laan, Laura; Haan, Joost; Ferrari, Michel; van den Maagdenberg, Arn; Zucca, Claudio; Bassi, Maria Teresa; Franchini, Filippo; Vavassori, Rosaria; Giannotta, Melania; Gobbi, Giuseppe; Granata, Tiziana; Nardocci, Nardo; De Grandis, Elisa; Veneselli, Edvige; Stagnaro, Michela; Gurrieri, Fiorella; Neri, Giovanni; Vigevano, Federico; Panagiotakaki, Eleni; Oechsler, Claudia; Arzimanoglou, Alexis; Nicole, Sophie; Giannotta, Melania; Gobbi, Giuseppe; Ninan, Miriam; Neville, Brian; Ebinger, Friedrich; Fons, Carmen; Campistol, Jaume; Kemlink, David; Nevsimalova, Sona; Laan, Laura; Peeters-Scholte, Cacha; van den Maagdenberg, Arn; Casaer, Paul; Casari, Giorgio; Sange, Guenter; Spiel, Georg; Boneschi, Filippo Martinelli; Zucca, Claudio; Bassi, Maria Teresa; Schyns, Tsveta; Crawley, Francis; Poncelin, Dominique; Vavassori, Rosaria

    2012-01-01

    Alternating hemiplegia of childhood (AHC) is a rare, severe neurodevelopmental syndrome characterized by recurrent hemiplegic episodes and distinct neurologic manifestations. AHC is usually a sporadic disorder with unknown etiology. Using exome sequencing of seven patients with AHC, and their unaffected parents, we identified de novo nonsynonymous mutations in ATP1A3 in all seven AHC patients. Subsequent sequence analysis of ATP1A3 in 98 additional patients revealed that 78% of AHC cases have a likely causal ATP1A3 mutation, including one inherited mutation in a familial case of AHC. Remarkably, six ATP1A3 mutations explain the majority of patients, including one observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset-dystonia-parkinsonism, AHC-causing mutations revealed consistent reductions in ATPase activity without effects on protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC, and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in this gene. PMID:22842232

  16. Activating germline mutations in STAT3 cause early-onset multi-organ autoimmune disease.

    Science.gov (United States)

    Flanagan, Sarah E; Haapaniemi, Emma; Russell, Mark A; Caswell, Richard; Lango Allen, Hana; De Franco, Elisa; McDonald, Timothy J; Rajala, Hanna; Ramelius, Anita; Barton, John; Heiskanen, Kaarina; Heiskanen-Kosma, Tarja; Kajosaari, Merja; Murphy, Nuala P; Milenkovic, Tatjana; Seppänen, Mikko; Lernmark, Åke; Mustjoki, Satu; Otonkoski, Timo; Kere, Juha; Morgan, Noel G; Ellard, Sian; Hattersley, Andrew T

    2014-08-01

    Monogenic causes of autoimmunity provide key insights into the complex regulation of the immune system. We report a new monogenic cause of autoimmunity resulting from de novo germline activating STAT3 mutations in five individuals with a spectrum of early-onset autoimmune disease, including type 1 diabetes. These findings emphasize the critical role of STAT3 in autoimmune disease and contrast with the germline inactivating STAT3 mutations that result in hyper IgE syndrome.

  17. [Infantile hypophosphatasia caused by a novel compound heterozygous mutation: a case report and pedigree analysis].

    Science.gov (United States)

    Li, Deng-Feng; Lan, Dan; Zhong, Jing-Zi; Dewan, Roma Kajal; Xie, Yan-Shu; Yang, Ying

    2017-05-01

    This article reported the clinical features of one child with infantile hypophosphatasia (HPP) and his pedigree information. The proband was a 5-month-old boy with multiple skeletal dysplasia (koilosternia, bending deformity of both radii, and knock-knee deformity of both knees), feeding difficulty, reduction in body weight, developmental delay, recurrent pneumonia and respiratory failure, and a significant reduction in blood alkaline phosphatase. Among his parents, sister, uncle, and aunt (other family members did not cooperate with us in the examination), his parents and aunt had a slight reduction in alkaline phosphatase and his aunt had scoliosis; there were no other clinical phenotypes or abnormal laboratory testing results. His ALPL gene mutation came from c.228delG mutation in his mother and c.407G>A compound heterozygous mutation in his father. His aunt carried c.228delG mutation. The c.407G>A mutation had been reported as the pathogenic mutation of HPP, and c.228delG mutation was a novel pathogenic mutation. Hypophosphatasia is caused by ALPL gene mutation, and ALPL gene detection is an effective diagnostic method. This study expands the mutation spectrum of ALPL gene and provides a theoretical basis for genetic diagnosis of this disease.

  18. Splicing site mutations in dentin sialophosphoprotein causing dentinogenesis imperfecta type II.

    Science.gov (United States)

    Holappa, Heidi; Nieminen, Pekka; Tolva, Liisa; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu

    2006-10-01

    Dentinogenesis imperfecta (DGI) type II (OMIM # 125490) is an inherited disorder affecting dentin. Defective dentin formation results in discolored teeth that are prone to attrition and fracture. To date, several mutations have been described in the dentin sialophosphoprotein (DSPP) gene, causing DGI types II and III and dentin dysplasia type II. DSPP encodes two proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Here, we describe a mutational analysis of DSPP in seven Finnish families with DGI type II. We report two mutations and five single nucleotide polymorphisms. In one family we found a mutation that has been described earlier in families with different ethnicity, while in six families we found a novel g.1194C>A (IVS2-3) transversion. Bioinformatic analysis of known DSPP mutations suggests that DGI type II is usually caused by aberration of normal splicing.

  19. Mutations in the SPG7 gene cause chronic progressive external ophthalmoplegia through disordered mitochondrial DNA maintenance.

    Science.gov (United States)

    Pfeffer, Gerald; Gorman, Gráinne S; Griffin, Helen; Kurzawa-Akanbi, Marzena; Blakely, Emma L; Wilson, Ian; Sitarz, Kamil; Moore, David; Murphy, Julie L; Alston, Charlotte L; Pyle, Angela; Coxhead, Jon; Payne, Brendan; Gorrie, George H; Longman, Cheryl; Hadjivassiliou, Marios; McConville, John; Dick, David; Imam, Ibrahim; Hilton, David; Norwood, Fiona; Baker, Mark R; Jaiser, Stephan R; Yu-Wai-Man, Patrick; Farrell, Michael; McCarthy, Allan; Lynch, Timothy; McFarland, Robert; Schaefer, Andrew M; Turnbull, Douglass M; Horvath, Rita; Taylor, Robert W; Chinnery, Patrick F

    2014-05-01

    Despite being a canonical presenting feature of mitochondrial disease, the genetic basis of progressive external ophthalmoplegia remains unknown in a large proportion of patients. Here we show that mutations in SPG7 are a novel cause of progressive external ophthalmoplegia associated with multiple mitochondrial DNA deletions. After excluding known causes, whole exome sequencing, targeted Sanger sequencing and multiplex ligation-dependent probe amplification analysis were used to study 68 adult patients with progressive external ophthalmoplegia either with or without multiple mitochondrial DNA deletions in skeletal muscle. Nine patients (eight probands) were found to carry compound heterozygous SPG7 mutations, including three novel mutations: two missense mutations c.2221G>A; p.(Glu741Lys), c.2224G>A; p.(Asp742Asn), a truncating mutation c.861dupT; p.Asn288*, and seven previously reported mutations. We identified a further six patients with single heterozygous mutations in SPG7, including two further novel mutations: c.184-3C>T (predicted to remove a splice site before exon 2) and c.1067C>T; p.(Thr356Met). The clinical phenotype typically developed in mid-adult life with either progressive external ophthalmoplegia/ptosis and spastic ataxia, or a progressive ataxic disorder. Dysphagia and proximal myopathy were common, but urinary symptoms were rare, despite the spasticity. Functional studies included transcript analysis, proteomics, mitochondrial network analysis, single fibre mitochondrial DNA analysis and deep re-sequencing of mitochondrial DNA. SPG7 mutations caused increased mitochondrial biogenesis in patient muscle, and mitochondrial fusion in patient fibroblasts associated with the clonal expansion of mitochondrial DNA mutations. In conclusion, the SPG7 gene should be screened in patients in whom a disorder of mitochondrial DNA maintenance is suspected when spastic ataxia is prominent. The complex neurological phenotype is likely a result of the clonal

  20. Characterization of mutations causing rifampicin and isoniazid resistance of Mycobacterium tuberculosis in Syria.

    Science.gov (United States)

    Madania, Ammar; Habous, Maya; Zarzour, Hana; Ghoury, Ifad; Hebbo, Barea

    2012-01-01

    In order to characterize mutations causing rifampicin and isoniazid resistance of M. tuberculosis in Syria, 69 rifampicin resistant (Rif(r)) and 72 isoniazid resistant (Inh(r)) isolates were screened for point mutations in hot spots of the rpoB, katG and inhA genes by DNA sequencing and real time PCR. Of 69 Rif(r) isolates, 62 (90%) had mutations in the rifampin resistance determining region (RRDR) of the rpoB gene, with codons 531 (61%), 526 (13%), and 516 (8.7%) being the most commonly mutated. We found two new mutations (Asp516Thr and Ser531Gly) described for the first time in the rpoB-RRDR in association with rifampicin resistance. Only one mutation (Ile572Phe) was found outside the rpoB-RRDR. Of 72 Inh(r) strains, 30 (41.6%) had a mutation in katGcodon315 (with Ser315Thr being the predominant alteration), and 23 (32%) harbored the inhA(-15C-->T) mutation. While the general pattern of rpoB-RRDR and katG mutations reflected those found worldwide, the prevalence of the inhA(-15C-->T mutation was above the value found in most other countries, emphasizing the great importance of testing the inhA(-15C-->T) mutation for prediction of isoniazid resistance in Syria. Sensitivity of a rapid test using real time PCR and 3'-Minor groove binder (MGB) probes in detecting Rif(r) and Inh(r) isolates was 90% and 69.4%, respectively. This demonstrates that a small set of MGB-probes can be used in real time PCR in order to detect most mutations causing resistance to rifampicin and isoniazid.

  1. Splice, insertion-deletion and nonsense mutations that perturb the phenylalanine hydroxylase transcript cause phenylketonuria in India.

    Science.gov (United States)

    Bashyam, Murali D; Chaudhary, Ajay K; Kiran, Manjari; Nagarajaram, Hampapathalu A; Devi, Radha Rama; Ranganath, Prajnya; Dalal, Ashwin; Bashyam, Leena; Gupta, Neerja; Kabra, Madhulika; Muranjan, Mamta; Puri, Ratna D; Verma, Ishwar C; Nampoothiri, Sheela; Kadandale, Jayarama S

    2014-03-01

    Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by mutational inactivation of the phenylalanine hydroxylase (PAH) gene. Missense mutations are the most common PAH mutation type detected in PKU patients worldwide. We performed PAH mutation analysis in 27 suspected Indian PKU families (including 7 from our previous study) followed by structure and function analysis of specific missense and splice/insertion-deletion/nonsense mutations, respectively. Of the 27 families, disease-causing mutations were detected in 25. A total of 20 different mutations were identified of which 7 "unique" mutations accounted for 13 of 25 mutation positive families. The unique mutations detected exclusively in Indian PKU patients included three recurrent mutations detected in three families each. The 20 mutations included only 5 missense mutations in addition to 5 splice, 4 each nonsense and insertion-deletion mutations, a silent variant in coding region and a 3'UTR mutation. One deletion and two nonsense mutations were characterized to confirm significant reduction in mutant transcript levels possibly through activation of nonsense mediated decay. All missense mutations affected conserved amino acid residues and sequence and structure analysis suggested significant perturbations in the enzyme activity of respective mutant proteins. This is probably the first report of identification of a significantly low proportion of missense PAH mutations from PKU families and together with the presence of a high proportion of splice, insertion-deletion, and nonsense mutations, points to a unique PAH mutation profile in Indian PKU patients.

  2. Exome Sequencing Reveals Cubilin Mutation as a Single-Gene Cause of Proteinuria

    Science.gov (United States)

    Ovunc, Bugsu; Otto, Edgar A.; Vega-Warner, Virginia; Saisawat, Pawaree; Ashraf, Shazia; Ramaswami, Gokul; Fathy, Hanan M.; Schoeb, Dominik; Chernin, Gil; Lyons, Robert H.; Yilmaz, Engin

    2011-01-01

    In two siblings of consanguineous parents with intermittent nephrotic-range proteinuria, we identified a homozygous deleterious frameshift mutation in the gene CUBN, which encodes cubulin, using exome capture and massively parallel re-sequencing. The mutation segregated with affected members of this family and was absent from 92 healthy individuals, thereby identifying a recessive mutation in CUBN as the single-gene cause of proteinuria in this sibship. Cubulin mutations cause a hereditary form of megaloblastic anemia secondary to vitamin B12 deficiency, and proteinuria occurs in 50% of cases since cubilin is coreceptor for both the intestinal vitamin B12-intrinsic factor complex and the tubular reabsorption of protein in the proximal tubule. In summary, we report successful use of exome capture and massively parallel re-sequencing to identify a rare, single-gene cause of nephropathy. PMID:21903995

  3. Exome sequencing reveals cubilin mutation as a single-gene cause of proteinuria.

    Science.gov (United States)

    Ovunc, Bugsu; Otto, Edgar A; Vega-Warner, Virginia; Saisawat, Pawaree; Ashraf, Shazia; Ramaswami, Gokul; Fathy, Hanan M; Schoeb, Dominik; Chernin, Gil; Lyons, Robert H; Yilmaz, Engin; Hildebrandt, Friedhelm

    2011-10-01

    In two siblings of consanguineous parents with intermittent nephrotic-range proteinuria, we identified a homozygous deleterious frameshift mutation in the gene CUBN, which encodes cubulin, using exome capture and massively parallel re-sequencing. The mutation segregated with affected members of this family and was absent from 92 healthy individuals, thereby identifying a recessive mutation in CUBN as the single-gene cause of proteinuria in this sibship. Cubulin mutations cause a hereditary form of megaloblastic anemia secondary to vitamin B(12) deficiency, and proteinuria occurs in 50% of cases since cubilin is coreceptor for both the intestinal vitamin B(12)-intrinsic factor complex and the tubular reabsorption of protein in the proximal tubule. In summary, we report successful use of exome capture and massively parallel re-sequencing to identify a rare, single-gene cause of nephropathy.

  4. Mutation of Elfn1 in mice causes seizures and hyperactivity.

    Science.gov (United States)

    Dolan, Jackie; Mitchell, Kevin J

    2013-01-01

    A growing number of proteins with extracellular leucine-rich repeats (eLRRs) have been implicated in directing neuronal connectivity. We previously identified a novel family of eLRR proteins in mammals: the Elfns are transmembrane proteins with 6 LRRs, a fibronectin type-3 domain and a long cytoplasmic tail. The recent discovery that Elfn1 protein, expressed postsynaptically, can direct the elaboration of specific electrochemical properties of synapses between particular cell types in the hippocampus strongly reinforces this hypothesis. Here, we present analyses of an Elfn1 mutant mouse line and demonstrate a functional requirement for this gene in vivo. We first carried out detailed expression analysis of Elfn1 using a β-galactosidase reporter gene in the knockout line. Elfn1 is expressed in distinct subsets of interneurons of the hippocampus and cortex, and also in discrete subsets of cells in the habenula, septum, globus pallidus, dorsal subiculum, amygdala and several other regions. Elfn1 is expressed in diverse cell types, including local GABAergic interneurons as well as long-range projecting GABAergic and glutamatergic neurons. Elfn1 protein localises to axons of excitatory neurons in the habenula, and long-range GABAergic neurons of the globus pallidus, suggesting the possibility of additional roles for Elfn1 in axons or presynaptically. While gross anatomical analyses did not reveal any obvious neuroanatomical abnormalities, behavioural analyses clearly illustrate functional effects of Elfn1 mutation. Elfn1 mutant mice exhibit seizures, subtle motor abnormalities, reduced thigmotaxis and hyperactivity. The hyperactivity is paradoxically reversible by treatment with the stimulant amphetamine, consistent with phenotypes observed in animals with habenular lesions. These analyses reveal a requirement for Elfn1 in brain function and are suggestive of possible relevance to the etiology and pathophysiology of epilepsy and attention-deficit hyperactivity disorder.

  5. Mutation of Elfn1 in mice causes seizures and hyperactivity.

    Directory of Open Access Journals (Sweden)

    Jackie Dolan

    Full Text Available A growing number of proteins with extracellular leucine-rich repeats (eLRRs have been implicated in directing neuronal connectivity. We previously identified a novel family of eLRR proteins in mammals: the Elfns are transmembrane proteins with 6 LRRs, a fibronectin type-3 domain and a long cytoplasmic tail. The recent discovery that Elfn1 protein, expressed postsynaptically, can direct the elaboration of specific electrochemical properties of synapses between particular cell types in the hippocampus strongly reinforces this hypothesis. Here, we present analyses of an Elfn1 mutant mouse line and demonstrate a functional requirement for this gene in vivo. We first carried out detailed expression analysis of Elfn1 using a β-galactosidase reporter gene in the knockout line. Elfn1 is expressed in distinct subsets of interneurons of the hippocampus and cortex, and also in discrete subsets of cells in the habenula, septum, globus pallidus, dorsal subiculum, amygdala and several other regions. Elfn1 is expressed in diverse cell types, including local GABAergic interneurons as well as long-range projecting GABAergic and glutamatergic neurons. Elfn1 protein localises to axons of excitatory neurons in the habenula, and long-range GABAergic neurons of the globus pallidus, suggesting the possibility of additional roles for Elfn1 in axons or presynaptically. While gross anatomical analyses did not reveal any obvious neuroanatomical abnormalities, behavioural analyses clearly illustrate functional effects of Elfn1 mutation. Elfn1 mutant mice exhibit seizures, subtle motor abnormalities, reduced thigmotaxis and hyperactivity. The hyperactivity is paradoxically reversible by treatment with the stimulant amphetamine, consistent with phenotypes observed in animals with habenular lesions. These analyses reveal a requirement for Elfn1 in brain function and are suggestive of possible relevance to the etiology and pathophysiology of epilepsy and attention

  6. Mutation of ATF6 causes autosomal recessive achromatopsia.

    Science.gov (United States)

    Ansar, Muhammad; Santos-Cortez, Regie Lyn P; Saqib, Muhammad Arif Nadeem; Zulfiqar, Fareeha; Lee, Kwanghyuk; Ashraf, Naeem Mahmood; Ullah, Ehsan; Wang, Xin; Sajid, Sundus; Khan, Falak Sher; Amin-ud-Din, Muhammad; Smith, Joshua D; Shendure, Jay; Bamshad, Michael J; Nickerson, Deborah A; Hameed, Abdul; Riazuddin, Saima; Ahmed, Zubair M; Ahmad, Wasim; Leal, Suzanne M

    2015-09-01

    Achromatopsia (ACHM) is an early-onset retinal dystrophy characterized by photophobia, nystagmus, color blindness and severely reduced visual acuity. Currently mutations in five genes CNGA3, CNGB3, GNAT2, PDE6C and PDE6H have been implicated in ACHM. We performed homozygosity mapping and linkage analysis in a consanguineous Pakistani ACHM family and mapped the locus to a 15.12-Mb region on chromosome 1q23.1-q24.3 with a maximum LOD score of 3.6. A DNA sample from an affected family member underwent exome sequencing. Within the ATF6 gene, a single-base insertion variant c.355_356dupG (p.Glu119Glyfs*8) was identified, which completely segregates with the ACHM phenotype within the family. The frameshift variant was absent in public variant databases, in 130 exomes from unrelated Pakistani individuals, and in 235 ethnically matched controls. The variant is predicted to result in a truncated protein that lacks the DNA binding and transmembrane domains and therefore affects the function of ATF6 as a transcription factor that initiates the unfolded protein response during endoplasmic reticulum (ER) stress. Immunolabeling with anti-ATF6 antibodies showed localization throughout the mouse neuronal retina, including retinal pigment epithelium, photoreceptor cells, inner nuclear layer, inner and outer plexiform layers, with a more prominent signal in retinal ganglion cells. In contrast to cytoplasmic expression of wild-type protein, in heterologous cells ATF6 protein with the p.Glu119Glyfs*8 variant is mainly confined to the nucleus. Our results imply that response to ER stress as mediated by the ATF6 pathway is essential for color vision in humans.

  7. In silico investigation of molecular effects caused by missense mutations in creatine transporter protein

    Science.gov (United States)

    Zhang, Zhe; Schwatz, Charles; Alexov, Emil

    2011-03-01

    Creatine transporter (CT) protein, which is encoded by SLC6A8 gene, is essential for taking up the creatine in the cell, which in turn plays a key role in the spatial and temporal maintenance of energy in skeletal and cardiac muscle cells. It was shown that some missense mutations in CT cause mental retardation, while others are harmless non-synonymous single nucleoside polymorphism (nsSNP). Currently fifteen missense mutations in CT are known, among which twelve are disease-causing. Sequence analysis reveals that there is no clear trend distinguishing disease-causing from harmless missense mutations. Because of that, we built 3D model of the CT using highly homologous template and use the model to investigate the effects of mutations of CT stability and hydrogen bond network. It is demonstrated that disease-causing mutations affect the folding free energy and ionization states of titratable group in much greater extend as compared with harmless mutations. Supported by grants from NLM, NIH, grant numbers 1R03LM009748 and 1R03LM009748-S1.

  8. A novel mitochondrial MTND5 frameshift mutation causing isolated complex I deficiency, renal failure and myopathy.

    Science.gov (United States)

    Alston, Charlotte L; Morak, Monika; Reid, Christopher; Hargreaves, Iain P; Pope, Simon A S; Land, John M; Heales, Simon J; Horvath, Rita; Mundy, Helen; Taylor, Robert W

    2010-02-01

    Isolated complex I deficiency is the most commonly reported enzyme defect in paediatric mitochondrial disorders, and may arise due to mutations in nuclear-encoded structural or assembly genes, or the mitochondrial genome. We present the clinical, biochemical and molecular genetic data in a young girl whose clinical picture is dominated by chronic renal failure, myopathy and persistent lactic acidosis. An isolated complex I deficiency in muscle was identified due to a novel mutation (m.12425delA) in the MTND5 gene. This single nucleotide deletion is heteroplasmic and detectable in several tissues from the proband but not her mother, suggesting a de novo mutation event. The description of the first frameshift mutation in a mitochondrial complex I gene affirms mitochondrial DNA mutations as an important cause of isolated complex I deficiency in children and the importance of whole mitochondrial genome sequencing in the diagnostic work-up to elucidate the underlying molecular genetic abnormality and provide important genetic advice.

  9. No muscle involvement in myoclonus-dystonia caused by epsilon-sarcoglycan gene mutations1

    DEFF Research Database (Denmark)

    Hjermind, L.E.; Vissing, J.; Asmus, F.;

    2008-01-01

    Mutations in the epsilon-sarcoglycan gene (SGCE) can cause autosomal dominant inherited myoclonus-dystonia (M-D). Defects in other sarcoglycans; alpha-, beta-, gamma-, and delta can cause autosomal recessive inherited limb girdle muscular dystrophies. epsilon- and alpha-sarcoglycans are very...... homologous and may substitute for one-another in different tissues. We therefore investigated whether mutations in SGCE also cause abnormalities of skeletal and myocardial muscle. Six patients with clinically and genetically verified M-D and no signs of limb-girdle muscular dystrophy were included. Skeletal...

  10. Chromatin remodeling by the CHD7 protein is impaired by mutations that cause human developmental disorders.

    Science.gov (United States)

    Bouazoune, Karim; Kingston, Robert E

    2012-11-20

    Mutations in the CHD7 gene cause human developmental disorders including CHARGE syndrome. Genetic studies in model organisms have further established CHD7 as a central regulator of vertebrate development. Functional analysis of the CHD7 protein has been hampered by its large size. We used a dual-tag system to purify intact recombinant CHD7 protein and found that it is an ATP-dependent nucleosome remodeling factor. Biochemical analyses indicate that CHD7 has characteristics distinct from SWI/SNF- and ISWI-type remodelers. Further investigations show that CHD7 patient mutations have consequences that range from subtle to complete inactivation of remodeling activity, and that mutations leading to protein truncations upstream of amino acid 1899 of CHD7 are likely to cause a hypomorphic phenotype for remodeling. We propose that nucleosome remodeling is a key function for CHD7 during developmental processes and provide a molecular basis for predicting the impact of disease mutations on that function.

  11. Nemaline myopathy caused byTNNT1 mutations in a Dutch pedigree.

    Science.gov (United States)

    van der Pol, W Ludo; Leijenaar, Jolien F; Spliet, Wim G M; Lavrijsen, Selma W; Jansen, Nicolaas J G; Braun, Kees P J; Mulder, Marcel; Timmers-Raaijmakers, Brigitte; Ratsma, Kimberly; Dooijes, Dennis; van Haelst, Mieke M

    2014-03-01

    Nemaline myopathy (NM) is genetically heterogeneous disorder characterized by early onset muscular weakness and sarcoplasmatic or intranuclear inclusions of rod-shaped Z-disk material in muscle fibers. Thus far, mutations in seven genes have been identified as cause of NM. Only one singleTNNT1 nonsense mutation has been previously described that causes autosomal recessive NM in the old order Amish with a very specific clinical phenotype including rapidly progressive contractures. Here, we report a patient who is compound heterozygous for a c.309+1G>A mutation and an exon 14 deletion in theTNNT1 gene. This report confirms the specific clinical phenotype ofTNNT1 NM and documents two newTNNT1 mutations outside the old order Amish.

  12. Reciprocal sign epistasis between frequently experimentally evolved adaptive mutations causes a rugged fitness landscape.

    Directory of Open Access Journals (Sweden)

    Daniel J Kvitek

    2011-04-01

    Full Text Available The fitness landscape captures the relationship between genotype and evolutionary fitness and is a pervasive metaphor used to describe the possible evolutionary trajectories of adaptation. However, little is known about the actual shape of fitness landscapes, including whether valleys of low fitness create local fitness optima, acting as barriers to adaptive change. Here we provide evidence of a rugged molecular fitness landscape arising during an evolution experiment in an asexual population of Saccharomyces cerevisiae. We identify the mutations that arose during the evolution using whole-genome sequencing and use competitive fitness assays to describe the mutations individually responsible for adaptation. In addition, we find that a fitness valley between two adaptive mutations in the genes MTH1 and HXT6/HXT7 is caused by reciprocal sign epistasis, where the fitness cost of the double mutant prohibits the two mutations from being selected in the same genetic background. The constraint enforced by reciprocal sign epistasis causes the mutations to remain mutually exclusive during the experiment, even though adaptive mutations in these two genes occur several times in independent lineages during the experiment. Our results show that epistasis plays a key role during adaptation and that inter-genic interactions can act as barriers between adaptive solutions. These results also provide a new interpretation on the classic Dobzhansky-Muller model of reproductive isolation and display some surprising parallels with mutations in genes often associated with tumors.

  13. Reciprocal sign epistasis between frequently experimentally evolved adaptive mutations causes a rugged fitness landscape.

    Directory of Open Access Journals (Sweden)

    Daniel J Kvitek

    2011-04-01

    Full Text Available The fitness landscape captures the relationship between genotype and evolutionary fitness and is a pervasive metaphor used to describe the possible evolutionary trajectories of adaptation. However, little is known about the actual shape of fitness landscapes, including whether valleys of low fitness create local fitness optima, acting as barriers to adaptive change. Here we provide evidence of a rugged molecular fitness landscape arising during an evolution experiment in an asexual population of Saccharomyces cerevisiae. We identify the mutations that arose during the evolution using whole-genome sequencing and use competitive fitness assays to describe the mutations individually responsible for adaptation. In addition, we find that a fitness valley between two adaptive mutations in the genes MTH1 and HXT6/HXT7 is caused by reciprocal sign epistasis, where the fitness cost of the double mutant prohibits the two mutations from being selected in the same genetic background. The constraint enforced by reciprocal sign epistasis causes the mutations to remain mutually exclusive during the experiment, even though adaptive mutations in these two genes occur several times in independent lineages during the experiment. Our results show that epistasis plays a key role during adaptation and that inter-genic interactions can act as barriers between adaptive solutions. These results also provide a new interpretation on the classic Dobzhansky-Muller model of reproductive isolation and display some surprising parallels with mutations in genes often associated with tumors.

  14. SAAMBE: Webserver to Predict the Charge of Binding Free Energy Caused by Amino Acids Mutations.

    Science.gov (United States)

    Petukh, Marharyta; Dai, Luogeng; Alexov, Emil

    2016-04-12

    Predicting the effect of amino acid substitutions on protein-protein affinity (typically evaluated via the change of protein binding free energy) is important for both understanding the disease-causing mechanism of missense mutations and guiding protein engineering. In addition, researchers are also interested in understanding which energy components are mostly affected by the mutation and how the mutation affects the overall structure of the corresponding protein. Here we report a webserver, the Single Amino Acid Mutation based change in Binding free Energy (SAAMBE) webserver, which addresses the demand for tools for predicting the change of protein binding free energy. SAAMBE is an easy to use webserver, which only requires that a coordinate file be inputted and the user is provided with various, but easy to navigate, options. The user specifies the mutation position, wild type residue and type of mutation to be made. The server predicts the binding free energy change, the changes of the corresponding energy components and provides the energy minimized 3D structure of the wild type and mutant proteins for download. The SAAMBE protocol performance was tested by benchmarking the predictions against over 1300 experimentally determined changes of binding free energy and a Pearson correlation coefficient of 0.62 was obtained. How the predictions can be used for discriminating disease-causing from harmless mutations is discussed. The webserver can be accessed via http://compbio.clemson.edu/saambe_webserver/.

  15. Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

    DEFF Research Database (Denmark)

    Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro;

    2015-01-01

    involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients......, although with variable extent and severity of lesions. In the upper girdle, the subscapularis muscle was invariably affected. In the lower limbs, all the patients showed a consistent involvement of the flexor hallucis longus, which is very rarely affected in other muscle diseases, and a diffuse involvement...

  16. Novel mutation in KCNA1 causes episodic ataxia with paroxysmal dyspnea.

    Science.gov (United States)

    Shook, Steven J; Mamsa, Hafsa; Jen, Joanna C; Baloh, Robert W; Zhou, Lan

    2008-03-01

    Episodic ataxia type 1 (EA1) is an autosomal-dominant neurological disease caused by point mutations in the potassium channel-encoding gene KCNA1. It is characterized by attacks of ataxia and continuous myokymia. Respiratory muscle involvement has not been previously reported in EA1. We clinically evaluated a family with features of EA1 and paroxysmal shortness of breath. Coding and flanking intronic regions of KCNA1 were sequenced. We identified a novel 3-nucleotide deletion mutation in KCNA1 in the affected individuals. Our findings of a deletion mutation with unusual respiratory muscle involvement expand the genetic and clinical spectrum of EA1.

  17. A Novel CRYBB2 Stopgain Mutation Causing Congenital Autosomal Dominant Cataract in a Chinese Family

    Directory of Open Access Journals (Sweden)

    Yu Zhou

    2016-01-01

    Full Text Available Congenital cataract is the most common cause of the visual disability and blindness in childhood. This study aimed to identify gene mutations responsible for autosomal dominant congenital cataract (ADCC in a Chinese family using next-generation sequencing technology. This family included eight unaffected and five affected individuals. After complete ophthalmic examinations, the blood samples of the proband and two available family members were collected. Then the whole exome sequencing was performed on the proband and Sanger sequencing was applied to validate the causal mutation in the two family members and control samples. After the whole exome sequencing data were filtered through a series of existing variation databases, a heterozygous mutation c.499Tmutation cosegregated with the disease phenotype in the family and was absolutely absent in 1000 ethnicity-matched control samples. Thus, the heterozygous mutation c.499Tmutation responsible for this ADCC family. In conclusion, our findings revealed a novel stopgain mutation c.499Tmutation spectrum of CRYBB2 in Chinese congenital cataract population and illustrated the important role of CRYBB2 in the genetics research of congenital cataract.

  18. GRIN1 mutations cause encephalopathy with infantile-onset epilepsy, and hyperkinetic and stereotyped movement disorders.

    Science.gov (United States)

    Ohba, Chihiro; Shiina, Masaaki; Tohyama, Jun; Haginoya, Kazuhiro; Lerman-Sagie, Tally; Okamoto, Nobuhiko; Blumkin, Lubov; Lev, Dorit; Mukaida, Souichi; Nozaki, Fumihito; Uematsu, Mitsugu; Onuma, Akira; Kodera, Hirofumi; Nakashima, Mitsuko; Tsurusaki, Yoshinori; Miyake, Noriko; Tanaka, Fumiaki; Kato, Mitsuhiro; Ogata, Kazuhiro; Saitsu, Hirotomo; Matsumoto, Naomichi

    2015-06-01

    Recently, de novo mutations in GRIN1 have been identified in patients with nonsyndromic intellectual disability and epileptic encephalopathy. Whole exome sequencing (WES) analysis of patients with genetically unsolved epileptic encephalopathies identified four patients with GRIN1 mutations, allowing us to investigate the phenotypic spectrum of GRIN1 mutations. Eighty-eight patients with unclassified early onset epileptic encephalopathies (EOEEs) with an age of onset stereotypic hand movements were observed in two and three patients, respectively. All the four patients exhibited only nonspecific focal and diffuse epileptiform abnormality, and never showed suppression-burst or hypsarrhythmia during infancy. A de novo mosaic mutation (c.1923G>A) with a mutant allele frequency of 16% (in DNA of blood leukocytes) was detected in one patient. Three mutations were located in the transmembrane domain (3/4, 75%), and one in the extracellular loop near transmembrane helix 1. All the mutations were predicted to impair the function of the NMDA receptor. Clinical features of de novo GRIN1 mutations include infantile involuntary movements, seizures, and hand stereotypies, suggesting that GRIN1 mutations cause encephalopathy resulting in seizures and movement disorders. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

  19. A novel ICK mutation causes ciliary disruption and lethal endocrine-cerebro-osteodysplasia syndrome

    OpenAIRE

    Kayserili Karabey, Hülya; Oud, M.M.; Bonnard, C.; Mans, D.A.; Altunoğlu, U.; Tohari, S.; Ng, A.Y.J.; Eskin, A.; Lee, H.; Rupar, C.A.; Wagenaar, N.P.; Wu, K.M.; Lahiry, P.; Pazour, G.J.; Nelson, S.F.; Hegele, R.A.; Roepman, R; Venkatesh, B.; Siu, V.M.; Reversade, B.; Arts, H.H.

    2016-01-01

    Background: Endocrine-cerebro-osteodysplasia (ECO) syndrome [MIM:612651] caused by a recessive mutation (p.R272Q) in Intestinal cell kinase (ICK) shows significant clinical overlap with ciliary disorders. Similarities are strongest between ECO syndrome, the Majewski and Mohr-Majewski short-rib thoracic dysplasia (SRTD) with polydactyly syndromes, and hydrolethalus syndrome. In this study, we present a novel homozygous ICK mutation in a fetus with ECO syndrome and compare the effect of this mu...

  20. Inherited Cardiac Diseases Caused by Mutations in the Nav1.5 Sodium Channel

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Jacob; Winkel, Bo Gregers; Grunnet, Morten

    2009-01-01

    Cardiac Diseases Caused by SCN5A Mutations. A prerequisite for a normal cardiac function is a proper generation and propagation of electrical impulses. Contraction of the heart is obtained through a delicate matched transmission of the electrical impulses. A pivotal element of the impulse propaga......-QT syndrome, Brugada syndrome, and AF, reported to be associated with mutations in SCN5A, are thoroughly described. (J Cardiovasc Electrophysiol, Vol. pp. 1-9)....

  1. Autosomal-Dominant Multiple Pterygium Syndrome Is Caused by Mutations in MYH3.

    Science.gov (United States)

    Chong, Jessica X; Burrage, Lindsay C; Beck, Anita E; Marvin, Colby T; McMillin, Margaret J; Shively, Kathryn M; Harrell, Tanya M; Buckingham, Kati J; Bacino, Carlos A; Jain, Mahim; Alanay, Yasemin; Berry, Susan A; Carey, John C; Gibbs, Richard A; Lee, Brendan H; Krakow, Deborah; Shendure, Jay; Nickerson, Deborah A; Bamshad, Michael J

    2015-05-01

    Multiple pterygium syndrome (MPS) is a phenotypically and genetically heterogeneous group of rare Mendelian conditions characterized by multiple pterygia, scoliosis, and congenital contractures of the limbs. MPS typically segregates as an autosomal-recessive disorder, but rare instances of autosomal-dominant transmission have been reported. Whereas several mutations causing recessive MPS have been identified, the genetic basis of dominant MPS remains unknown. We identified four families affected by dominantly transmitted MPS characterized by pterygia, camptodactyly of the hands, vertebral fusions, and scoliosis. Exome sequencing identified predicted protein-altering mutations in embryonic myosin heavy chain (MYH3) in three families. MYH3 mutations underlie distal arthrogryposis types 1, 2A, and 2B, but all mutations reported to date occur in the head and neck domains. In contrast, two of the mutations found to cause MPS in this study occurred in the tail domain. The phenotypic overlap among persons with MPS, coupled with physical findings distinct from other conditions caused by mutations in MYH3, suggests that the developmental mechanism underlying MPS differs from that of other conditions and/or that certain functions of embryonic myosin might be perturbed by disruption of specific residues and/or domains. Moreover, the vertebral fusions in persons with MPS, coupled with evidence of MYH3 expression in bone, suggest that embryonic myosin plays a role in skeletal development.

  2. Cap +1 mutation; an unsuspected cause of beta thalassaemia transmission in Pakistan

    Directory of Open Access Journals (Sweden)

    Sadia Usman Babar

    2009-12-01

    Full Text Available Objective: Thalassemia is one of the most common genetic disorders worldwide. Cap +1 mutation which causes ‘silent beta thalassemia’ is present around all ethnic groups of Pakistan. This study was designed to detect the frequency of Cap+1 mutation in Pakistani Population.Materials and Methods: Molecular genetic for Cap+1 beta thalassemic mutation was done by extracting DNA from whole blood by using Genomic DNA Purification Kit (Gentra system USA. Amplification Refractory Mutation System (ARMS primers were designed for detection of normal and mutant DNA.Basic hematological parameters were performed by using automated analyzer (Sysmex KX-21. Cellulose acetate hemoglobin electrophoresis was done by using semi-automated technique (INTERLAB Roma Microtech Series Electrophoresis system 4.23. Results: The frequency of Cap+1 mutation was observed 5% (10/200 in targeted thalassemic families (having patients with beta-thalassemia intermedia while its frequency was observed 2% (12/600 in total thalassemic genes in Pakistani population. Conclusion: Cap+1 (A-C is a silent mutation and it has very minimum effect on beta globin synthesis because of which it produces very less clinical severity and certain important laboratory diagnostic tests like basic hematological parameters and Hb A2 levels are also remain in normal range. Therefore individuals with Cap+1 mutation may produce children with beta-thalassemia intermedia if they marry an individual with beta-thalassemia minor. Cap+1 (A-C mutation is an unsuspected cause of beta thalassemia transmission in Pakistani population. This mutation can identify at molecular level. As this molecular defect is difficult to diagnose in Laboratory with routine laboratory tests because of that it has become a serious hindrance for thalassemia prevention program in Pakistan.

  3. Mutations in MME cause an autosomal‐recessive Charcot–Marie–Tooth disease type 2

    Science.gov (United States)

    Higuchi, Yujiro; Hashiguchi, Akihiro; Yuan, Junhui; Yoshimura, Akiko; Mitsui, Jun; Ishiura, Hiroyuki; Tanaka, Masaki; Ishihara, Satoshi; Tanabe, Hajime; Nozuma, Satoshi; Okamoto, Yuji; Matsuura, Eiji; Ohkubo, Ryuichi; Inamizu, Saeko; Shiraishi, Wataru; Yamasaki, Ryo; Ohyagi, Yasumasa; Kira, Jun‐ichi; Oya, Yasushi; Yabe, Hayato; Nishikawa, Noriko; Tobisawa, Shinsuke; Matsuda, Nozomu; Masuda, Masayuki; Kugimoto, Chiharu; Fukushima, Kazuhiro; Yano, Satoshi; Yoshimura, Jun; Doi, Koichiro; Nakagawa, Masanori; Morishita, Shinichi; Tsuji, Shoji

    2016-01-01

    Objective The objective of this study was to identify new causes of Charcot–Marie–Tooth (CMT) disease in patients with autosomal‐recessive (AR) CMT. Methods To efficiently identify novel causative genes for AR‐CMT, we analyzed 303 unrelated Japanese patients with CMT using whole‐exome sequencing and extracted recessive variants/genes shared among multiple patients. We performed mutation screening of the newly identified membrane metalloendopeptidase (MME) gene in 354 additional patients with CMT. We clinically, genetically, pathologically, and radiologically examined 10 patients with the MME mutation. Results We identified recessive mutations in MME in 10 patients. The MME gene encodes neprilysin (NEP), which is well known to be one of the most prominent beta‐amyloid (Aβ)‐degrading enzymes. All patients had a similar phenotype consistent with late‐onset axonal neuropathy. They showed muscle weakness, atrophy, and sensory disturbance in the lower extremities. All the MME mutations could be loss‐of‐function mutations, and we confirmed a lack/decrease of NEP protein expression in a peripheral nerve. No patients showed symptoms of dementia, and 1 patient showed no excess Aβ in Pittsburgh compound‐B positron emission tomography imaging. Interpretation Our results indicate that loss‐of‐function MME mutations are the most frequent cause of adult‐onset AR‐CMT2 in Japan, and we propose that this new disease should be termed AR‐CMT2T. A loss‐of‐function MME mutation did not cause early‐onset Alzheimer's disease. Identifying the MME mutation responsible for AR‐CMT could improve the rate of molecular diagnosis and the understanding of the molecular mechanisms of CMT. Ann Neurol 2016;79:659–672 PMID:26991897

  4. Cataracts and microphthalmia caused by a Gja8 mutation in extracellular loop 2.

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    Chun-Hong Xia

    Full Text Available The mouse semi-dominant Nm2249 mutation displays variable cataracts in heterozygous mice and smaller lenses with severe cataracts in homozygous mice. This mutation is caused by a Gja8(R205G point mutation in the second extracellular loop of the Cx50 (or α8 connexin protein. Immunohistological data reveal that Cx50-R205G mutant proteins and endogenous wild-type Cx46 (or α3 connexin proteins form diffuse tiny spots rather than typical punctate signals of normal gap junctions in the lens. The level of phosphorylated Cx46 proteins is decreased in Gja8(R205G/R205G mutant lenses. Genetic analysis reveals that the Cx50-R205G mutation needs the presence of wild-type Cx46 to disrupt lens peripheral fibers and epithelial cells. Electrophysiological data in Xenopus oocytes reveal that Cx50-R205G mutant proteins block channel function of gap junctions composed of wild-type Cx50, but only affect the gating of wild-type Cx46 channels. Both genetic and electrophysiological results suggest that Cx50-R205G mutant proteins alone are unable to form functional channels. These findings imply that the Gja8(R205G mutation differentially impairs the functions of Cx50 and Cx46 to cause cataracts, small lenses and microphthalmia. The Gja8(R205G mutation occurs at the same conserved residue as the human GJA8(R198W mutation. This work provides molecular insights to understand the cataract and microphthalmia/microcornea phenotype caused by Gja8 mutations in mice and humans.

  5. Cataracts and microphthalmia caused by a Gja8 mutation in extracellular loop 2.

    Science.gov (United States)

    Xia, Chun-Hong; Chang, Bo; Derosa, Adam M; Cheng, Catherine; White, Thomas W; Gong, Xiaohua

    2012-01-01

    The mouse semi-dominant Nm2249 mutation displays variable cataracts in heterozygous mice and smaller lenses with severe cataracts in homozygous mice. This mutation is caused by a Gja8(R205G) point mutation in the second extracellular loop of the Cx50 (or α8 connexin) protein. Immunohistological data reveal that Cx50-R205G mutant proteins and endogenous wild-type Cx46 (or α3 connexin) proteins form diffuse tiny spots rather than typical punctate signals of normal gap junctions in the lens. The level of phosphorylated Cx46 proteins is decreased in Gja8(R205G/R205G) mutant lenses. Genetic analysis reveals that the Cx50-R205G mutation needs the presence of wild-type Cx46 to disrupt lens peripheral fibers and epithelial cells. Electrophysiological data in Xenopus oocytes reveal that Cx50-R205G mutant proteins block channel function of gap junctions composed of wild-type Cx50, but only affect the gating of wild-type Cx46 channels. Both genetic and electrophysiological results suggest that Cx50-R205G mutant proteins alone are unable to form functional channels. These findings imply that the Gja8(R205G) mutation differentially impairs the functions of Cx50 and Cx46 to cause cataracts, small lenses and microphthalmia. The Gja8(R205G) mutation occurs at the same conserved residue as the human GJA8(R198W) mutation. This work provides molecular insights to understand the cataract and microphthalmia/microcornea phenotype caused by Gja8 mutations in mice and humans.

  6. Further evidence that mutations in INS can be a rare cause of Maturity-Onset Diabetes of the Young (MODY)

    DEFF Research Database (Denmark)

    Boesgaard, Trine W; Pruhova, Stepanka; Andersson, Ehm A

    2010-01-01

    Insulin gene (INS) mutations have recently been described as a common cause of permanent neonatal diabetes (PNDM) and a rare cause of diabetes diagnosed in childhood or adulthood.......Insulin gene (INS) mutations have recently been described as a common cause of permanent neonatal diabetes (PNDM) and a rare cause of diabetes diagnosed in childhood or adulthood....

  7. Analysis of mutations causing familial hypercholesterolaemia in black South African patients of different ancestry

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    U K Ibe

    2017-02-01

    Full Text Available Background. Familial hypercholesterolaemia (FH is usually caused by mutations in three genes (LDLR, APOB and PCSK9. Objective. To identify the spectrum of FH-causing mutations in black South African (SA patients. Methods. DNA samples of 16 unrelated South African FH patients with elevated low-density lipoprotein cholesterol levels, tendon xanthomas and corneal arcus (3 clinically homozygous FH and 13 heterozygous FH of ethnic African origin were screened for mutations in the LDLR (coding region, promoter and intron/exon boundaries, APOB (part of exon 26 and PCSK9 genes (exon 7, using high-resolution melting. Results. Eight LDLR mutations were identified, for an overall detection rate of 8/19 predicted FH-causing alleles (42.1%. The previously reported six base pair deletion p.(D47_G48del was found in two patients, and two novel variants (c.1187-25T>C and c.1664T>G p.(L555R were found, both predicted to be pathogenic using in silico web-based predictive algorithms. No pathogenic variants in APOB or PCSK9 were found. Conclusions. These findings contribute to the knowledge of allelic heterogeneity in the spectrum of FH-causing mutations in black SA patients, signifying their ancestral diversity. The relatively low overall detection rate may reflect locus heterogeneity of the FH phenotype in black SA FH patients.

  8. Increased progerin expression associated with unusual LMNA mutations causes severe progeroid syndromes.

    Science.gov (United States)

    Moulson, Casey L; Fong, Loren G; Gardner, Jennifer M; Farber, Emily A; Go, Gloriosa; Passariello, Annalisa; Grange, Dorothy K; Young, Stephen G; Miner, Jeffrey H

    2007-09-01

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare precocious aging syndrome caused by mutations in LMNA that lead to synthesis of a mutant form of prelamin A, generally called progerin, that cannot be processed to mature lamin A. Most HGPS patients have a recurrent heterozygous de novo mutation in exon 11 of LMNA, c.1824C>T/p.G608G; this synonymous mutation activates a nearby cryptic splice donor site, resulting in synthesis of the mutant prelamin A, progerin, which lacks 50 amino acids within the carboxyl-terminal domain. Abnormal splicing is incomplete, so the mutant allele produces some normally-spliced transcripts. Nevertheless, the synthesis of progerin is sufficient to cause misshapen nuclei in cultured cells and severe disease phenotypes in affected patients. Here we present two patients with extraordinarily severe forms of progeria caused by unusual mutations in LMNA. One had a splice site mutation (c.1968+1G>A; or IVS11+1G>A), and the other had a novel synonymous coding region mutation (c.1821G>A/p.V607V). Both mutations caused very frequent use of the same exon 11 splice donor site that is activated in typical HGPS patients. As a consequence, the ratios of progerin mRNA and protein to wild-type were higher than in typical HGPS patients. Fibroblasts from both patients exhibited nuclear shape abnormalities typical of HGPS, and cells treated with a protein farnesyltransferase inhibitor exhibited fewer misshapen nuclei. Thus, farnesyltransferase inhibitors may prove to be useful even when progerin expression levels are higher than those in typical HGPS patients.

  9. GPIHBP1 Missense Mutations Often Cause Multimerization of GPIHBP1 and Thereby Prevent Lipoprotein Lipase Binding

    DEFF Research Database (Denmark)

    Beigneux, Anne P; Fong, Loren G; Bensadoun, Andre

    2015-01-01

    Rationale: GPIHBP1, a GPI-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) in the subendothelial spaces and shuttles it to the capillary lumen. GPIHBP1 missense mutations that interfere with LPL binding cause familial chylomicronemia. Objective: We sought to underst......Rationale: GPIHBP1, a GPI-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) in the subendothelial spaces and shuttles it to the capillary lumen. GPIHBP1 missense mutations that interfere with LPL binding cause familial chylomicronemia. Objective: We sought...

  10. Specific filaggrin mutations cause ichthyosis vulgaris and are significantly associated with atopic dermatitis in Japan.

    Science.gov (United States)

    Nomura, Toshifumi; Akiyama, Masashi; Sandilands, Aileen; Nemoto-Hasebe, Ikue; Sakai, Kaori; Nagasaki, Akari; Ota, Mitsuhito; Hata, Hiroo; Evans, Alan T; Palmer, Colin N A; Shimizu, Hiroshi; McLean, W H Irwin

    2008-06-01

    Mutations in the gene encoding filaggrin (FLG) have been identified as the cause of ichthyosis vulgaris (IV) and shown to be major predisposing factors for atopic dermatitis (AD). However, these studies have been mainly carried out in European populations. In early 2007, we identified two Oriental-specific FLG mutations in four Japanese families with IV and reported that filaggrin mutations were also significant predisposing factors for AD in Japan. However, the frequency of FLG mutations observed in our Japanese AD cohort (5.6%), was much lower than that seen in Europeans (up to 48%). Here, we studied a further seven Japanese families with IV and identified two additional nonsense mutations in FLG, S2889X, and S3296X. We found that more than 20% of patients in our Japanese AD case series carry FLG mutations, and there is significant statistical association between the four mutations and AD (chi(2) P=8.4 x 10(-6); heterozygote odds ratio 7.57, 95% CI 2.84-23.03). These data emphasize that skin-barrier impairment due to reduced filaggrin expression plays an important role in the pathogenesis of AD and sheds further light on the genetic architecture of atopy in Japan.

  11. A functional alternative splicing mutation in AIRE gene causes autoimmune polyendocrine syndrome type 1.

    Science.gov (United States)

    Zhang, Junyu; Liu, Hongbin; Liu, Zhiyuan; Liao, Yong; Guo, Luo; Wang, Honglian; He, Lin; Zhang, Xiaodong; Xing, Qinghe

    2013-01-01

    Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare autosomal recessive disease defined by the presence of two of the three conditions: mucocutaneous candidiasis, hypoparathyroidism, and Addison's disease. Loss-of-function mutations of the autoimmune regulator (AIRE) gene have been linked to APS-1. Here we report mutational analysis and functional characterization of an AIRE mutation in a consanguineous Chinese family with APS-1. All exons of the AIRE gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. We identified a homozygous missense AIRE mutation c.463G>A (p.Gly155Ser) in two siblings with different clinical features of APS-1. In silico splice-site prediction and minigene analysis were carried out to study the potential pathological consequence. Minigene splicing analysis and subsequent cDNA sequencing revealed that the AIRE mutation potentially compromised the recognition of the splice donor of intron 3, causing alternative pre-mRNA splicing by intron 3 retention. Furthermore, the aberrant AIRE transcript was identified in a heterozygous carrier of the c.463G>A mutation. The aberrant intron 3-retaining transcript generated a truncated protein (p.G155fsX203) containing the first 154 AIRE amino acids and followed by 48 aberrant amino acids. Therefore, our study represents the first functional characterization of the alternatively spliced AIRE mutation that may explain the pathogenetic role in APS-1.

  12. Do cell junction protein mutations cause an airway phenotype in mice or humans?

    Science.gov (United States)

    Chang, Eugene H; Pezzulo, Alejandro A; Zabner, Joseph

    2011-08-01

    Cell junction proteins connect epithelial cells to each other and to the basement membrane. Genetic mutations of these proteins can cause alterations in some epithelia leading to varied phenotypes such as deafness, renal disease, skin disorders, and cancer. This review examines if genetic mutations in these proteins affect the function of lung airway epithelia. We review cell junction proteins with examples of disease mutation phenotypes in humans and in mouse knockout models. We also review which of these genes are expressed in airway epithelium by microarray expression profiling and immunocytochemistry. Last, we present a comprehensive literature review to find the lung phenotype when cell junction and adhesion genes are mutated or subject to targeted deletion. We found that in murine models, targeted deletion of cell junction and adhesion genes rarely result in a lung phenotype. Moreover, mutations in these genes in humans have no obvious lung phenotype. Our research suggests that simply because a cell junction or adhesion protein is expressed in an organ does not imply that it will exhibit a drastic phenotype when mutated. One explanation is that because a functioning lung is critical to survival, redundancy in the system is expected. Therefore mutations in a single gene might be compensated by a related function of a similar gene product. Further studies in human and animal models will help us understand the overlap in the function of cell junction gene products. Finally, it is possible that the human lung phenotype is subtle and has not yet been described.

  13. A functional alternative splicing mutation in AIRE gene causes autoimmune polyendocrine syndrome type 1.

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    Full Text Available Autoimmune polyendocrine syndrome type 1 (APS-1 is a rare autosomal recessive disease defined by the presence of two of the three conditions: mucocutaneous candidiasis, hypoparathyroidism, and Addison's disease. Loss-of-function mutations of the autoimmune regulator (AIRE gene have been linked to APS-1. Here we report mutational analysis and functional characterization of an AIRE mutation in a consanguineous Chinese family with APS-1. All exons of the AIRE gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced. We identified a homozygous missense AIRE mutation c.463G>A (p.Gly155Ser in two siblings with different clinical features of APS-1. In silico splice-site prediction and minigene analysis were carried out to study the potential pathological consequence. Minigene splicing analysis and subsequent cDNA sequencing revealed that the AIRE mutation potentially compromised the recognition of the splice donor of intron 3, causing alternative pre-mRNA splicing by intron 3 retention. Furthermore, the aberrant AIRE transcript was identified in a heterozygous carrier of the c.463G>A mutation. The aberrant intron 3-retaining transcript generated a truncated protein (p.G155fsX203 containing the first 154 AIRE amino acids and followed by 48 aberrant amino acids. Therefore, our study represents the first functional characterization of the alternatively spliced AIRE mutation that may explain the pathogenetic role in APS-1.

  14. Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification

    Science.gov (United States)

    Hsu, Sandy Chan; Sears, Renee L.; Lemos, Roberta R.; Quintáns, Beatriz; Huang, Alden; Spiteri, Elizabeth; Nevarez, Lisette; Mamah, Catherine; Zatz, Mayana; Pierce, Kerrie D.; Fullerton, Janice M.; Adair, John C.; Berner, Jon E.; Bower, Matthew; Brodaty, Henry; Carmona, Olga; Dobricić, Valerija; Fogel, Brent L.; García-Estevez, Daniel; Goldman, Jill; Goudreau, John L.; Hopfer, Suellen; Janković, Milena; Jaumà, Serge; Jen, Joanna C.; Kirdlarp, Suppachok; Klepper, Joerg; Kostić, Vladimir; Lang, Anthony E.; Linglart, Agnès; Maisenbacher, Melissa K.; Manyam, Bala V.; Mazzoni, Pietro; Miedzybrodzka, Zofia; Mitarnun, Witoon; Mitchell, Philip B.; Mueller, Jennifer; Novaković, Ivana; Paucar, Martin; Paulson, Henry; Simpson, Sheila A.; Svenningsson, Per; Tuite, Paul; Vitek, Jerrold; Wetchaphanphesat, Suppachok; Williams, Charles; Yang, Michele; Schofield, Peter R.; de Oliveira, João R. M.; Sobrido, María-Jesús

    2014-01-01

    Familial idiopathic basal ganglia calcification (IBGC) or Fahr’s disease is a rare neurodegenerative disorder characterized by calcium deposits in the basal ganglia and other brain regions, which is associated with neuropsychiatric and motor symptoms. Familial IBGC is genetically heterogeneous and typically transmitted in an autosomal dominant fashion. We performed a mutational analysis of SLC20A2, the first gene found to cause IBGC, to assess its genetic contribution to familial IBGC. We recruited 218 subjects from 29 IBGC-affected families of varied ancestry and collected medical history, neurological exam, and head CT scans to characterize each patient’s disease status. We screened our patient cohort for mutations in SLC20A2. Twelve novel (nonsense, deletions, missense, and splice site) potentially pathogenic variants, one synonymous variant, and one previously reported mutation were identified in 13 families. Variants predicted to be deleterious cosegregated with disease in five families. Three families showed nonsegregation with clinical disease of such variants, but retrospective review of clinical and neuroimaging data strongly suggested previous misclassification. Overall, mutations in SLC20A2 account for as many as 41 % of our familial IBGC cases. Our screen in a large series expands the catalog of SLC20A2 mutations identified to date and demonstrates that mutations in SLC20A2 are a major cause of familial IBGC. Non-perfect segregation patterns of predicted deleterious variants highlight the challenges of phenotypic assessment in this condition with highly variable clinical presentation. PMID:23334463

  15. Presymptomatic generalized brain atrophy in frontotemporal dementia caused by CHMP2B mutation

    DEFF Research Database (Denmark)

    Rohrer, Jonathan D; Ahsan, R Laila; Isaacs, Adrian M;

    2009-01-01

    BACKGROUND/AIMS: CHMP2B mutations are a rare cause of familial frontotemporal dementia (FTD). The clinical syndrome is dominated by personality change and behavioural symptoms, but language, memory, calculation and praxis impairments are also seen early in the course of the disease. There are no ......BACKGROUND/AIMS: CHMP2B mutations are a rare cause of familial frontotemporal dementia (FTD). The clinical syndrome is dominated by personality change and behavioural symptoms, but language, memory, calculation and praxis impairments are also seen early in the course of the disease....... There are no detailed studies of brain imaging in CHMP2B mutation-associated FTD. This study aimed to investigate whether there were early or presymptomatic changes in this group of patients. METHODS: Subjects comprised 16 members of a Danish family with CHMP2B mutation-associated FTD. Nine subjects were presymptomatic...... mutation carriers with a control group of 7 mutation-negative family members. Volumetric MRI brain scans were performed on all subjects at two time points, and rates of volume change were compared between the two groups. RESULTS: We demonstrate that generalized atrophy occurs presymptomatically in CHMP2B...

  16. Identification of a Novel GJA8 (Cx50) Point Mutation Causes Human Dominant Congenital Cataracts

    Science.gov (United States)

    Ge, Xiang-Lian; Zhang, Yilan; Wu, Yaming; Lv, Jineng; Zhang, Wei; Jin, Zi-Bing; Qu, Jia; Gu, Feng

    2014-02-01

    Hereditary cataracts are clinically and genetically heterogeneous lens diseases that cause a significant proportion of visual impairment and blindness in children. Human cataracts have been linked with mutations in two genes, GJA3 and GJA8, respectively. To identify the causative mutation in a family with hereditary cataracts, family members were screened for mutations by PCR for both genes. Sequencing the coding regions of GJA8, coding for connexin 50, revealed a C > A transversion at nucleotide 264, which caused p.P88T mutation. To dissect the molecular consequences of this mutation, plasmids carrying wild-type and mutant mouse ORFs of Gja8 were generated and ectopically expressed in HEK293 cells and human lens epithelial cells, respectively. The recombinant proteins were assessed by confocal microscopy and Western blotting. The results demonstrate that the molecular consequences of the p.P88T mutation in GJA8 include changes in connexin 50 protein localization patterns, accumulation of mutant protein, and increased cell growth.

  17. Loss of function mutation in LOX causes thoracic aortic aneurysm and dissection in humans.

    Science.gov (United States)

    Lee, Vivian S; Halabi, Carmen M; Hoffman, Erin P; Carmichael, Nikkola; Leshchiner, Ignaty; Lian, Christine G; Bierhals, Andrew J; Vuzman, Dana; Mecham, Robert P; Frank, Natasha Y; Stitziel, Nathan O

    2016-08-01

    Thoracic aortic aneurysms and dissections (TAAD) represent a substantial cause of morbidity and mortality worldwide. Many individuals presenting with an inherited form of TAAD do not have causal mutations in the set of genes known to underlie disease. Using whole-genome sequencing in two first cousins with TAAD, we identified a missense mutation in the lysyl oxidase (LOX) gene (c.893T > G encoding p.Met298Arg) that cosegregated with disease in the family. Using clustered regularly interspaced short palindromic repeats (CRISPR)/clustered regularly interspaced short palindromic repeats-associated protein-9 nuclease (Cas9) genome engineering tools, we introduced the human mutation into the homologous position in the mouse genome, creating mice that were heterozygous and homozygous for the human allele. Mutant mice that were heterozygous for the human allele displayed disorganized ultrastructural properties of the aortic wall characterized by fragmented elastic lamellae, whereas mice homozygous for the human allele died shortly after parturition from ascending aortic aneurysm and spontaneous hemorrhage. These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall. Mutation carriers may be predisposed to vascular diseases because of weakened vessel walls under stress conditions. LOX sequencing for clinical TAAD may identify additional mutation carriers in the future. Additional studies using our mouse model of LOX-associated TAAD have the potential to clarify the mechanism of disease and identify novel therapeutics specific to this genetic cause.

  18. Sporadic cardiac and skeletal myopathy caused by a de novo desmin mutation.

    Science.gov (United States)

    Park, K Y; Dalakas, M C; Semino-Mora, C; Lee, H S; Litvak, S; Takeda, K; Ferrans, V J; Goldfarb, L G

    2000-06-01

    Desmin myopathy is a familial or sporadic disorder characterized by intracytoplasmic accumulation of desmin in the muscle cells. We and others have previously identified desmin gene mutations in patients with familial myopathy, but close to 45% of the patients do not report previous family history of the disease. The present study was conducted to determine the cause of desmin myopathy in a sporadic patient presenting with symmetrical muscle weakness and atrophy combined with atrioventricular conduction block requiring a permanent pacemaker. A novel heterozygous R406W mutation in the desmin gene was identified by sequencing cDNA and genomic DNA. Expression of a construct containing the patient's mutant desmin cDNA in SW13 (vim-) cells demonstrated a high pathogenic potential of the R406W mutation. This mutation was not found in the patient's father, mother or sister by sequencing and restriction analysis. Testing with five microsatellite markers and four intragenic single nucleotide polymorphisms excluded alternative paternity. Haplotype analysis indicates that the patient's father was germ-line mosaic for the desmin mutation. We conclude that de novo mutations in the desmin gene may be the cause of sporadic forms of desmin-related cardiac and skeletal myopathy.

  19. Myocilin Mutations Are Not a Major Cause of Primary Congenital Glaucoma in Iranian Patients

    Directory of Open Access Journals (Sweden)

    Elahe Elahi

    2010-01-01

    Full Text Available Purpose: To assess the frequency of mutations in the Myocilin (MYOC gene in Iranian patients affected with primary congenital glaucoma (PCG. Methods: The individuals evaluated herein are among a larger cohort of 100 patients who had previously been screened for CYP1B1 mutations. Eighty subjects carried mutations in CYP1B1, but the remaining 20 patients who did not, underwent screening for MYOC mutations for the purpose of the study. MYOC exons in the DNA were polymerase chain reaction (PCR amplified and sequenced. Sequencing was performed using PCR primers, the ABI big dye chemistry and an ABI3730XL instrument. Sequences were analyzed by comparing them to reference MYOC sequences using the Sequencher software. Results: Four MYOC sequence variations were observed among the patients, but none of them were considered to be associated with disease status. Three of these variations were single nucleotide polymorphisms already reported not to be disease causing, the fourth variation created a synonymous codon and did not affect any amino acid change. Conclusion: In this cohort, MYOC mutations were not observed in any Iranian subject with PCG. It is possible that in a larger sample, a few subjects carrying disease causing MYOC mutations could have been observed. But our results show that the contribution of MYOC to PCG status in Iran is small if any.

  20. A single origin for the most frequent mutation causing late infantile metachromatic leucodystrophy.

    Science.gov (United States)

    Zlotogora, J; Furman-Shaharabani, Y; Harris, A; Barth, M L; von Figura, K; Gieselmann, V

    1994-09-01

    Metachromatic leucodystrophy is an autosomal recessive degenerative disease of the nervous system caused by the deficiency of the lysosomal enzyme arylsulphatase A (ARSA). We report here on the high incidence of late infantile MLD among Muslim Arabs originating from Jerusalem, most probably because of a founder effect. All the patients were found to be homozygous for 459 + 1 G-->A, a mutation which destroys the splice donor site of exon 2 of the ARSA gene. This mutation has been reported to be the most common mutation causing MLD. We studied the ARSA haplotype defined by three intragenic polymorphic sites in DNA samples from Muslim Arab patients from Jerusalem, a Christian Arab patient originating from the region, and eight other white patients, all homozygous for the 459 + 1 G-->A mutation. All the alleles carried the same haplotype which is in complete linkage disequilibrium with the mutation. This finding indicates a common origin for the 459 + 1 G-->A mutation which may have been introduced into Jerusalem at the time of the Crusades.

  1. Gain-of-function SOS1 mutations cause a distinctive form of noonansyndrome

    Energy Technology Data Exchange (ETDEWEB)

    Tartaglia, Marco; Pennacchio, Len A.; Zhao, Chen; Yadav, KamleshK.; Fodale, Valentina; Sarkozy, Anna; Pandit, Bhaswati; Oishi, Kimihiko; Martinelli, Simone; Schackwitz, Wendy; Ustaszewska, Anna; Martin, Joes; Bristow, James; Carta, Claudio; Lepri, Francesca; Neri, Cinzia; Vasta,Isabella; Gibson, Kate; Curry, Cynthia J.; Lopez Siguero, Juan Pedro; Digilio, Maria Cristina; Zampino, Giuseppe; Dallapiccola, Bruno; Bar-Sagi, Dafna; Gelb, Brude D.

    2006-09-01

    Noonan syndrome (NS) is a developmental disordercharacterized by short stature, facial dysmorphia, congenital heartdefects and skeletal anomalies1. Increased RAS-mitogenactivated proteinkinase (MAPK) signaling due to PTPN11 and KRAS mutations cause 50 percentof NS2-6. Here, we report that 22 of 129 NS patients without PTPN11 orKRAS mutation (17 percent) have missense mutations in SOS1, which encodesa RAS-specific guanine nucleotide exchange factor (GEF). SOS1 mutationscluster at residues implicated in the maintenance of SOS1 in itsautoinhibited form and ectopic expression of two NS-associated mutantsinduced enhanced RAS activation. The phenotype associated with SOS1defects is distinctive, although within NS spectrum, with a highprevalence of ectodermal abnormalities but generally normal developmentand linear growth. Our findings implicate for the first timegain-of-function mutations in a RAS GEF in inherited disease and define anew mechanism by which upregulation of the RAS pathway can profoundlychange human development.

  2. Disease-causing mutations in the XIAP BIR2 domain impair NOD2-dependent immune signalling

    DEFF Research Database (Denmark)

    Damgaard, Rune Busk; Fiil, Berthe Katrine; Speckmann, Carsten;

    2013-01-01

    X-linked Inhibitor of Apoptosis (XIAP) is an essential ubiquitin ligase for pro-inflammatory signalling downstream of the nucleotide-binding oligomerization domain containing (NOD)-1 and -2 pattern recognition receptors. Mutations in XIAP cause X-linked lymphoproliferative syndrome type-2 (XLP2......), an immunodeficiency associated with a potentially fatal deregulation of the immune system, whose aetiology is not well understood. Here, we identify the XIAP baculovirus IAP repeat (BIR)2 domain as a hotspot for missense mutations in XLP2. We demonstrate that XLP2-BIR2 mutations severely impair NOD1/2-dependent...... immune signalling in primary cells from XLP2 patients and in reconstituted XIAP-deficient cell lines. XLP2-BIR2 mutations abolish the XIAP-RIPK2 interaction resulting in impaired ubiquitylation of RIPK2 and recruitment of linear ubiquitin chain assembly complex (LUBAC) to the NOD2-complex. We show...

  3. A human CCT5 gene mutation causing distal neuropathy impairs hexadecamer assembly in an archaeal model.

    Science.gov (United States)

    Min, Wonki; Angileri, Francesca; Luo, Haibin; Lauria, Antonino; Shanmugasundaram, Maruda; Almerico, Anna Maria; Cappello, Francesco; de Macario, Everly Conway; Lednev, Igor K; Macario, Alberto J L; Robb, Frank T

    2014-10-27

    Chaperonins mediate protein folding in a cavity formed by multisubunit rings. The human CCT has eight non-identical subunits and the His147Arg mutation in one subunit, CCT5, causes neuropathy. Knowledge is scarce on the impact of this and other mutations upon the chaperone's structure and functions. To make progress, experimental models must be developed. We used an archaeal mutant homolog and demonstrated that the His147Arg mutant has impaired oligomeric assembly, ATPase activity, and defective protein homeostasis functions. These results establish for the first time that a human chaperonin gene defect can be reproduced and studied at the molecular level with an archaeal homolog. The major advantage of the system, consisting of rings with eight identical subunits, is that it amplifies the effects of a mutation as compared with the human counterpart, in which just one subunit per ring is defective. Therefore, the slight deficit of a non-lethal mutation can be detected and characterized.

  4. Semi-automated, reverse-hybridization detection of multiple mutations causing hereditary fructose intolerance.

    Science.gov (United States)

    Kriegshäuser, Gernot; Halsall, David; Rauscher, Bettina; Oberkanins, Christian

    2007-06-01

    Hereditary fructose intolerance (HFI) is a potentially fatal nutritional disease that is caused by mutations in the liver isoenzyme of fructoaldolase (aldolase B). Our aim was to evaluate a diagnostic assay capable of simultaneously analyzing three-point mutations and a small deletion in the aldolase B (ALDOB) gene. The test under investigation is based on multiplex DNA amplification and hybridization to membrane strips presenting a parallel array of allele-specific oligonucleotide probes. We used the novel reverse-hybridization (RH) protocol to analyze 54 individuals previously genotyped by direct sequencing. RH genotyping for ALDOB mutations Delta4E4, A149P, A174D, and N334K was in complete concordance with results obtained by DNA sequencing. The procedure is rapid (<6h) and may be automated to a large extent. The RH assay tested in this study represents an accurate and robust screening tool to identify common ALDOB mutations.

  5. A novel fibrinogen B beta chain frameshift mutation causes congenital afibrinogenaemia.

    Science.gov (United States)

    Zhang, Jian; Zhao, Xiaojuan; Wang, Zhaoyue; Yu, Ziqiang; Cao, Lijuan; Zhang, Wei; Bai, Xia; Ruan, Changgeng

    2013-07-01

    Congenital afibrinogenaemia is a rare autosomal recessive disorder caused by various mutations within the fibrinogen genes FGA, FGB and FGG. Ins/del mutations in FGB are extremely rare. We report a patient with afibrinogenaemia who suffered from umbilical cord bleeding and repeated bleeding episodes. His plasma fibrinogen levels could not be detected using the Clauss method and immunological methods. Molecular analyses revealed homozygosity in a novel four bases insertion in codon 40 of FGB exon 2 (g. 2833_2834 ins GTTT), which resulted in a truncated 50-residue polypeptide that contained 11 exceptional abnormal residues. In the transient expression experiments, mutant fibrinogen could be detected at higher level than wild-type fibrinogen in COS-7 cell lysates but not in culture media. These results suggest that the homozygous mutation in FGB could be responsible for congenital afibrinogenaemia in this patient. This frameshift mutation could impair fibrinogen assembly and secretion without influencing the protein synthesis.

  6. Nucleos(t)ide analogues causes HBV S gene mutations and carcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Meng-Lan Wang; Hong Tang

    2016-01-01

    BACKGROUND: The long-term use of nucleos(t)ide analogues causes drug resistance and mutations in the HBV reverse tran-scriptase (RT) region of the polymerase gene. The RT region overlaps the HBV surface gene (S gene) and therefore, the mutations in the RT region simultaneously modify S gene se-quence. Certain mutations in the RT region bring about trun-cated S proteins because the corresponding changed S gene en-codes a stop codon which results in the loss of a large portion of the C-terminal hydrophobic region of HBV surface protein. The rtA181T/sW172*, rtM204I/sW196* and rtV191I/sW182*are the most frequently reported drug-resistant mutations with C-terminal truncation, these mutations have oncogenic potential. DATA SOURCES: PubMed and Web of Science were searched using terms: “hepatitis B virus”, “HBV drug resistance muta-tion”, “HBV surface protein”, “HBV truncation”, “hepatocel-lular carcinoma”, “rtA181T/sW172*”, “rtM204I/sW196*”,“rtV191I/sW182*”, and relevant articles published in English in the past decades were reviewed. RESULTS: The rtA181T/sW172* and rtV191I/sW182* mu-tants occurred more frequently than the rtM204I/sW196* mu-tant both in chronic hepatitis B patients and the HBV-related hepatocellular carcinoma tissues. Although these mutations occur naturally, nucleos(t)ide analogues therapy is the main driving force. These mutations may exist alone or coexist with other HBV mutations. All these three mutants impair the vi-rion secretion and result in HBV surface protein retention and serum HBV DNA level reduction. These mutations possess potential carcinogenic properties. The three mutations are re-sistant to more than one nucleos(t)ide analogue and therefore, it is dififcult to treat the patients with the truncated mutations. CONCLUSIONS: Nucleos(t)ide analogues induce drug resis-tance and HBV S gene truncated mutations. These mutations have potential carcinogenesis.

  7. Clinical-genetic correlations in familial Alzheimer's disease caused by presenilin 1 mutations.

    Science.gov (United States)

    Gómez-Tortosa, Estrella; Barquero, Sagrario; Barón, Manuel; Gil-Neciga, Eulogio; Castellanos, Fernando; Zurdo, Martín; Manzano, Sagrario; Muñoz, David G; Jiménez-Huete, Adolfo; Rábano, Alberto; Sainz, M José; Guerrero, Rosa; Gobernado, Isabel; Pérez-Pérez, Julián; Jiménez-Escrig, Adriano

    2010-01-01

    We describe the clinical phenotype of nine kindred with presenile Alzheimer's disease (AD) caused by different presenilin 1 (PS1) point mutations, and compare them with reported families with mutations in the same codons. Mutations were in exon 4 (Phe105Val), exon 5 (Pro117Arg, Glu120Gly), exon 6 (His163Arg), exon 7 (Leu226Phe), exon 8 (Val261Leu, Val272Ala, Leu282Arg), and exon 12 (Ile439Ser). Three of these amino acid changes (Phe105Val, Glu120Gly, and Ile439Ser) had not been previously reported. Distinct clinical features, including age of onset, symptoms and signs associated with the cortical-type dementia and aggressiveness of the disease, characterized the different mutations and were quite homogeneous across family members. Age of onset fell within a consistent range: some mutations caused the disease in the thirties (P117R, L226F, V272A), other in the forties (E120G, H163R, V261L, L282R), and other in the fifties (F105V, I439S). Associated features also segregated with specific mutations: early epileptic activity (E120G), spastic paraparesis (V261L), subcortical dementia and parkinsonism (V272A), early language impairment, frontal signs, and myoclonus (L226F), and late myoclonus and seizures (H163R, L282R). Neurological deterioration was particularly aggressive in PS1 mutations with earlier age of onset such as P117R, L226F, and E120G. With few exceptions, a similar clinical phenotype was found in families reported to have either the same mutation or different amino acid changes in the same codons. This series points to a strong influence of the specific genetic defect in the development of the clinical phenotype.

  8. Structural and functional analyses of disease-causing missense mutations in Bloom syndrome protein.

    Science.gov (United States)

    Guo, Rong-Bing; Rigolet, Pascal; Ren, Hua; Zhang, Bo; Zhang, Xing-Dong; Dou, Shuo-Xing; Wang, Peng-Ye; Amor-Gueret, Mounira; Xi, Xu Guang

    2007-01-01

    Bloom syndrome (BS) is an autosomal recessive disorder characterized by genomic instability and the early development of many types of cancer. Missense mutations have been identified in the BLM gene (encoding a RecQ helicase) in affected individuals, but the molecular mechanism and the structural basis of the effects of these mutations remain to be elucidated. We analysed five disease-causing missense mutations that are localized in the BLM helicase core region: Q672R, I841T, C878R, G891E and C901Y. The disease-causing mutants had low ATPase and helicase activities but their ATP binding abilities were normal, except for Q672, whose ATP binding activity was lower than that of the intact BLM helicase. Mutants C878R, mapping near motif IV, and G891E and C901Y, mapping in motif IV, displayed severe DNA-binding defects. We used molecular modelling to analyse these mutations. Our work provides insights into the molecular basis of BLM pathology, and reveals structural elements implicated in coupling DNA binding to ATP hydrolysis and DNA unwinding. Our findings will help to explain the mechanism underlying BLM catalysis and interpreting new BLM causing mutations identified in the future.

  9. Myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK) is caused by heterozygous KCNC1 mutations.

    Science.gov (United States)

    Nascimento, Fábio A; Andrade, Danielle M

    2016-09-01

    Progressive myoclonus epilepsy (PME) is a distinct group of seizure disorders characterized by gradual neurological decline with ataxia, myoclonus and recurring seizures. There are several forms of PME, among which the most recently described is MEAK - myoclonus epilepsy and ataxia due to potassium channel mutation. This particular subtype is caused by a recurrent de novo heterozygous mutation (c.959G>A, p.Arg320His) in the KCNC1 gene, which maps to chromosome 11 and encodes for the Kv3.1 protein (a subunit of the Kv3 subfamily of voltage-gated potassium channels). Loss of Kv3 function disrupts the firing properties of fast-spiking neurons, affects neurotransmitter release and induces cell death. Specifically regarding Kv3.1 malfunctioning, the most affected neurons include inhibitory GABAergic interneurons and cerebellar neurons. Impairment of the former cells is believed to contribute to myoclonus and seizures, whereas dysfunction of the latter to ataxia and tremor. Phenotypically, MEAK patients generally have a normal early development. At the age of 6 to 14 years, they present with myoclonus, which tends to progressively worsen with time. Tonic-clonic seizures may or may not be present, and some patients develop mild cognitive impairment following seizure onset. Typical electroencephalographic features comprise generalized epileptiform discharges and, in some cases, photosensitivity. Brain imaging is either normal or shows cerebellar atrophy. The identification of MEAK has both expanded the phenotypic and genotypic spectra of PME and established an emerging role for de novo mutations in PME.

  10. Catalytic deficiency of human aldolase B in hereditary fructose intolerance caused by a common missense mutation.

    Science.gov (United States)

    Cross, N C; Tolan, D R; Cox, T M

    1988-06-17

    Hereditary fructose intolerance (HFI) is a human autosomal recessive disease caused by a deficiency of aldolase B that results in an inability to metabolize fructose and related sugars. We report here the first identification of a molecular lesion in the aldolase B gene of an affected individual whose defective protein has previously been characterized. The mutation is a G----C transversion in exon 5 that creates a new recognition site for the restriction enzyme Ahall and results in an amino acid substitution (Ala----Pro) at position 149 of the protein within a region critical for substrate binding. Utilizing this novel restriction site and the polymerase chain reaction, the patient was shown to be homozygous for the mutation. Three other HFI patients from pedigrees unrelated to this individual were found to have the same mutation: two were homozygous and one was heterozygous. We suggest that this genetic lesion is a prevailing cause of hereditary fructose intolerance.

  11. Wolfram gene (WFS1) mutation causes autosomal dominant congenital nuclear cataract in humans.

    Science.gov (United States)

    Berry, Vanita; Gregory-Evans, Cheryl; Emmett, Warren; Waseem, Naushin; Raby, Jacob; Prescott, DeQuincy; Moore, Anthony T; Bhattacharya, Shomi S

    2013-12-01

    Congenital cataracts are an important cause of bilateral visual impairment in infants. Through genome-wide linkage analysis in a four-generation family of Irish descent, the disease-associated gene causing autosomal-dominant congenital nuclear cataract was mapped to chromosome 4p16.1. The maximum logarithm of odds (LOD) score was 2.62 at a recombination fraction θ=0, obtained for marker D4S432 physically close to the Wolfram gene (WFS1). By sequencing the coding regions and intron-exon boundaries of WFS1, we identified a DNA substitution (c.1385A-to-G) in exon 8, causing a missense mutation at codon 462 (E462G) of the Wolframin protein. This is the first report of a mutation in this gene causing an isolated nuclear congenital cataract. These findings suggest that the membrane trafficking protein Wolframin may be important for supporting the developing lens.

  12. A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy

    NARCIS (Netherlands)

    van der Kooi, AJ; de Visser, M; van Meegen, M; Ginjaar, HB; van Essen, AJ; Jennekens, FGI; Jongen, PJH; Leschot, NJ; Bolhuis, PA

    1998-01-01

    Limb girdle muscular dystrophy is a heterogeneous group of disorders. One autosomal recessive subtype, LGMD2C, has been linked to chromosome 13, and is caused by gamma-sarcoglycan deficiency in muscle. This report describes a novel missense mutation identified in a large consanguineous Dutch family

  13. The spectrum of mutations in UBE3A causing Angelman syndrome

    NARCIS (Netherlands)

    P. Fang (Ping); E. Lev-Lehman (Efrat); T.-F. Tsai (Ting-Fen); N. Matsuura (Nobuo); S. Benton (Sabrina); J.S. Sutcliffe (James); S.L. Christian (Susan); T. Kubota (Takeo); D.J.J. Halley (Dicky); E.J. Meijers-Heijboer (Hanne); S. Langlois (Sylvie); J.M. Graham (John); J. Beuten (Joke); P.J. Willems (Patrick); A.M. Ledbetter (Andrew M.); L. Beaudet (Lucille)

    1999-01-01

    textabstractAngelman syndrome (AS) is characterized by mental retardation, absence of speech, seizures and motor dysfunction. AS is caused by maternal deletions for chromosome 15q11-q13, paternal uniparental disomy (UPD), imprinting defects or loss-of-function mutations in the UBE3A locus which

  14. Dominant collagen VI mutations are a common cause of Ullrich congenital muscular dystrophy

    NARCIS (Netherlands)

    Baker, NL; Morgelin, M; Peat, R; Goemans, N; North, KN; Bateman, JF; Lamande, [No Value

    2005-01-01

    Mutations in the three collagen VI genes COL6A1, COL6A2 and COL6A3 cause Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). UCMD, a severe disorder characterized by congenital muscle weakness, proximal joint contractures and marked distal joint hyperextensibility, has been considered

  15. Frontotemporal dementia caused by CHMP2B mutation is characterised by neuronal lysosomal storage pathology

    DEFF Research Database (Denmark)

    Clayton, Emma L.; Mizielinska, Sarah; Edgar, James R.;

    2015-01-01

    Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The a...

  16. Frontotemporal dementia caused by CHMP2B mutation is characterised by neuronal lysosomal storage pathology

    DEFF Research Database (Denmark)

    Clayton, Emma L.; Mizielinska, Sarah; Edgar, James R.

    2015-01-01

    Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The a...

  17. Features of 5'-splice-site efficiency derived from disease-causing mutations and comparative genomics

    DEFF Research Database (Denmark)

    Roca, Xavier; Olson, Andrew J; Rao, Atmakuri R

    2007-01-01

    Many human diseases, including Fanconi anemia, hemophilia B, neurofibromatosis, and phenylketonuria, can be caused by 5'-splice-site (5'ss) mutations that are not predicted to disrupt splicing, according to position weight matrices. By using comparative genomics, we identify pairwise dependencies...

  18. Loss of stability and hydrophobicity of presenilin 1 mutations causing Alzheimer's Disease

    DEFF Research Database (Denmark)

    Somavarapu, Arun Kumar; Kepp, Kasper Planeta

    2016-01-01

    Nearly 200 mutations in the gene coding for presenilin 1 (PSEN1) cause early-onset Alzheimer's Disease, yet the molecular mechanism remains obscure. As a meta-analysis, we compiled available clinical and biochemical data for PSEN1 variants and correlated these to chemical properties of the mutants...

  19. A novel ICK mutation causes ciliary disruption and lethal endocrine-cerebro-osteodysplasia syndrome

    NARCIS (Netherlands)

    Oud, M.M.; Bonnard, C.; Mans, D.A.; Altunoglu, U.; Tohari, S.; Ng, A.Y.; Eskin, A.; Lee, H.; Rupar, C.A.; Wagenaar, N.P. de; Wu, K.M.; Lahiry, P.; Pazour, G.J.; Nelson, S.F.; Hegele, R.A.; Roepman, R.; Kayserili, H.; Venkatesh, B.; Siu, V.M.; Reversade, B.; Arts, H.H.

    2016-01-01

    BACKGROUND: Endocrine-cerebro-osteodysplasia (ECO) syndrome [MIM:612651] caused by a recessive mutation (p.R272Q) in Intestinal cell kinase (ICK) shows significant clinical overlap with ciliary disorders. Similarities are strongest between ECO syndrome, the Majewski and Mohr-Majewski short-rib

  20. Dominant collagen VI mutations are a common cause of Ullrich congenital muscular dystrophy

    NARCIS (Netherlands)

    Baker, NL; Morgelin, M; Peat, R; Goemans, N; North, KN; Bateman, JF; Lamande, [No Value

    2005-01-01

    Mutations in the three collagen VI genes COL6A1, COL6A2 and COL6A3 cause Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD). UCMD, a severe disorder characterized by congenital muscle weakness, proximal joint contractures and marked distal joint hyperextensibility, has been considered

  1. MRPL44 mutations cause a slowly progressive multisystem disease with childhood-onset hypertrophic cardiomyopathy

    NARCIS (Netherlands)

    Distelmaier, F.; Haack, T.B.; Catarino, C.B.; Gallenmuller, C.; Rodenburg, R.J.T.; Strom, T.M.; Baertling, F.; Meitinger, T.; Mayatepek, E.; Prokisch, H.; Klopstock, T.

    2015-01-01

    Defects in mitochondrial translation may lead to combined respiratory chain deficiency and typically cause childhood-onset multisystem disease. Only recently, a homozygous missense mutation (c.467T > G, p.Leu156Arg) in MRPL44, encoding a protein of the large subunit of the mitochondrial ribosome,

  2. Mutations in KRT5 and KRT14 cause epidermolysis bullosa simplex in 75% of the patients

    NARCIS (Netherlands)

    Bolling, M. C.; Lemmink, H. H.; Jansen, G. H. L.; Jonkman, M. F.

    2011-01-01

    P>Background Epidermolysis bullosa simplex (EBS) is a mechanobullous genodermatosis that may be caused by mutations in the genes KRT5 and KRT14 encoding the basal epidermal keratins 5 (K5) and 14 (K14). Three main clinical subtypes of EBS exist, differing in onset, distribution and severity of skin

  3. A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy

    NARCIS (Netherlands)

    van der Kooi, AJ; de Visser, Marianne; van Meegen, M; Ginjaar, HB; van Essen, AJ; Jennekens, FGI; Jongen, PJH; Leschot, NJ; Bolhuis, PA

    Limb girdle muscular dystrophy is a heterogeneous group of disorders. One autosomal recessive subtype, LGMD2C, has been linked to chromosome 13, and is caused by gamma-sarcoglycan deficiency in muscle. This report describes a novel missense mutation identified in a large consanguineous Dutch family

  4. A novel ICK mutation causes ciliary disruption and lethal endocrine-cerebro-osteodysplasia syndrome

    NARCIS (Netherlands)

    Oud, M.M.; Bonnard, C.; Mans, D.A.; Altunoglu, U.; Tohari, S.; Ng, A.Y.; Eskin, A.; Lee, H.; Rupar, C.A.; Wagenaar, N.P. de; Wu, K.M.; Lahiry, P.; Pazour, G.J.; Nelson, S.F.; Hegele, R.A.; Roepman, R.; Kayserili, H.; Venkatesh, B.; Siu, V.M.; Reversade, B.; Arts, H.H.

    2016-01-01

    BACKGROUND: Endocrine-cerebro-osteodysplasia (ECO) syndrome [MIM:612651] caused by a recessive mutation (p.R272Q) in Intestinal cell kinase (ICK) shows significant clinical overlap with ciliary disorders. Similarities are strongest between ECO syndrome, the Majewski and Mohr-Majewski short-rib thora

  5. Congenital isolated adrenocorticotropin deficiency: an underestimated cause of neonatal death, explained by TPIT gene mutations.

    NARCIS (Netherlands)

    Vallette-Kasic, S.; Brue, T.; Pulichino, A.M.; Gueydan, M.; Barlier, A.; David, M.; Nicolino, M.; Malpuech, G.; Dechelotte, P.; Deal, C.; Vliet, G. van; Vroede, M.A. de; Riepe, F.G.; Partsch, C.J.; Sippell, W.G.; Berberoglu, M.; Atasay, B.; Zegher, F. de; Beckers, D.; Kyllo, J.; Donohoue, P.; Fassnacht, M.; Hahner, S.; Allolio, B.; Noordam, C.; Dunkel, L.; Hero, M.; Pigeon, B.; Weill, J.; Yigit, S.; Brauner, R.; Heinrich, J.J.; Cummings, E.; Riddell, C.; Enjalbert, A.; Drouin, J.

    2005-01-01

    Tpit is a T box transcription factor important for terminal differentiation of pituitary proopiomelanocortin-expressing cells. We demonstrated that human and mouse mutations of the TPIT gene cause a neonatal-onset form of congenital isolated ACTH deficiency (IAD). In the absence of glucocorticoid

  6. Mutations in the nebulin gene can cause severe congenital nemaline myopathy

    NARCIS (Netherlands)

    Wallgren-Pettersson, C; Donner, K; Sewry, C; Lammens, M; Bushby, K; Uzielli, MLG; Lapi, E; Odent, S; Akcoren, Z; Topaloglu, H; Pelin, K; Bijlsma, E.

    2002-01-01

    Previously, we reported results indicating that nebulin was the gene causing the typical form of autosomal recessive nemaline (rod) myopathy. Here we describe the identification of mutations in the nebulin gene in seven offspring of five families affected by the severe congenital form of nemaline

  7. Mutations in the nebulin gene can cause severe congenital nemaline myopathy.

    NARCIS (Netherlands)

    Wallgren-Pettersson, C.; Donner, K.; Sewry, C.A.; Bijlsma, E.; Lammens, M.M.Y.; Bushby, K.; Giovannucci Uzielli, M.L.; Lapi, E.; Odent, S.; Akcoren, Z.; Topaloglu, H.; Pelin, K.

    2002-01-01

    Previously, we reported results indicating that nebulin was the gene causing the typical form of autosomal recessive nemaline (rod) myopathy. Here we describe the identification of mutations in the nebulin gene in seven offspring of five families affected by the severe congenital form of nemaline

  8. TUBA1A mutation can cause a hydranencephaly-like severe form of cortical dysgenesis.

    Science.gov (United States)

    Yokoi, Setsuri; Ishihara, Naoko; Miya, Fuyuki; Tsutsumi, Makiko; Yanagihara, Itaru; Fujita, Naoko; Yamamoto, Hiroyuki; Kato, Mitsuhiro; Okamoto, Nobuhiko; Tsunoda, Tatsuhiko; Yamasaki, Mami; Kanemura, Yonehiro; Kosaki, Kenjiro; Kojima, Seiji; Saitoh, Shinji; Kurahashi, Hiroki; Natsume, Jun

    2015-10-23

    TUBA1A mutations cause a wide spectrum of lissencephaly and brain malformations. Here, we report two patients with severe cortical dysgeneses, one with an extremely thin cerebral parenchyma apparently looking like hydranencephaly and the other with lissencephaly accompanied by marked hydrocephalus, both harbouring novel de novo missense mutations of TUBA1A. To elucidate how the various TUBA1A mutations affect the severity of the phenotype, we examined the capacity of the mutant protein to incorporate into the endogenous microtubule network in transfected COS7 cells by measuring line density using line extraction in an immunofluorescence study. The mutants responsible for severe phenotypes were found to incorporate extensively into the network. To determine how each mutant alters the microtubule stability, we examined cold-induced microtubule depolymerisation in fibroblasts. The depolymerisation of patients' fibroblasts occurred earlier than that of control fibroblasts, suggesting that microtubules bearing mutated tubulins are unstable. Both mutations are predicted to participate in lateral interactions of microtubules. Our data suggest that the TUBA1A mutations disrupting lateral interactions have pronounced dominant-negative effects on microtubule dynamics that are associated with the severe end of the lissencephaly spectrum.

  9. Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta.

    Science.gov (United States)

    Seymen, Figen; Kim, Youn Jung; Lee, Ye Ji; Kang, Jenny; Kim, Tak-Heun; Choi, Hwajung; Koruyucu, Mine; Kasimoglu, Yelda; Tuna, Elif Bahar; Gencay, Koray; Shin, Teo Jeon; Hyun, Hong-Keun; Kim, Young-Jae; Lee, Sang-Hoon; Lee, Zang Hee; Zhang, Hong; Hu, Jan C-C; Simmer, James P; Cho, Eui-Sic; Kim, Jung-Wook

    2016-11-03

    Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis.

  10. PRRT2 mutation causes paroxysmal kinesigenic dyskinesia and hemiplegic migraine in monozygotic twins.

    Science.gov (United States)

    Castiglioni, Claudia; López, Isabel; Riant, Florence; Bertini, Enrico; Terracciano, Alessandra

    2013-05-01

    PRRT2 gene mutations have recently been identified as a causative gene of Paroxysmal kinesigenic dyskinesia (PKD), a rare movement disorder characterised by the occurrence of chorea, dystonia or athetosis triggered by sudden action. Some patients have additional intermittent neurologic disorders like infantile convulsions. The association with migraine has been rarely reported in this condition. Here we report the coexistence of PKD and hemiplegic migraine in twins harbouring a heterozygous mutation in PRRT2. Two monozygotic twins manifesting PKD together with repeated episodes of migraine with some severe attacks of hemiplegic migraine have been followed and treated for more than 10 years. Molecular genetic analysis disclosed the c.649_650insC, p.R217Pfs*8 heterozygous mutation in both twins. This mutation was segregating from the mother who likewise harboured the same mutation c.649dupC although she had never manifested PKD but complained of rare common migraine attacks in her past history. The association of PKD and hemiplegic migraine has been previously reported in one large family, associated to febrile convulsions and afebrile seizures in some individuals, but our report relates this association of symptoms to a mutation in PRRT2. The co-occurrence of both hemiplegic migraine and PKD in monozygotic twins expands the phenotypic spectrum of intermittent manifestations related to PRRT2 and perhaps suggests an additional causing gene for hemiplegic migraine. Copyright © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  11. Axial Spondylometaphyseal Dysplasia Is Caused by C21orf2 Mutations.

    Directory of Open Access Journals (Sweden)

    Zheng Wang

    Full Text Available Axial spondylometaphyseal dysplasia (axial SMD is an autosomal recessive disease characterized by dysplasia of axial skeleton and retinal dystrophy. We conducted whole exome sequencing and identified C21orf2 (chromosome 21 open reading frame 2 as a disease gene for axial SMD. C21orf2 mutations have been recently found to cause isolated retinal degeneration and Jeune syndrome. We found a total of five biallelic C21orf2 mutations in six families out of nine: three missense and two splicing mutations in patients with various ethnic backgrounds. The pathogenic effects of the splicing (splice-site and branch-point mutations were confirmed on RNA level, which showed complex patterns of abnormal splicing. C21orf2 mutations presented with a wide range of skeletal phenotypes, including cupped and flared anterior ends of ribs, lacy ilia and metaphyseal dysplasia of proximal femora. Analysis of patients without C21orf2 mutation indicated genetic heterogeneity of axial SMD. Functional data in chondrocyte suggest C21orf2 is implicated in cartilage differentiation. C21orf2 protein was localized to the connecting cilium of the cone and rod photoreceptors, confirming its significance in retinal function. Our study indicates that axial SMD is a member of a unique group of ciliopathy affecting skeleton and retina.

  12. Two novel mutations in the PPIB gene cause a rare pedigree of osteogenesis imperfecta type IX.

    Science.gov (United States)

    Jiang, Yu; Pan, Jingxin; Guo, Dongwei; Zhang, Wei; Xie, Jie; Fang, Zishui; Guo, Chunmiao; Fang, Qun; Jiang, Weiying; Guo, Yibin

    2017-06-01

    Osteogenesis imperfecta (OI) is a rare genetic skeletal disorder characterized by increased bone fragility and vulnerability to fractures. PPIB is identified as a candidate gene for OI-IX, here we detect two pathogenic mutations in PPIB and analyze the genotype-phenotype correlation in a Chinese family with OI. Next-generation sequencing (NGS) was used to screen the whole exome of the parents of proband. Screening of variation frequency, evolutionary conservation comparisons, pathogenicity evaluation, and protein structure prediction were conducted to assess the pathogenicity of the novel mutations. Sanger sequencing was used to confirm the candidate variants. RTQ-PCR was used to analyze the PPIB gene expression. All mutant genes screened out by NGS were excluded except PPIB. Two novel heterozygous PPIB mutations (father, c.25A>G; mother, c.509G>A) were identified in relation to osteogenesis imperfecta type IX. Both mutations were predicted to be pathogenic by bioinformatics analysis and RTQ-PCR analysis revealed downregulated PPIB expression in the two carriers. We report a rare pedigree with an autosomal recessive osteogenesis imperfecta type IX (OI-IX) caused by two novel PPIB mutations identified for the first time in China. The current study expands our knowledge of PPIB mutations and their associated phenotypes, and provides new information on the genetic defects associated with this disease for clinical diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. EPILEPSY CAUSED BY PCDH19 GENE MUTATION: A REVIEW OF LITERATURE AND THE AUTHORS’ OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    K. Yu. Mukhin

    2016-01-01

    Full Text Available Mutation in the PCDH19 gene was first described by L.M. Dibbens et al. in 2008. Mutations in this gene are associated with epilepsy and mental retardation limited to females. The clinical manifestations that are observed in some patients with PCDH19 mutation and Dravet syndrome that is caused by mutation in the SCN1A gene include the onset of febrile and afebrile seizures in infancy, serial seizures during fever, and regression in development after the onset of seizures. Due to the fact that the two diseases have common clinical signs, it is best to test for PCDH19 mutation in patients with the clinical picture of Dravet syndrome and a negative test for SCN1A. In general, the number of scientific papers devoted to analysis and recommendations for the choice of therapy in patients with rare genetic pathology is small now. We analyzed the specific features of clinical signs and therapy in our two observed female patients aged 4 and 11 years with verified PCDH19 mutation. Both patients were noted to have severe epilepsy with febrile convulsions with the development of status epilepticus and to be unresponsive to antiepileptic therapy. The use of different antiepileptic drugs (valproate, oxcarbazepine, phenobarbital, topiramate, levetiracetam at different combinations failed to control the course of epilepsy in the 4-year-old patient whereas the 11-year-old patient who took a combination of valproic acid and benzodiazepines achieved a positive effect.

  14. Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer

    Science.gov (United States)

    2015-09-01

    Award Number: W81XWH-12-1-0333 TITLE: Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer PRINCIPAL...Caused by UVB Light in Skin Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Monica Ransom, PhD Betty Diamond 5d. PROJECT NUMBER...cells, Skin Cancer 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON USAMRMC a

  15. Mutations in ROGDI Cause Kohlschütter-Tönz Syndrome.

    Science.gov (United States)

    Schossig, Anna; Wolf, Nicole I; Fischer, Christine; Fischer, Maria; Stocker, Gernot; Pabinger, Stephan; Dander, Andreas; Steiner, Bernhard; Tönz, Otmar; Kotzot, Dieter; Haberlandt, Edda; Amberger, Albert; Burwinkel, Barbara; Wimmer, Katharina; Fauth, Christine; Grond-Ginsbach, Caspar; Koch, Martin J; Deichmann, Annette; von Kalle, Christof; Bartram, Claus R; Kohlschütter, Alfried; Trajanoski, Zlatko; Zschocke, Johannes

    2012-04-06

    Kohlschütter-Tönz syndrome (KTS) is an autosomal-recessive disease characterized by the combination of epilepsy, psychomotor regression, and amelogenesis imperfecta. The molecular basis has not yet been elucidated. Here, we report that KTS is caused by mutations in ROGDI. Using a combination of autozygosity mapping and exome sequencing, we identified a homozygous frameshift deletion, c.229_230del (p.Leu77Alafs(∗)64), in ROGDI in two affected individuals from a consanguineous family. Molecular studies in two additional KTS-affected individuals from two unrelated Austrian and Swiss families revealed homozygosity for nonsense mutation c.286C>T (p.Gln96(∗)) and compound heterozygosity for the splice-site mutations c.531+5G>C and c.532-2A>T in ROGDI, respectively. The latter mutation was also found to be heterozygous in the mother of the Swiss affected individual in whom KTS was reported for the first time in 1974. ROGDI is highly expressed throughout the brain and other organs, but its function is largely unknown. Possible interactions with DISC1, a protein involved in diverse cytoskeletal functions, have been suggested. Our finding that ROGDI mutations cause KTS indicates that the protein product of this gene plays an important role in neuronal development as well as amelogenesis. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  16. Novel splice, missense, and nonsense mutations in the fumarylacetoacetase gene causing tyrosinemia type I

    Energy Technology Data Exchange (ETDEWEB)

    Rootwelt, H.; Kvittingen, E.A. [Univ. of Oslo (Norway); Berger, R. [Wilhelmina Kinderziekenhuis, Utrecht (Netherlands); Gray, G.; Kelly, D.A. [Children`s Hospital, Birmingham (United Kingdom); Coskun, T. [Hacettepe Univ., Ankara (Turkey)

    1994-10-01

    In six unrelated patients with hereditary tyrosinemia type 1 (HT1), three different disease-causing mutations were found by DNA sequencing. Two Pakistani patients, with acute and intermediate forms of HT1, were homozygous for a G{sup 192} {yields} T mutation in the last nucleotide of exon 2. This caused aberrant splicing with partial intron 2 retention and premature termination. Three Turkish patients with chronic and intermediate forms of HT1 were homozygous for an A{sup 698} {yields} T mutation substituting aspartic acid 233 with valine. A Norwegian patient with an intermediate clinical phenotype was heterozygous for G{sup 786} {yields} A, introducing a TGA stop codon for Trp262 (W262X). Site-directed mutagenesis and expression in a rabbit reticulocyte lysate system demonstrated that the nonsense and missense mutations abolished fumarylacetoacetase activity and gave reduced amounts of a truncated and a full-length protein, respectively. Simple tests were established to identify the three mutations by restriction digestion of PCR-amplified genomic DNA. Among 30 additional HT1 patients investigated, 2 were found to be homozygous and 1 heterozygous for G{sup 192} {yields} T. Two other patients were homozygous and one was heterozygous for W262X. 21 refs., 4 figs.

  17. Cole-Carpenter syndrome is caused by a heterozygous missense mutation in P4HB.

    Science.gov (United States)

    Rauch, Frank; Fahiminiya, Somayyeh; Majewski, Jacek; Carrot-Zhang, Jian; Boudko, Sergei; Glorieux, Francis; Mort, John S; Bächinger, Hans-Peter; Moffatt, Pierre

    2015-03-05

    Cole-Carpenter syndrome is a severe bone fragility disorder that is characterized by frequent fractures, craniosynostosis, ocular proptosis, hydrocephalus, and distinctive facial features. To identify the cause of Cole-Carpenter syndrome in the two individuals whose clinical results were presented in the original description of this disorder, we performed whole-exome sequencing of genomic DNA samples from both individuals. The two unrelated individuals had the same heterozygous missense mutation in exon 9 of P4HB (NM_000918.3: c.1178A>G [p.Tyr393Cys]), the gene that encodes protein disulfide isomerase (PDI). In one individual, the P4HB mutation had arisen de novo, whereas in the other the mutation was transmitted from the clinically unaffected father who was a mosaic carrier of the variant. The mutation was located in the C-terminal disulfide isomerase domain of PDI, sterically close to the enzymatic center, and affected disulfide isomerase activity in vitro. Skin fibroblasts showed signs of increased endoplasmic reticulum stress, but despite the reported importance of PDI for collagen type I production, the rate of collagen type I secretion appeared normal. In conclusion, Cole-Carpenter syndrome is caused by a specific de novo mutation in P4HB that impairs the disulfide isomerase activity of PDI.

  18. Tissue-specific expression of a splicing mutation in the IKBKAP gene causes familial dysautonomia.

    Science.gov (United States)

    Slaugenhaupt, S A; Blumenfeld, A; Gill, S P; Leyne, M; Mull, J; Cuajungco, M P; Liebert, C B; Chadwick, B; Idelson, M; Reznik, L; Robbins, C; Makalowska, I; Brownstein, M; Krappmann, D; Scheidereit, C; Maayan, C; Axelrod, F B; Gusella, J F

    2001-03-01

    Familial dysautonomia (FD; also known as "Riley-Day syndrome"), an Ashkenazi Jewish disorder, is the best known and most frequent of a group of congenital sensory neuropathies and is characterized by widespread sensory and variable autonomic dysfunction. Previously, we had mapped the FD gene, DYS, to a 0.5-cM region on chromosome 9q31 and had shown that the ethnic bias is due to a founder effect, with >99.5% of disease alleles sharing a common ancestral haplotype. To investigate the molecular basis of FD, we sequenced the minimal candidate region and cloned and characterized its five genes. One of these, IKBKAP, harbors two mutations that can cause FD. The major haplotype mutation is located in the donor splice site of intron 20. This mutation can result in skipping of exon 20 in the mRNA of patients with FD, although they continue to express varying levels of wild-type message in a tissue-specific manner. RNA isolated from lymphoblasts of patients is primarily wild-type, whereas only the deleted message is seen in RNA isolated from brain. The mutation associated with the minor haplotype in four patients is a missense (R696P) mutation in exon 19, which is predicted to disrupt a potential phosphorylation site. Our findings indicate that almost all cases of FD are caused by an unusual splice defect that displays tissue-specific expression; and they also provide the basis for rapid carrier screening in the Ashkenazi Jewish population.

  19. A new mutation site in the AIRE gene causes autoimmune polyendocrine syndrome type 1.

    Science.gov (United States)

    Zhu, Wufei; Hu, Zhen; Liao, Xiangyu; Chen, Xing; Huang, Wenrong; Zhong, Yu; Zeng, Zhaoyang

    2017-05-24

    Autoimmune polyendocrine syndrome type 1 (APS-1, OMIM 2403000) is a rare autosomal recessive disease that is caused by autoimmune regulator (AIRE). The main symptoms of APS-1 are chronic mucocutaneous candidiasis, autoimmune adrenocortical insufficiency (Addison's disease) and hypoparathyroidism. We collected APS-1 cases and analysed them. The AIRE genes of the patient and his family members were sequenced to identify whether the APS-1 patient had an AIRE mutation. We discovered a mutation site (c.206A>C) that had never before been reported in the AIRE gene located in exon 2 of the AIRE gene. This homogyzous mutation caused a substitution of the 69th amino acid of the AIRE protein from glutamine to proline (p.Q69P). A yeast two-hybrid assay, which was used to analyse the homodimerization properties of the mutant AIRE protein, showed that the mutant AIRE protein could not interact with the normal AIRE protein. Flow cytometry and RT-qPCR analyses indicated that the new mutation site could decrease the expression levels of the AIRE, glutamic acid decarboxylase 65 (GAD65) and tryptophan hydroxylase-1 (TPH1) proteins to affect central immune tolerance. In conclusion, our research has shown that the new mutation site (c.206A>C) may influence the homodimerization and expression levels and other aspects of the AIRE protein. It may also impact the expression levels of tissue-restricted antigens (TRAs), leading to a series of autoimmune diseases.

  20. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes.

    Science.gov (United States)

    Schubert, Julian; Siekierska, Aleksandra; Langlois, Mélanie; May, Patrick; Huneau, Clément; Becker, Felicitas; Muhle, Hiltrud; Suls, Arvid; Lemke, Johannes R; de Kovel, Carolien G F; Thiele, Holger; Konrad, Kathryn; Kawalia, Amit; Toliat, Mohammad R; Sander, Thomas; Rüschendorf, Franz; Caliebe, Almuth; Nagel, Inga; Kohl, Bernard; Kecskés, Angela; Jacmin, Maxime; Hardies, Katia; Weckhuysen, Sarah; Riesch, Erik; Dorn, Thomas; Brilstra, Eva H; Baulac, Stephanie; Møller, Rikke S; Hjalgrim, Helle; Koeleman, Bobby P C; Jurkat-Rott, Karin; Lehman-Horn, Frank; Roach, Jared C; Glusman, Gustavo; Hood, Leroy; Galas, David J; Martin, Benoit; de Witte, Peter A M; Biskup, Saskia; De Jonghe, Peter; Helbig, Ingo; Balling, Rudi; Nürnberg, Peter; Crawford, Alexander D; Esguerra, Camila V; Weber, Yvonne G; Lerche, Holger

    2014-12-01

    Febrile seizures affect 2-4% of all children and have a strong genetic component. Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding syntaxin-1B, that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations and a de novo microdeletion encompassing STX1B were then identified in 449 familial or sporadic cases. Video and local field potential analyses of zebrafish larvae with antisense knockdown of stx1b showed seizure-like behavior and epileptiform discharges that were highly sensitive to increased temperature. Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes.

  1. Mutations in ROGDI Cause Kohlschütter-Tönz Syndrome

    Science.gov (United States)

    Schossig, Anna; Wolf, Nicole I.; Fischer, Christine; Fischer, Maria; Stocker, Gernot; Pabinger, Stephan; Dander, Andreas; Steiner, Bernhard; Tönz, Otmar; Kotzot, Dieter; Haberlandt, Edda; Amberger, Albert; Burwinkel, Barbara; Wimmer, Katharina; Fauth, Christine; Grond-Ginsbach, Caspar; Koch, Martin J.; Deichmann, Annette; von Kalle, Christof; Bartram, Claus R.; Kohlschütter, Alfried; Trajanoski, Zlatko; Zschocke, Johannes

    2012-01-01

    Kohlschütter-Tönz syndrome (KTS) is an autosomal-recessive disease characterized by the combination of epilepsy, psychomotor regression, and amelogenesis imperfecta. The molecular basis has not yet been elucidated. Here, we report that KTS is caused by mutations in ROGDI. Using a combination of autozygosity mapping and exome sequencing, we identified a homozygous frameshift deletion, c.229_230del (p.Leu77Alafs∗64), in ROGDI in two affected individuals from a consanguineous family. Molecular studies in two additional KTS-affected individuals from two unrelated Austrian and Swiss families revealed homozygosity for nonsense mutation c.286C>T (p.Gln96∗) and compound heterozygosity for the splice-site mutations c.531+5G>C and c.532-2A>T in ROGDI, respectively. The latter mutation was also found to be heterozygous in the mother of the Swiss affected individual in whom KTS was reported for the first time in 1974. ROGDI is highly expressed throughout the brain and other organs, but its function is largely unknown. Possible interactions with DISC1, a protein involved in diverse cytoskeletal functions, have been suggested. Our finding that ROGDI mutations cause KTS indicates that the protein product of this gene plays an important role in neuronal development as well as amelogenesis. PMID:22424600

  2. Hereditary juvenile cobalamin deficiency caused by mutations in the intrinsic factor gene.

    Science.gov (United States)

    Tanner, Stephan M; Li, Zhongyuan; Perko, James D; Oner, Cihan; Cetin, Mualla; Altay, Cigdem; Yurtsever, Zekiye; David, Karen L; Faivre, Laurence; Ismail, Essam A; Gräsbeck, Ralph; de la Chapelle, Albert

    2005-03-15

    Hereditary juvenile megaloblastic anemia due to vitamin B12 (cobalamin) deficiency is caused by intestinal malabsorption of cobalamin. In Imerslund-Grasbeck syndrome (IGS), cobalamin absorption is completely abolished and not corrected by the administration of intrinsic factor (IF); if untreated, the disease is fatal. Biallelic mutations either in the cubilin (CUBN) or amnionless (AMN) gene cause IGS. In a series of families clinically diagnosed with likely IGS, at least six displayed no evidence of mutations in CUBN or AMN. A genome-wide search for linkage followed by mutational analysis of candidate genes was performed in five of these families. A region in chromosome 11 showed evidence of linkage in four families. The gastric IF (GIF) gene located in this region harbored homozygous nonsense and missense mutations in these four families and in three additional families. The disease in these cases therefore should be classified as hereditary IF deficiency. Clinically, these patients resembled those with typical IGS; radiocobalamin absorption tests had been inconclusive regarding the nature of the defect. In the diagnosis of juvenile cobalamin deficiency, mutational analysis of the CUBN, AMN, and GIF genes provides a molecular characterization of the underlying defect and may be the diagnostic method of choice.

  3. Mutation in the glutamate transporter EAAT1 causes episodic ataxia, hemiplegia, and seizures.

    Science.gov (United States)

    Jen, J C; Wan, J; Palos, T P; Howard, B D; Baloh, R W

    2005-08-23

    Transporters, ion pumps, and ion channels are membrane proteins that regulate selective permeability and maintain ionic gradients across cell membranes. Mutations in CACNA1A encoding a neuronal calcium channel and ATP1A2 encoding an ion pump cause episodic ataxia, hemiplegic migraine, and seizures. Mutant gene products of both CACNA1A and ATP1A2 may affect neurotransmission of glutamate, the most abundant excitatory amino acid neurotransmitter. We examined our patient population with episodic ataxia and hemiplegic migraine but with no mutation in either CACNA1A or ATP1A2. We looked for mutations in SLC1A3, which encodes the glutamate transporter excitatory amino acid transporter (EAAT) 1 that is important in removing glutamate from the synaptic cleft. A patient with episodic ataxia, seizures, migraine, and alternating hemiplegia has a heterozygous mutation in SLC1A3 that is not present in his asymptomatic parents and controls. Expression studies of the mutant EAAT1 showed decreased expression of the protein with a markedly reduced capacity for glutamate uptake. When coexpressed, the mutant EAAT1 decreased the activity of wild-type EAAT1 but not of two other transporters EAAT2 or EAAT3, suggesting that mutant EAAT1 specifically multimerizes with wild-type EAAT1 to exert its dominant negative effect. Our data show that a heterozygous mutation in EAAT1 can lead to decreased glutamate uptake, which can contribute to neuronal hyperexcitability to cause seizures, hemiplegia, and episodic ataxia.

  4. Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine

    Institute of Scientific and Technical Information of China (English)

    Jin-Yang He; Yu-Tong Zhu; Rui-Yi Yang; Li-Ling Feng; Xing-Bo Guo; Feng-Xue Zhang; Hong-Shan Chen

    2005-01-01

    AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism.METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudineresistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation.RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein.CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.

  5. De Novo GMNN Mutations Cause Autosomal-Dominant Primordial Dwarfism Associated with Meier-Gorlin Syndrome.

    Science.gov (United States)

    Burrage, Lindsay C; Charng, Wu-Lin; Eldomery, Mohammad K; Willer, Jason R; Davis, Erica E; Lugtenberg, Dorien; Zhu, Wenmiao; Leduc, Magalie S; Akdemir, Zeynep C; Azamian, Mahshid; Zapata, Gladys; Hernandez, Patricia P; Schoots, Jeroen; de Munnik, Sonja A; Roepman, Ronald; Pearring, Jillian N; Jhangiani, Shalini; Katsanis, Nicholas; Vissers, Lisenka E L M; Brunner, Han G; Beaudet, Arthur L; Rosenfeld, Jill A; Muzny, Donna M; Gibbs, Richard A; Eng, Christine M; Xia, Fan; Lalani, Seema R; Lupski, James R; Bongers, Ernie M H F; Yang, Yaping

    2015-12-03

    Meier-Gorlin syndrome (MGS) is a genetically heterogeneous primordial dwarfism syndrome known to be caused by biallelic loss-of-function mutations in one of five genes encoding pre-replication complex proteins: ORC1, ORC4, ORC6, CDT1, and CDC6. Mutations in these genes cause disruption of the origin of DNA replication initiation. To date, only an autosomal-recessive inheritance pattern has been described in individuals with this disorder, with a molecular etiology established in about three-fourths of cases. Here, we report three subjects with MGS and de novo heterozygous mutations in the 5' end of GMNN, encoding the DNA replication inhibitor geminin. We identified two truncating mutations in exon 2 (the 1(st) coding exon), c.16A>T (p.Lys6(∗)) and c.35_38delTCAA (p.Ile12Lysfs(∗)4), and one missense mutation, c.50A>G (p.Lys17Arg), affecting the second-to-last nucleotide of exon 2 and possibly RNA splicing. Geminin is present during the S, G2, and M phases of the cell cycle and is degraded during the metaphase-anaphase transition by the anaphase-promoting complex (APC), which recognizes the destruction box sequence near the 5' end of the geminin protein. All three GMNN mutations identified alter sites 5' to residue Met28 of the protein, which is located within the destruction box. We present data supporting a gain-of-function mechanism, in which the GMNN mutations result in proteins lacking the destruction box and hence increased protein stability and prolonged inhibition of replication leading to autosomal-dominant MGS.

  6. A Missense Mutation in KCTD17 Causes Autosomal Dominant Myoclonus-Dystonia

    Science.gov (United States)

    Mencacci, Niccolo E.; Rubio-Agusti, Ignacio; Zdebik, Anselm; Asmus, Friedrich; Ludtmann, Marthe H.R.; Ryten, Mina; Plagnol, Vincent; Hauser, Ann-Kathrin; Bandres-Ciga, Sara; Bettencourt, Conceição; Forabosco, Paola; Hughes, Deborah; Soutar, Marc M.P.; Peall, Kathryn; Morris, Huw R.; Trabzuni, Daniah; Tekman, Mehmet; Stanescu, Horia C.; Kleta, Robert; Carecchio, Miryam; Zorzi, Giovanna; Nardocci, Nardo; Garavaglia, Barbara; Lohmann, Ebba; Weissbach, Anne; Klein, Christine; Hardy, John; Pittman, Alan M.; Foltynie, Thomas; Abramov, Andrey Y.; Gasser, Thomas; Bhatia, Kailash P.; Wood, Nicholas W.

    2015-01-01

    Myoclonus-dystonia (M-D) is a rare movement disorder characterized by a combination of non-epileptic myoclonic jerks and dystonia. SGCE mutations represent a major cause for familial M-D being responsible for 30%–50% of cases. After excluding SGCE mutations, we identified through a combination of linkage analysis and whole-exome sequencing KCTD17 c.434 G>A p.(Arg145His) as the only segregating variant in a dominant British pedigree with seven subjects affected by M-D. A subsequent screening in a cohort of M-D cases without mutations in SGCE revealed the same KCTD17 variant in a German family. The clinical presentation of the KCTD17-mutated cases was distinct from the phenotype usually observed in M-D due to SGCE mutations. All cases initially presented with mild myoclonus affecting the upper limbs. Dystonia showed a progressive course, with increasing severity of symptoms and spreading from the cranio-cervical region to other sites. KCTD17 is abundantly expressed in all brain regions with the highest expression in the putamen. Weighted gene co-expression network analysis, based on mRNA expression profile of brain samples from neuropathologically healthy individuals, showed that KCTD17 is part of a putamen gene network, which is significantly enriched for dystonia genes. Functional annotation of the network showed an over-representation of genes involved in post-synaptic dopaminergic transmission. Functional studies in mutation bearing fibroblasts demonstrated abnormalities in endoplasmic reticulum-dependent calcium signaling. In conclusion, we demonstrate that the KCTD17 c.434 G>A p.(Arg145His) mutation causes autosomal dominant M-D. Further functional studies are warranted to further characterize the nature of KCTD17 contribution to the molecular pathogenesis of M-D. PMID:25983243

  7. A founder TMIE mutation is a frequent cause of hearing loss in southeastern Anatolia.

    Science.gov (United States)

    Sirmaci, A; Oztürkmen-Akay, H; Erbek, S; Incesulu, A; Duman, D; Taşir-Yilmaz, S; Ozdağ, H; Tekin, M

    2009-06-01

    Using Affymetrix 10K arrays, we searched for regions of homozygosity in 51 Turkish families including at least three members with either congenital or prelingual autosomal recessive non-syndromic sensorineural hearing loss (ARNSSNHL), and identified four families whose deafness mapped to the DFNB6 locus on 3p21 containing the TMIE gene. Mutation analysis revealed the p.R84W mutation in all four families. Screening of this mutation in 254 families with ARNSSNHL, without GJB2 mutations, revealed four additional affected families. A novel mutation was found in a non-complementary marriage between a deaf couple who were homozygous for p.R84W and p.W57X, respectively with two affected children who were compound heterozygotes. Six of the TMIE families originated from southeastern Anatolia, making p.R84W a common cause of hearing loss in that region with a relative frequency of 10.3% (95% CI is 2.5-18.1%). The overall prevalence of the p.R84W mutation in ARNSSNHL in Turkey is 2.4% (95% CI is 0.7-4.0%). Genotyping of single-nucleotide polymorphisms flanking the TMIE gene revealed a conserved haplotype, suggesting a single origin for p.R84W from a common ancestor 1250 years ago (95% CI is 650-2500 years). We conclude that p.R84W could be a common mutation in other Middle Eastern populations and should be included in mutation screening offered to individuals with ARNSSNHL.

  8. Exome Sequencing Reveals Mutations in AIRE as a Cause of Isolated Hypoparathyroidism.

    Science.gov (United States)

    Li, Dong; Streeten, Elizabeth A; Chan, Alice; Lwin, Wint; Tian, Lifeng; Pellegrino da Silva, Renata; Kim, Cecilia E; Anderson, Mark S; Hakonarson, Hakon; Levine, Michael A

    2017-05-01

    Most cases of autosomal recessive hypoparathyroidism (HYPO) are caused by loss-of-function mutations in GCM2 or PTH. The objective of this study was to identify the underlying genetic basis for isolated HYPO in a kindred in which 3 of 10 siblings were affected. We studied the parents and the three adult affected subjects, each of whom was diagnosed with HYPO in the first decade of life. We collected clinical and biochemical data and performed whole exome sequencing analysis on DNA from the three affected subjects after negative genetic testing for known causes of HYPO. Whole exome sequencing followed by Sanger sequencing revealed that all three affected subjects were compound heterozygous for two previously reported mutations, c.967_979delCTGTCCCCTCCGC:p.(L323SfsX51) and c.995+(3_5)delGAGinsTAT, in AIRE, which encodes the autoimmune regulator protein that is defective in autoimmune polyglandular syndrome type 1 (APS-1). Each parent carries one mutation, and all of the children of the patients are either heterozygous for one mutation or wild type. The affected sister developed premature ovarian failure, but the two affected brothers have no other features of APS-1 despite elevated serum levels of anti-interferon-α antibodies. Our findings indicate that biallelic mutations in AIRE can cause isolated HYPO as well as syndromic APS-1. The presence of antibodies to interferon-α provides a highly sensitive indicator for loss of AIRE function and represents a useful marker for isolated HYPO due to AIRE mutations.

  9. A new mutation of the fukutin gene causing late-onset limb girdle muscular dystrophy

    DEFF Research Database (Denmark)

    Riisager, Maria; Duno, M; Hansen, Flemming Juul;

    2013-01-01

    to aberrations of FKTN is rare, with only eight reported cases of limb girdle phenotype (LGMD2M). We describe the mildest affected patient outside Japan with genetically confirmed LGMD2M and onset of symptoms at age 14. She was brought to medical attention at age 12, not because of muscle weakness, but due...... to episodes of tachycardia caused by Wolff-Parkinson-White syndrome. On examination, she had rigid spine syndrome, a typical limb girdle dystrophy pattern of muscle weakness, cardiomyopathy, and serum CK levels >2000 IU/L (normal G; p.Y306C mutation in the FKTN gene was found. The case confirms FKTN mutations...

  10. Mutations in the DNA methyltransferase gene DNMT3A cause an overgrowth syndrome with intellectual disability

    DEFF Research Database (Denmark)

    Tatton-Brown, Katrina; Seal, Sheila; Ruark, Elise

    2014-01-01

    Overgrowth disorders are a heterogeneous group of conditions characterized by increased growth parameters and other variable clinical features such as intellectual disability and facial dysmorphism. To identify new causes of human overgrowth, we performed exome sequencing in ten proband...... and histone binding. Similar mutations were not present in 1,000 UK population controls (13/152 cases versus 0/1,000 controls; P ... methylation during embryogenesis and is commonly somatically mutated in acute myeloid leukemia. Thus, DNMT3A joins an emerging group of epigenetic DNA- and histone-modifying genes associated with both developmental growth disorders and hematological malignancies....

  11. Partial nephrogenic diabetes insipidus caused by a novel mutation in the AVPR2 gene

    DEFF Research Database (Denmark)

    Færch, Mia; Christensen, Jane H; Corydon, Thomas J

    2008-01-01

    and polyuria since infancy. Initial clinical testing confirmed a diagnosis of diabetes insipidus (DI). Urine osmolarity rose during fluid deprivation and after 20 microg of intranasal desmopressin [1-deamino-8-d-arginine-vasopressin (dDAVP)]. A similar DI phenotype was found in his brother. Methods The coding...... output. Discussion The affected members of this Belgian kindred have CNDI with partial resistance to AVP caused by a mutation in the AVPR2 gene that differs from any of the six mutations reported previously to produce this phenotype. Because the resistance to AVP is partial, this form of CNDI can...

  12. A novel GJA8 mutation (p.V44A causing autosomal dominant congenital cataract.

    Directory of Open Access Journals (Sweden)

    Yanan Zhu

    Full Text Available To examine the mechanism by which a novel connexin 50 (Cx50 mutation, Cx50 V44A, in a Chinese family causes suture-sparing autosomal dominant congenital nuclear cataracts.Family history and clinical data were recorded and direct gene sequencing was used to identify the disease-causing mutation. The Cx50 gene was cloned from a human lens cDNA library. Connexin protein distributions were assessed by fluorescence microscopy. Hemichannel functions were analyzed by dye uptake assay. Formation of functional channels was assessed by dye transfer experiments.Direct sequencing of the candidate GJA8 gene revealed a novel c.131T>C transition in exon 2, which cosegregated with the disease in the family and resulted in the substitution of a valine residue with alanine at codon 44 (p. V44A in the extracellular loop 1 of the Cx50 protein. Both Cx50 and Cx50V44A formed functional gap junctions, as shown by the neurobiotin transfer assay. However, unlike wild-type Cx50, Cx50V44A was unable to form open hemichannels in dye uptake experiments.This work identified a unique congenital cataract in the Chinese population, caused by the novel mutation Cx50V44A, and it showed that the V44A mutation specifically impairs the gating of the hemichannels but not the gap junction channels. The dysfunctional hemichannels resulted in the development of human congenital cataracts.

  13. New mutations of SCN4A cause a potassium-sensitive normokalemic periodic paralysis.

    Science.gov (United States)

    Vicart, S; Sternberg, D; Fournier, E; Ochsner, F; Laforet, P; Kuntzer, T; Eymard, B; Hainque, B; Fontaine, B

    2004-12-14

    Periodic paralysis is classified into hypokalemic (hypoPP) and hyperkalemic (hyperPP) periodic paralysis according to variations of blood potassium levels during attacks. To describe new mutations in the muscle sodium channel gene SCN4A that cause periodic paralysis. A thorough clinical, electrophysiologic, and molecular study was performed of four unrelated families who presented with periodic paralysis. The nine affected members had episodes of muscle weakness reminiscent of both hyperPP and hypoPP. A provocative test with potassium chloride was positive in two patients. However, repeated and carefully performed tests of blood potassium levels during attacks resulted in normal potassium levels. Remarkably, two patients experienced hypokalemic episodes of paralysis related to peculiar provocative factors (corticosteroids and thyrotoxicosis). Similarly to hyperPP, electromyography in nine patients revealed increased compound muscle action potentials after short exercise and a delayed decline during rest after long exercise as well as myotonic discharges in one patient. With use of molecular genetic analysis of the gene SCN4A, three new mutations were found affecting codon 675. They resulted in an amino acid substitution of a highly conserved arginine (R) to either a glycine (G), a glutamine (Q), or a tryptophan (W). Interestingly, hypoPP is caused by both mutations affecting nearby codons as well as the change of an arginine into another amino acid. A potassium-sensitive and normokalemic type of periodic paralysis caused by new SCN4A mutations at codon 675 is reported.

  14. Ribosomal mutations cause p53-mediated dark skin and pleiotropic effects.

    Science.gov (United States)

    McGowan, Kelly A; Li, Jun Z; Park, Christopher Y; Beaudry, Veronica; Tabor, Holly K; Sabnis, Amit J; Zhang, Weibin; Fuchs, Helmut; de Angelis, Martin Hrabé; Myers, Richard M; Attardi, Laura D; Barsh, Gregory S

    2008-08-01

    Mutations in genes encoding ribosomal proteins cause the Minute phenotype in Drosophila and mice, and Diamond-Blackfan syndrome in humans. Here we report two mouse dark skin (Dsk) loci caused by mutations in Rps19 (ribosomal protein S19) and Rps20 (ribosomal protein S20). We identify a common pathophysiologic program in which p53 stabilization stimulates Kit ligand expression, and, consequently, epidermal melanocytosis via a paracrine mechanism. Accumulation of p53 also causes reduced body size and erythrocyte count. These results provide a mechanistic explanation for the diverse collection of phenotypes that accompany reduced dosage of genes encoding ribosomal proteins, and have implications for understanding normal human variation and human disease.

  15. A Scandinavian case of skin fragility, alopecia and cardiomyopathy caused by DSP mutations.

    Science.gov (United States)

    Vahlquist, A; Virtanen, M; Hellström-Pigg, M; Dragomir, A; Ryberg, K; Wilson, N J; Östman--Smith, I; Lu, L; McGrath, J A; Smith, F J D

    2014-01-01

    Congenital skin fragility is a heterogeneous disorder with epidermolysis bullosa and various skin infections as the leading causes. However, even rare diseases must be considered in the differential diagnosis of neonatal skin blistering, including some genetic syndromes with extracutaneous involvement. One such syndrome is ectodermal dysplasia due to deficiency of desmoplakin, a desmosomal protein essential for cellular cohesion in both epithelia and cardiac tissues. Desmoplakin is encoded by the DSP gene, which is localized on chromosome 6p24. Both dominant and recessive mutations in this gene have been reported to cause skin fragility and keratinization defects. We report a child born with a fragile epidermis, alopecia, thick nails, and focal hyperkeratoses on the digits and knees. She was found to have a deficiency of desmoplakin caused by compound heterozygous DSP mutations. She has gradually developed signs of a left ventricular cardiomyopathy.

  16. De novo mutations in HCN1 cause early infantile epileptic encephalopathy

    DEFF Research Database (Denmark)

    Nava, Caroline; Dalle, Carine; Rastetter, Agnès

    2014-01-01

    Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels contribute to cationic Ih current in neurons and regulate the excitability of neuronal networks. Studies in rat models have shown that the Hcn1 gene has a key role in epilepsy, but clinical evidence implicating HCN1 mutations...... in human epilepsy is lacking. We carried out exome sequencing for parent-offspring trios with fever-sensitive, intractable epileptic encephalopathy, leading to the discovery of two de novo missense HCN1 mutations. Screening of follow-up cohorts comprising 157 cases in total identified 4 additional amino...... toward atypical absences, intellectual disability and autistic traits. These findings provide clear evidence that de novo HCN1 point mutations cause a recognizable early-onset epileptic encephalopathy in humans....

  17. Diseases caused by mutations in Nav1.5 interacting proteins.

    Science.gov (United States)

    Kyle, John W; Makielski, Jonathan C

    2014-12-01

    Sodium current in the heart flows principally through the pore protein NaV1.5, which is part of a complex of interacting proteins that serve both to target and localize the complex in the membrane, and to modulate function by such post-translational modifications as phosphorylation and nitrosylation. Multiple mutations in seven different NaV1.5 interacting proteins have been associated with dysfunctional sodium current and inherited cardiac diseases, including long QT syndrome, Brugada syndrome, atrial fibrillation, and cardiomyopathy, as well as sudden infant death syndrome (SIDS). Mutations in as yet unidentified interacting proteins may account for cardiac disease for which a genetic basis has not yet been established. Characterizing the mechanisms by which these mutations cause disease may give insight into etiologies and treatments of more common acquired cardiac disease, such as ischemia and heart failure.

  18. A Novel CRYBB2 Stopgain Mutation Causing Congenital Autosomal Dominant Cataract in a Chinese Family

    Science.gov (United States)

    Zhou, Yu; Zhai, Yaru; Huang, Lulin; Gong, Bo; Li, Jie; Hao, Fang; Wu, Zhengzheng

    2016-01-01

    Congenital cataract is the most common cause of the visual disability and blindness in childhood. This study aimed to identify gene mutations responsible for autosomal dominant congenital cataract (ADCC) in a Chinese family using next-generation sequencing technology. This family included eight unaffected and five affected individuals. After complete ophthalmic examinations, the blood samples of the proband and two available family members were collected. Then the whole exome sequencing was performed on the proband and Sanger sequencing was applied to validate the causal mutation in the two family members and control samples. After the whole exome sequencing data were filtered through a series of existing variation databases, a heterozygous mutation c.499Tcongenital cataract population and illustrated the important role of CRYBB2 in the genetics research of congenital cataract. PMID:28025620

  19. Partial deficiency of emerin caused by a splice site mutation in EMD.

    Science.gov (United States)

    Yuan, Junhui; Ando, Masahiro; Higuchi, Itsuro; Sakiyama, Yusuke; Matsuura, Eiji; Michizono, Kumiko; Watanabe, Osamu; Nagano, Shinjiro; Inamori, Yukie; Hashiguchi, Akihiro; Higuchi, Yujiro; Yoshimura, Akiko; Takashima, Hiroshi

    2014-01-01

    Emery-Dreifuss muscular dystrophy (EDMD) is caused by mutations in the EMD gene on the X chromosome, which codes for emerin, an inner nuclear membrane protein. Monoclonal antibodies against the N-terminus of emerin protein are used to screen for emerin deficiency in clinical practice. However, these tests may not accurately reflect the disease in some cases. We herein describe the identification of a splice site mutation in the EMD gene in a Japanese patient who suffered from complete atrioventricular conduction block, mild muscle weakness and joint contracture, and a persistently elevated serum creatine kinase level. We used multiple antibodies to confirm the presence of a novel truncating mutation in emerin without the transmembrane region and C-terminus in the skeletal muscle.

  20. Nephrocalcinosis (Enamel Renal Syndrome) Caused by Autosomal Recessive FAM20A Mutations

    Science.gov (United States)

    Jaureguiberry, Graciana; De la Dure-Molla, Muriel; Parry, David; Quentric, Mickael; Himmerkus, Nina; Koike, Toshiyasu; Poulter, James; Klootwijk, Enriko; Robinette, Steven L.; Howie, Alexander J.; Patel, Vaksha; Figueres, Marie-Lucile; Stanescu, Horia C.; Issler, Naomi; Nicholson, Jeremy K.; Bockenhauer, Detlef; Laing, Christopher; Walsh, Stephen B.; McCredie, David A.; Povey, Sue; Asselin, Audrey; Picard, Arnaud; Coulomb, Aurore; Medlar, Alan J.; Bailleul-Forestier, Isabelle; Verloes, Alain; Le Caignec, Cedric; Roussey, Gwenaelle; Guiol, Julien; Isidor, Bertrand; Logan, Clare; Shore, Roger; Johnson, Colin; Inglehearn, Christopher; Al-Bahlani, Suhaila; Schmittbuhl, Matthieu; Clauss, François; Huckert, Mathilde; Laugel, Virginie; Ginglinger, Emmanuelle; Pajarola, Sandra; Spartà, Giuseppina; Bartholdi, Deborah; Rauch, Anita; Addor, Marie-Claude; Yamaguti, Paulo M.; Safatle, Heloisa P.; Acevedo, Ana Carolina; Martelli-Júnior, Hercílio; dos Santos Netos, Pedro E.; Coletta, Ricardo D.; Gruessel, Sandra; Sandmann, Carolin; Ruehmann, Denise; Langman, Craig B.; Scheinman, Steven J.; Ozdemir-Ozenen, Didem; Hart, Thomas C.; Hart, P. Suzanne; Neugebauer, Ute; Schlatter, Eberhard; Houillier, Pascal; Gahl, William A.; Vikkula, Miikka; Bloch-Zupan, Agnès; Bleich, Markus; Kitagawa, Hiroshi; Unwin, Robert J.; Mighell, Alan; Berdal, Ariane; Kleta, Robert

    2013-01-01

    Background/Aims Calcium homeostasis requires regulated cellular and interstitial systems interacting to modulate the activity and movement of this ion. Disruption of these systems in the kidney results in nephrocalcinosis and nephrolithiasis, important medical problems whose pathogenesis is incompletely understood. Methods We investigated 25 patients from 16 families with unexplained nephrocalcinosis and characteristic dental defects (amelogenesis imperfecta, gingival hyperplasia, impaired tooth eruption). To identify the causative gene, we performed genome-wide linkage analysis, exome capture, next-generation sequencing, and Sanger sequencing. Results All patients had bi-allelic FAM20A mutations segregating with the disease; 20 different mutations were identified. Conclusions This au-tosomal recessive disorder, also known as enamel renal syndrome, of FAM20A causes nephrocalcinosis and amelogenesis imperfecta. We speculate that all individuals with biallelic FAM20A mutations will eventually show nephrocalcinosis. PMID:23434854

  1. A Novel Mutation in the EDAR Gene Causes Severe Autosomal Recessive Hypohidrotic Ectodermal Dysplasia

    DEFF Research Database (Denmark)

    Henningsen, Emil; Svendsen, Mathias Tiedemann; Lildballe, D. L.

    2014-01-01

    We report on a 2-year-old girl presenting with a severe form of hypohidrotic ectodermal dysplasia (HED). The patient presented with hypotrichosis, anodontia, hypohidrosis, frontal bossing, prominent lips and ears, dry, pale skin, and dermatitis. The patient had chronic rhinitis with malodorous na......-mediated NF-kB signalling. This complete loss-of-function mutation likely accounts for the severe clinical abnormalities in ectodermal structures in the described patient. (C) 2014 Wiley Periodicals, Inc....... nasal discharge. The girl was the second born child of first-cousin immigrants from Northern Iraq. A novel homozygous mutation (c.84delC) in the EDAR gene was identified. This mutation most likely causes a frameshift in the protein product (p.S29fs*74). This results in abolition of all ectodysplasin...

  2. A novel frameshift mutation in FGF14 causes an autosomal dominant episodic ataxia.

    Science.gov (United States)

    Choquet, Karine; La Piana, Roberta; Brais, Bernard

    2015-07-01

    Episodic ataxias (EAs) are a heterogeneous group of neurological disorders characterized by recurrent attacks of ataxia. Mutations in KCNA1 and CACNA1A account for the majority of EA cases worldwide. We recruited a two-generation family affected with EA of unknown subtype and performed whole-exome sequencing on two affected members. This revealed a novel heterozygous mutation c.211_212insA (p.I71NfsX27) leading to a premature stop codon in FGF14. Mutations in FGF14 are known to cause spinocerebellar ataxia type 27 (SCA27). Sanger sequencing confirmed segregation within the family. Our findings expand the phenotypic spectrum of SCA27 by underlining the possible episodic nature of this ataxia.

  3. Novel mutations in EVC cause aberrant splicing in Ellis-van Creveld syndrome.

    Science.gov (United States)

    Shi, Lisong; Luo, Chunyan; Ahmed, Mairaj K; Attaie, Ali B; Ye, Xiaoqian

    2016-04-01

    Ellis-van Creveld syndrome (EvC) is a rare autosomal recessive disorder characterized by disproportionate chondrodysplasia, postaxial polydactyly, nail dystrophy, dental abnormalities and in a proportion of patients, congenital cardiac malformations. Weyers acrofacial dysostosis (Weyers) is another dominantly inherited disorder allelic to EvC syndrome but with milder phenotypes. Both disorders can result from loss-of-function mutations in either EVC or EVC2 gene, and phenotypes associated with the two gene mutations are clinically indistinguishable. We present here a clinical and molecular analysis of a Chinese family manifested specific features of EvC syndrome. Sequencing of both EVC and EVC2 identified two novel heterozygous splice site mutations c.384+5G>C in intron 3 and c.1465-1G>A in intron 10 in EVC, which were inherited from mother and father, respectively. In vitro minigene expression assay, RT-PCR and sequencing analysis demonstrated that c.384+5G>C mutation abolished normal splice site and created a new cryptic acceptor site within exon 4, whereas c.1465-1G>A mutation affected consensus splice junction site and resulted in full exon 11 skipping. These two aberrant pre-mRNA splicing processes both produced in-frame abnormal transcripts that possibly led to abolishment of important functional domains. To our knowledge, this is the first report of EVC mutations that cause EvC syndrome in Chinese population. Our data revealed that EVC splice site mutations altered splicing pattern and helped elucidate the pathogenesis of EvC syndrome.

  4. A founder mutation in Anoctamin 5 is a major cause of limb-girdle muscular dystrophy.

    Science.gov (United States)

    Hicks, Debbie; Sarkozy, A; Muelas, N; Koehler, K; Huebner, A; Hudson, G; Chinnery, P F; Barresi, R; Eagle, M; Polvikoski, T; Bailey, G; Miller, J; Radunovic, A; Hughes, P J; Roberts, R; Krause, S; Walter, M C; Laval, S H; Straub, V; Lochmüller, H; Bushby, K

    2011-01-01

    The limb-girdle muscular dystrophies are a group of disorders with wide genetic and clinical heterogeneity. Recently, mutations in the ANO5 gene, which encodes a putative calcium-activated chloride channel belonging to the Anoctamin family of proteins, were identified in five families with one of two previously identified disorders, limb-girdle muscular dystrophy 2L and non-dysferlin Miyoshi muscular dystrophy. We screened a candidate group of 64 patients from 59 British and German kindreds and found the truncating mutation, c.191dupA in exon 5 of ANO5 in 20 patients, homozygously in 15 and in compound heterozygosity with other ANO5 variants in the rest. An intragenic single nucleotide polymorphism and an extragenic microsatellite marker are in linkage disequilibrium with the mutation, suggesting a founder effect in the Northern European population. We have further defined the clinical phenotype of ANO5-associated muscular dystrophy. Patients show adult onset proximal lower limb weakness with highly raised serum creatine kinase values (average 4500 IU/l) and frequent muscle atrophy and asymmetry of muscle involvement. Onset varies from the early 20 s to 50 s and the weakness is generally slowly progressive, with most patients remaining ambulant for several decades. Distal presentation is much less common but a milder degree of distal lower limb weakness is often observed. Upper limb strength is only mildly affected and cardiac and respiratory function is normal. Females appear less frequently affected. In the North of England population we have identified eight patients with ANO5 mutations, suggesting a minimum prevalence of 0.27/100,000, twice as common as dysferlinopathy. We suggest that mutations in ANO5 represent a relatively common cause of adult onset muscular dystrophy with high serum creatine kinase and that mutation screening, particularly of the common mutation c.191dupA, should be an early step in the diagnostic algorithm of adult limb-girdle muscular

  5. A missense mutation in Fgfr1 causes ear and skull defects in hush puppy mice.

    Science.gov (United States)

    Calvert, Jennifer A; Dedos, Skarlatos G; Hawker, Kelvin; Fleming, Michelle; Lewis, Morag A; Steel, Karen P

    2011-06-01

    The hush puppy mouse mutant has been shown previously to have skull and outer, middle, and inner ear defects, and an increase in hearing threshold. The fibroblast growth factor receptor 1 (Fgfr1) gene is located in the region of chromosome 8 containing the mutation. Sequencing of the gene in hush puppy heterozygotes revealed a missense mutation in the kinase domain of the protein (W691R). Homozygotes were found to die during development, at approximately embryonic day 8.5, and displayed a phenotype similar to null mutants. Reverse transcription PCR indicated a decrease in Fgfr1 transcript in heterozygotes and homozygotes. Generation of a construct containing the mutation allowed the function of the mutated receptor to be studied. Immunocytochemistry showed that the mutant receptor protein was present at the cell membrane, suggesting normal expression and trafficking. Measurements of changes in intracellular calcium concentration showed that the mutated receptor could not activate the IP(3) pathway, in contrast to the wild-type receptor, nor could it initiate activation of the Ras/MAP kinase pathway. Thus, the hush puppy mutation in fibroblast growth factor receptor 1 appears to cause a loss of receptor function. The mutant protein appears to have a dominant negative effect, which could be due to it dimerising with the wild-type protein and inhibiting its activity, thus further reducing the levels of functional protein. A dominant modifier, Mhspy, which reduces the effect of the hush puppy mutation on pinna and stapes development, has been mapped to the distal end of chromosome 7 and may show imprinting.

  6. ITGB6 loss-of-function mutations cause autosomal recessive amelogenesis imperfecta.

    Science.gov (United States)

    Wang, Shih-Kai; Choi, Murim; Richardson, Amelia S; Reid, Bryan M; Lin, Brent P; Wang, Susan J; Kim, Jung-Wook; Simmer, James P; Hu, Jan C-C

    2014-04-15

    Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell-ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three integrin beta 6 (ITGB6) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an ITGB6 transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an ITGB6 transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an ITGB6 transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of Nance-Horan Syndrome (NHS Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing ITGB6 mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell-matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects.

  7. Mutational hot spot in the DSPP gene causing dentinogenesis imperfecta type II.

    Science.gov (United States)

    Kim, Jung-Wook; Hu, Jan C-C; Lee, Jae-Il; Moon, Sung-Kwon; Kim, Young-Jae; Jang, Ki-Taeg; Lee, Sang-Hoon; Kim, Chong-Chul; Hahn, Se-Hyun; Simmer, James P

    2005-02-01

    The current system for the classification of hereditary defects of tooth dentin is based upon clinical and radiographic findings and consists of two types of dentin dysplasia (DD) and three types of dentinogenesis imperfecta (DGI). However, whether DGI type III should be considered a distinct phenotype or a variation of DGI type II is debatable. In the 30 years since the classification system was first proposed, significant advances have been made regarding the genetic etiologies of inherited dentin defects. DGI type II is recognized as an autosomal dominant disorder with almost complete penetrance and a low frequency of de novo mutations. We have identified a mutation (c.52G-->T, p.V18F) at the first nucleotide of exon 3 of the DSPP (dentin sialophosphoprotein) gene in a Korean family (de novo) and a Caucasian family. This mutation has previously been reported as causing DGI type II in a Chinese family. These findings suggest that this mutation site represents a mutational "hot spot" in the DSPP gene. The clinical and radiographic features of these two families include the classic phenotypes associated with both DGI type II and type III. Finding that a single mutation causes both phenotypic patterns strongly supports the conclusion that DGI type II and DGI type III are not separate diseases but rather the phenotypic variation of a single disease. We propose a modification of the current classification system such that the designation "hereditary opalescent dentin" or "DGI type II" should be used to describe both the DGI type II and type III phenotypes.

  8. The molecular basis of variable phenotypic severity among common missense mutations causing Rett syndrome.

    Science.gov (United States)

    Brown, Kyla; Selfridge, Jim; Lagger, Sabine; Connelly, John; De Sousa, Dina; Kerr, Alastair; Webb, Shaun; Guy, Jacky; Merusi, Cara; Koerner, Martha V; Bird, Adrian

    2016-02-01

    Rett syndrome is caused by mutations in the X-linked MECP2 gene, which encodes a chromosomal protein that binds to methylated DNA. Mouse models mirror the human disorder and therefore allow investigation of phenotypes at a molecular level. We describe an Mecp2 allelic series representing the three most common missense Rett syndrome (RTT) mutations, including first reports of Mecp2[R133C] and Mecp2[T158M] knock-in mice, in addition to Mecp2[R306C] mutant mice. Together these three alleles comprise ∼25% of all RTT mutations in humans, but they vary significantly in average severity. This spectrum is mimicked in the mouse models; R133C being least severe, T158M most severe and R306C of intermediate severity. Both R133C and T158M mutations cause compound phenotypes at the molecular level, combining compromised DNA binding with reduced stability, the destabilizing effect of T158M being more severe. Our findings contradict the hypothesis that the R133C mutation exclusively abolishes binding to hydroxymethylated DNA, as interactions with DNA containing methyl-CG, methyl-CA and hydroxymethyl-CA are all reduced in vivo. We find that MeCP2[T158M] is significantly less stable than MeCP2[R133C], which may account for the divergent clinical impact of the mutations. Overall, this allelic series recapitulates human RTT severity, reveals compound molecular aetiologies and provides a valuable resource in the search for personalized therapeutic interventions.

  9. Transient neonatal diabetes mellitus caused by a de novo ABCC8 gene mutation

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    Jung Hyun Kong

    2011-04-01

    Full Text Available Transient neonatal diabetes mellitus (TNDM is a rare form of diabetes mellitus that presents within the first 6 months of life with remission in infancy or early childhood. TNDM is mainly caused by anomalies in the imprinted region on chromosome 6q24; however, recently, mutations in the ABCC8 gene, which encodes sulfonylurea receptor 1 (SUR1, have also been implicated in TNDM. Herein, we present the case of a male child with TNDM whose mutational analysis revealed a heterozygous c.3547C&gt;T substitution in the ABCC8 gene, leading to an Arg1183Trp mutation in the SUR1 protein. The parents were clinically unaffected and did not show a mutation in the ABCC8 gene. This is the first case of a de novo ABCC8 gene mutation in a Korean patient with TNDM. The patient was initially treated with insulin and successfully switched to sulfonylurea therapy at 14 months of age. Remission of diabetes had occurred at the age of 16 months. Currently, the patient is 21 months old and is euglycemic without any insulin or oral hypoglycemic agents. His growth and physical development are normal, and there are no delays in achieving neurological and developmental milestones.

  10. The LRRK2 G2019S mutation as the cause of Parkinson's disease in Ashkenazi Jews.

    Science.gov (United States)

    Thaler, Avner; Ash, Elissa; Gan-Or, Ziv; Orr-Urtreger, Avi; Giladi, Nir

    2009-11-01

    Mutations in the leucine rich repeat kinase 2 gene (LRRK2) are recognized as the most common cause of genetic Parkinsonism to date. The G2019S mutation has been implicated as an important determinant of Parkinson's disease (PD) in both Ashkenazi Jewish and North African Arab populations with carrier frequency of 29.7% among familial and 6% in sporadic Ashkenazi Jewish PD cases. PD patients with the G2019S mutation display similar clinical characteristics to patients with sporadic PD. While the function of the LRRK2 protein has yet to be fully determined, its distribution coincides with brain areas most affected by PD. The G2019S mutation is believed to be responsible for up-regulation of LRRK2 kinase activity, which may ultimately play a role in neuronal loss. The utility of LRRK2 G2019S screening in family members of Ashkenazi PD patients is discussed. LRRK2 G2019S mutation carriers without PD may be an ideal population for the study of possible neuroprotective strategies as they become available, and for furthering the understanding of the pathogenesis and long-term clinical outcomes of the disease.

  11. Mutations in Dnaaf1 and Lrrc48 Cause Hydrocephalus, Laterality Defects, and Sinusitis in Mice

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    Seungshin Ha

    2016-08-01

    Full Text Available We have previously described a forward genetic screen in mice for abnormalities of brain development. Characterization of two hydrocephalus mutants by whole-exome sequencing after whole-genome SNP mapping revealed novel recessive mutations in Dnaaf1 and Lrrc48. Mouse mutants of these two genes have not been previously reported. The Dnaaf1 mutant carries a mutation at the splice donor site of exon 4, which results in abnormal transcripts. The Lrrc48 mutation is a missense mutation at a highly conserved leucine residue, which is also associated with a decrease in Lrrc48 transcription. Both Dnaaf1 and Lrrc48 belong to a leucine-rich repeat-containing protein family and are components of the ciliary axoneme. Their Chlamydomonas orthologs are known to be required for normal ciliary beat frequency or flagellar waveform, respectively. Some Dnaaf1 or Lrrc48 homozygote mutants displayed laterality defects, suggesting a motile cilia defect in the embryonic node. Mucus accumulation and neutrophil infiltration in the maxillary sinuses suggested sinusitis. Dnaaf1 mutants showed postnatal lethality, and none survived to weaning age. Lrrc48 mutants survive to adulthood, but had male infertility. ARL13B immunostaining showed the presence of motile cilia in the mutants, and the distal distribution of DNAH9 in the axoneme of upper airway motile cilia appeared normal. The phenotypic abnormalities suggest that mutations in Dnaaf1 and Lrrc48 cause defects in motile cilia function.

  12. Ankyrin-B mutation causes type 4 long-QT cardiac arrhythmia and sudden cardiac death.

    Science.gov (United States)

    Mohler, Peter J; Schott, Jean-Jacques; Gramolini, Anthony O; Dilly, Keith W; Guatimosim, Silvia; duBell, William H; Song, Long-Sheng; Haurogné, Karine; Kyndt, Florence; Ali, Mervat E; Rogers, Terry B; Lederer, W J; Escande, Denis; Le Marec, Herve; Bennett, Vann

    2003-02-06

    Mutations in ion channels involved in the generation and termination of action potentials constitute a family of molecular defects that underlie fatal cardiac arrhythmias in inherited long-QT syndrome. We report here that a loss-of-function (E1425G) mutation in ankyrin-B (also known as ankyrin 2), a member of a family of versatile membrane adapters, causes dominantly inherited type 4 long-QT cardiac arrhythmia in humans. Mice heterozygous for a null mutation in ankyrin-B are haploinsufficient and display arrhythmia similar to humans. Mutation of ankyrin-B results in disruption in the cellular organization of the sodium pump, the sodium/calcium exchanger, and inositol-1,4,5-trisphosphate receptors (all ankyrin-B-binding proteins), which reduces the targeting of these proteins to the transverse tubules as well as reducing overall protein level. Ankyrin-B mutation also leads to altered Ca2+ signalling in adult cardiomyocytes that results in extrasystoles, and provides a rationale for the arrhythmia. Thus, we identify a new mechanism for cardiac arrhythmia due to abnormal coordination of multiple functionally related ion channels and transporters.

  13. Identification and expression analysis of a novel intragenic EFNB1 mutation causing craniofrontonasal syndrome

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    Oscar F. Chacon-Camacho

    2014-12-01

    Full Text Available Craniofrontonasal syndrome (CFNS is an X-linked disorder caused by mutations in the EFNB1 gene and characterized by distinctive craniofacial and digital malformations. In contrast with most X-linked traits, female patients with CFNS display a more severe phenotype than males. In this report, the clinical, molecular and RNA expression analyses of a female subject with CFNS are described. A novel c.445_449delGAGGG deletion in exon 3 of EFNB1 was demonstrated in this patient. To assess the effect of this novel mutation at the transcript level, the expression of EFNB1 mRNA was studied by quantitative RT-PCR. To our knowledge, this is the first time that an EFNB1 transcript carrying a truncating mutation in exon 3 is demonstrated to undergo degradation by nonsense-mediated mRNA decay. Our results expand the mutational spectrum of CFNS and add to the functional consequences of truncating EFNB1 mutations.

  14. A novel fibrinogen mutation (γ Thr277Arg) causes hereditary hypofibrinogenemia in a Chinese family.

    Science.gov (United States)

    Zhu, Liqing; Wang, Mingshan; Xie, Haixiao; Jin, Yanhui; Yang, Lihong; Xu, Pengfei

    2013-09-01

    Congenital hypofibrinogenemia is a rare disorder caused by heterozygous mutations in one of the three fibrinogen genes--fibrinogen α-chain (FGA), fibrinogen β-chain (FGB) and fibrinogen γ-chain (FGG)--which code for the Aα, Bβ and γ chains, respectively. In this study, we identified a genetic defect in the FGG underlying the hypofibrinogenemia. The proposita had a prolonged blood clotting time (thrombin time 24.5 s, prothrombin time 16.8 s) and a low level of plasma fibrinogen (0.71 g/l by Clauss method and 0.79 g/l by immunoturbidimetry). DNA screening of the whole fibrinogen gene revealed a heterozygous GC mutation at nucleotide 7482 in her FGG gene. Her father and her half-brother are also heterozygous for this mutation. This mutation contributes to Thr277 → Arg in the γ chain of fibrinogen. To the best of our knowledge, this is the first report of such a mutation that is associated with hypofibrinogenemia.

  15. GATA6 mutations cause human cardiac outflow tract defects by disrupting semaphorin-plexin signaling

    Science.gov (United States)

    Kodo, Kazuki; Nishizawa, Tsutomu; Furutani, Michiko; Arai, Shoichi; Yamamura, Eiji; Joo, Kunitaka; Takahashi, Takao; Matsuoka, Rumiko; Yamagishi, Hiroyuki

    2009-01-01

    Congenital heart diseases (CHD) occur in nearly 1% of all live births and are the major cause of infant mortality and morbidity. Although an improved understanding of the genetic causes of CHD would provide insight into the underlying pathobiology, the genetic etiology of most CHD remains unknown. Here we show that mutations in the gene encoding the transcription factor GATA6 cause CHD characteristic of a severe form of cardiac outflow tract (OFT) defect, namely persistent truncus arteriosus (PTA). Two different GATA6 mutations were identified by systematic genetic analysis using DNA from patients with PTA. Genes encoding the neurovascular guiding molecule semaphorin 3C (SEMA3C) and its receptor plexin A2 (PLXNA2) appear to be regulated directly by GATA6, and both GATA6 mutant proteins failed to transactivate these genes. Transgenic analysis further suggests that, in the developing heart, the expression of SEMA3C in the OFT/subpulmonary myocardium and PLXNA2 in the cardiac neural crest contributing to the OFT is dependent on GATA transcription factors. Together, our data implicate mutations in GATA6 as genetic causes of CHD involving OFT development, as a result of the disruption of the direct regulation of semaphorin-plexin signaling. PMID:19666519

  16. Mutations in FKBP10 can cause a severe form of isolated Osteogenesis imperfecta

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    Steinlein Ortrud K

    2011-11-01

    Full Text Available Abstract Background Mutations in the FKBP10 gene were first described in patients with Osteogenesis imperfecta type III. Two follow up reports found FKBP10 mutations to be associated with Bruck syndrome type 1, a rare disorder characterized by congenital contractures and bone fragility. This raised the question if the patients in the first report indeed had isolated Osteogenesis imperfecta or if Bruck syndrome would have been the better diagnosis. Methods The patients described here are affected by severe autosomal recessive Osteogenesis imperfecta without contractures. Results Homozygosity mapping identified FKBP10 as a candidate gene, and sequencing revealed a base pair exchange that causes a C-terminal premature stop codon in this gene. Conclusions Our study demonstrates that FKBP10 mutations not only cause Bruck syndrome or Osteogenesis imperfecta type III but can result in a severe type of isolated Osteogenesis imperfecta type IV with prenatal onset. Furthermore, it adds dentinogenesis imperfecta to the spectrum of clinical symptoms associated with FKBP10 mutations.

  17. A novel DSPP mutation causes dentinogenesis imperfecta type II in a large Mongolian family

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    Chen Yujie

    2010-02-01

    Full Text Available Abstract Background Several studies have shown that the clinical phenotypes of dentinogenesis imperfecta type II (DGI-II may be caused by mutations in dentin sialophosphoprotein (DSPP. However, no previous studies have documented the clinical phenotype and genetic basis of DGI-II in a Mongolian family from China. Methods We identified a large five-generation Mongolian family from China with DGI-II, comprising 64 living family members of whom 22 were affected. Linkage analysis of five polymorphic markers flanking DSPP gene was used to genotype the families and to construct the haplotypes of these families. All five DSPP exons including the intron-exon boundaries were PCR-amplified and sequenced in 48 members of this large family. Results All affected individuals showed discoloration and severe attrition of their teeth, with obliterated pulp chambers and without progressive high frequency hearing loss or skeletal abnormalities. No recombination was found at five polymorphic markers flanking DSPP in the family. Direct DNA sequencing identified a novel A→G transition mutation adjacent to the donor splicing site within intron 3 in all affected individuals but not in the unaffected family members and 50 unrelated Mongolian individuals. Conclusion This study identified a novel mutation (IVS3+3A→G in DSPP, which caused DGI-II in a large Mongolian family. This expands the spectrum of mutations leading to DGI-II.

  18. Mutation in the CYP21B gene (Ile-172. -->. Asn) causes steroid 21-hydroxylase deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Amor, M.; Parker, K.L.; Globerman, H.; New, M.I.; White, P.C.

    1988-03-01

    Steroid 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia. It results from a deficiency in a specific cytochrome P450, P450c21 (P450XXIA). The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) are located in the HLA complex on chromosome 6p. Many mutant alleles are associated with deletions of CYP21B; the authors report the cloning and characterization of a nondeleted mutant CYP21B gene. This mutant gene is expressed on transfection into mouse Y1 adrenal cells, producing mRNA levels similar to those seen after transfection of the normal CYP21B gene. In codon 172 of the mutant gene, the normal codon ATC, encoding isoleucine, has been changed to AAC, encoding asparagine. This mutation is normally present in the CYP21A pseudogene, so that it may have been transferred to the mutant CYP21B gene by gene conversion. Hybridization of oligonucleotide probes corresponding to this and two other mutations normally present in CYP21A demonstrated that 4 out of 20 patients carried the codon 172 mutation; in one of these patients, the mutation was present as part of a larger gene conversion involving at least exons 3-6. Gene conversion may be a frequent cause of 21-hydroxylase deficiency.

  19. Marfan syndrome caused by a novel FBN1 mutation with associated pigmentary glaucoma.

    Science.gov (United States)

    Kuchtey, John; Chang, Ta Chen; Panagis, Lampros; Kuchtey, Rachel W

    2013-04-01

    Mutations in fibrillin-1 (FBN1) cause a wide spectrum of disorders, including Marfan syndrome, which have in common defects in fibrillin-1 microfibrils. Ectopia lentis and myopia are frequently observed ocular manifestations of Marfan syndrome. Glaucoma is also associated with Marfan syndrome, though the form of glaucoma has not been well-characterized. In this report, ocular examination of a patient diagnosed with Marfan syndrome based on family history and aortic dilatation was performed, including measurement of facility of aqueous humor outflow by tonography. The patient did not have ectopia lentis at the age of 42 years. Based on optic nerve appearance, reduced outflow facility, elevated IOP with open angles and clear signs of pigment dispersion, the patient was diagnosed with pigmentary glaucoma. The patient was heterozygous for a novel truncating mutation in FBN1, p.Leu72Ter. Histology of normal human eyes revealed abundant expression of elastic fibers and fibrillin-1 in aqueous humor outflow structures. This is the first report of a patient with Marfan syndrome that is caused by a confirmed FBN1 mutation with associated pigmentary glaucoma. In addition to identifying a novel mutation of FBN1 and broadening the spectrum of associated ocular phenotypes in Marfan syndrome, our findings suggest that pigmentary glaucoma may involve defects in fibrillin-1 microfibrils.

  20. WDR73 missense mutation causes infantile onset intellectual disability and cerebellar hypoplasia in a consanguineous family.

    Science.gov (United States)

    Jiang, Chen; Gai, Nan; Zou, Yongyi; Zheng, Yu; Ma, Ruiyu; Wei, Xianda; Liang, Desheng; Wu, Lingqian

    2017-01-01

    Galloway-Mowat syndrome (GMS) is a very rare autosomal-recessive disorder characterized by nephrotic syndrome associated with microcephaly, and various central nervous system abnormalities, mostly cerebral hypoplasia or cerebellar atrophy, intellectual disability and neural-migration defects. WDR73 is the only gene known to cause GMS, and has never been implicated in other disease. Here we present a Chinese consanguineous family with infantile onset intellectual disability and cerebellar hypoplasia but no microcephaly. Whole exome sequencing identified a WDR73 p.W371G missense mutation. The mutation is confirmed to be segregated in this family by Sanger sequencing according to a recessive inheritance pattern. It is predicted to be deleterious by multiple algorithms and affect highly conserved site. Structural modeling revealed conformational differences between the wild type protein and the p.W371G protein. Real-time PCR and Western blotting revealed altered mRNA and protein levels in mutated samples. Our study indicates the novel WDR73 p.W371G missense mutation causes infantile onset intellectual disability and cerebellar hypoplasia in recessive mode of inheritance. Our findings imply that microcephaly is a variable phenotype in WDR73-related disease, suggest WDR73 to be a candidate gene of severe intellectual disability and cerebellar hypoplasia, and expand the molecular spectrum of WDR73-related disease.

  1. Capturing all disease-causing mutations for clinical and research use : Toward an effortless system for the Human Variome Project

    NARCIS (Netherlands)

    Cotton, Richard G. H.; Al Aqeel, Aida I.; Al-Mulla, Fahd; Carrera, Paola; Claustres, Mireille; Ekong, Rosemary; Hyland, Valentine J.; Macrae, Finlay A.; Marafie, Makia J.; Paalman, Mark H.; Patrinos, George P.; Qi, Ming; Ramesar, Rajkumar S.; Scott, Rodney J.; Sijmons, Rolf H.; Sobrido, Maria-Jesus; Vihinen, Mauno

    2009-01-01

    The collection of genetic variants that cause inherited disease (causative mutation) has occurred for decades albeit in an ad hoc way, for research and clinical purposes. More recently, the access to collections of mutations causing specific diseases has become essential for appropriate genetic heal

  2. [Hereditary cardiomyopathies: a review. Mutation of structural proteins a common cause of hereditary cardiomyopathy].

    Science.gov (United States)

    Sjöberg, Gunnar; Kostareva, Anna; Sejersen, Thomas

    Cardiomyopathy is a disorder of the cardiac muscle and can be either primary or secondary. The primary disorders have been classified by WHO into 4 groups based on structure and function; hypertrophic, dilated and restricted cardiomyopathies and arrythmogenic right ventricle dysplasia. During the last decade the familial nature of many of these cardiomyopathies has been elucidated and different genes have been found to be mutated and causative of disease. Certain patterns can be distinguished in the mutated genes, e.g. in general the genes causing hypertrophic cardiomyopathies code for proteins involved in the contractile apparatus, the sarcomere, and the genes causing dilated cardiomyopathy code for proteins that anchor the sarcomere to the cell membrane and extracellular matrix. This article reviews these recent genetic findings and discusses their potential clinical applicability.

  3. A novel SERPINA1 mutation causing serum alpha(1-antitrypsin deficiency.

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    Darren N Saunders

    Full Text Available Mutations in the SERPINA1 gene can cause deficiency in the circulating serine protease inhibitor α(1-Antitrypsin (α(1AT. α(1AT deficiency is the major contributor to pulmonary emphysema and liver disease in persons of European ancestry, with a prevalence of 1 in 2500 in the USA. We present the discovery and characterization of a novel SERPINA1 mutant from an asymptomatic Middle Eastern male with circulating α(1AT deficiency. This 49 base pair deletion mutation (T379Δ, originally mistyped by IEF, causes a frame-shift replacement of the last sixteen α(1AT residues and adds an extra twenty-four residues. Functional analysis showed that the mutant protein is not secreted and prone to intracellular aggregation.

  4. Homozygosity for a novel truncating mutation confirms TBX15 deficiency as the cause of Cousin syndrome.

    Science.gov (United States)

    Dikoglu, Esra; Simsek-Kiper, Pelin Ozlem; Utine, Gulen Eda; Campos-Xavier, Belinda; Boduroglu, Koray; Bonafé, Luisa; Superti-Furga, Andrea; Unger, Sheila

    2013-12-01

    Cousin syndrome, also called pelviscapular dysplasia (OMIM 260660), is characterized by short stature, craniofacial dysmorphism, and multiple skeletal anomalies. Following its description in two sibs in 1982, no new cases have been observed until the observation of two unrelated cases in 2008 who were homozygous for frameshift mutations in TBX15. We investigated an adult individual with short stature, a complex craniofacial dysmorphism, malformed and rotated ears, short neck, elbow contractures, hypoacusis, and hypoplasia of scapula and pelvis on radiographs. We identified homozygosity for a novel nonsense mutation (c.841C>T) in TBX15 predicted to cause a premature stop (p.Arg281*) with truncation of the protein. This observation confirms that Cousin syndrome is a consistent and clinically recognizable phenotype caused by loss of function of TBX15.

  5. MBTPS2 mutations cause defective regulated intramembrane proteolysis in X-linked osteogenesis imperfecta

    Science.gov (United States)

    Lindert, Uschi; Cabral, Wayne A.; Ausavarat, Surasawadee; Tongkobpetch, Siraprapa; Ludin, Katja; Barnes, Aileen M.; Yeetong, Patra; Weis, Maryann; Krabichler, Birgit; Srichomthong, Chalurmpon; Makareeva, Elena N.; Janecke, Andreas R.; Leikin, Sergey; Röthlisberger, Benno; Rohrbach, Marianne; Kennerknecht, Ingo; Eyre, David R.; Suphapeetiporn, Kanya; Giunta, Cecilia; Marini, Joan C.; Shotelersuk, Vorasuk

    2016-01-01

    Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia. We identified an X-linked recessive form of OI caused by defects in MBTPS2, which encodes site-2 metalloprotease (S2P). MBTPS2 missense mutations in two independent kindreds with moderate/severe OI cause substitutions at highly conserved S2P residues. Mutant S2P has normal stability, but impaired functioning in regulated intramembrane proteolysis (RIP) of OASIS, ATF6 and SREBP transcription factors, consistent with decreased proband secretion of type I collagen. Further, hydroxylation of the collagen lysine residue (K87) critical for crosslinking is reduced in proband bone tissue, consistent with decreased lysyl hydroxylase 1 in proband osteoblasts. Reduced collagen crosslinks presumptively undermine bone strength. Also, proband osteoblasts have broadly defective differentiation. These mutations provide evidence that RIP plays a fundamental role in normal bone development. PMID:27380894

  6. Detection of Novel Mutation in Ccm3 Causes Familial Cerebral Cavernous Malformations.

    Science.gov (United States)

    Scimone, Concetta; Bramanti, Placido; Ruggeri, Alessia; Katsarou, Zoe; Donato, Luigi; Sidoti, Antonina; D'Angelo, Rosalia

    2015-11-01

    Cerebral cavernous malformations are vascular lesions that usually involve brain micro-vessels. They can occur both in a sporadic form and familial one. Causes of familial forms are mutations at three loci: CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10. Here, we describe a novel CCM3 missense mutation (c.422T>G) detected in two Greek brothers showing multiple lesions at magnetic resonance imaging; to date, only the youngest is symptomatic. Bioinformatics tools showed this novel variant causes a loss of function in Pdcd10 protein due to its localization in the eighth helix and, particularly, affects Leu141, a highly conserved amino acid. Roles of Pdcd10 in angiogenesis regulation and its association with early development of cerebral cavernous malformations were also considered.

  7. Mutation spectrum and genotype-phenotype correlation of hearing loss patients caused by SLC26A4 mutations in the Japanese: a large cohort study.

    Science.gov (United States)

    Miyagawa, Maiko; Nishio, Shin-Ya; Usami, Shin-Ichi

    2014-05-01

    Mutations in SLC26A4 cause a broad phenotypic spectrum, from typical Pendred syndrome to nonsyndromic hearing loss associated with enlarged vestibular aqueduct. Identification of these mutations is important for accurate diagnosis, proper medical management and appropriate genetic counseling and requires updated information regarding spectrum, clinical characteristics and genotype-phenotype correlations, based on a large cohort. In 100 patients with bilateral enlarged vestibular aqueduct among 1511 Japanese hearing loss probands registered in our gene bank, goiter data were available for 79, of whom 15 had Pendred syndrome and 64 had nonsyndromic hearing loss. We clarified the mutation spectrum for the SLC26A4 mutations and also summarized hearing levels, progression, fluctuation and existence of genotype-phenotype correlation. SLC26A4 mutations were identified in 82 of the 100 patients (82.0%). Of the Pendred syndrome patients, 93% (14/15) were carriers, as were 77% (49/64) of the nonsyndromic hearing loss patients. Clinical characteristics of patients with SLC26A4 mutations were congenital, fluctuating and progressive hearing loss usually associated with vertigo and/or goiter. We found no genotype-phenotype correlations, indicating that, unlike in the case of GJB2 mutations, the phenotype cannot be predicted from the genotype. Our mutation analysis confirmed the importance of mutations in the SLC26A4 gene among hearing loss patients with enlarged vestibular aqueduct and revealed the mutation spectrum, essential information when performing genetic testing.

  8. Chromatin remodeling by the CHD7 protein is impaired by mutations that cause human developmental disorders

    OpenAIRE

    Bouazoune, Karim; Kingston, Robert Edward

    2012-01-01

    Mutations in the CHD7 gene cause human developmental disorders including CHARGE syndrome. Genetic studies in model organisms have further established CHD7 as a central regulator of vertebrate development. Functional analysis of the CHD7 protein has been hampered by its large size. We used a dual-tag system to purify intact recombinant CHD7 protein and found that it is an ATP-dependent nucleosome remodeling factor. Biochemical analyses indicate that CHD7 has characteristics distinct from SWI/S...

  9. Observational cohort study of ventricular arrhythmia in adults with Marfan syndrome caused by FBN1 mutations.

    Directory of Open Access Journals (Sweden)

    Ali Aydin

    Full Text Available BACKGROUND: Marfan syndrome is associated with ventricular arrhythmia but risk factors including FBN1 mutation characteristics require elucidation. METHODS AND RESULTS: We performed an observational cohort study of 80 consecutive adults (30 men, 50 women aged 42±15 years with Marfan syndrome caused by FBN1 mutations. We assessed ventricular arrhythmia on baseline ambulatory electrocardiography as >10 premature ventricular complexes per hour (>10 PVC/h, as ventricular couplets (Couplet, or as non-sustained ventricular tachycardia (nsVT, and during 31±18 months of follow-up as ventricular tachycardia (VT events (VTE such as sudden cardiac death (SCD, and sustained ventricular tachycardia (sVT. We identified >10 PVC/h in 28 (35%, Couplet/nsVT in 32 (40%, and VTE in 6 patients (8%, including 3 with SCD (4%. PVC>10/h, Couplet/nsVT, and VTE exhibited increased N-terminal pro-brain natriuretic peptide serum levels(P10/h and Couplet/nsVT also related to increased indexed end-systolic LV diameters (P = .024 and P = .020, to moderate mitral valve regurgitation (P = .018 and P = .003, and to prolonged QTc intervals (P = .001 and P = .006, respectively. Moreover, VTE related to mutations in exons 24-32 (P = .021. Kaplan-Meier analysis corroborated an association of VTE with increased NT-proBNP (P<.001 and with mutations in exons 24-32 (P<.001. CONCLUSIONS: Marfan syndrome with causative FBN1 mutations is associated with an increased risk for arrhythmia, and affected persons may require life-long monitoring. Ventricular arrhythmia on electrocardiography, signs of myocardial dysfunction and mutations in exons 24-32 may be risk factors of VTE.

  10. Loss of function mutations in HARS cause a spectrum of inherited peripheral neuropathies.

    Science.gov (United States)

    Safka Brozkova, Dana; Deconinck, Tine; Griffin, Laurie Beth; Ferbert, Andreas; Haberlova, Jana; Mazanec, Radim; Lassuthova, Petra; Roth, Christian; Pilunthanakul, Thanita; Rautenstrauss, Bernd; Janecke, Andreas R; Zavadakova, Petra; Chrast, Roman; Rivolta, Carlo; Zuchner, Stephan; Antonellis, Anthony; Beg, Asim A; De Jonghe, Peter; Senderek, Jan; Seeman, Pavel; Baets, Jonathan

    2015-08-01

    Inherited peripheral neuropathies are a genetically heterogeneous group of disorders characterized by distal muscle weakness and sensory loss. Mutations in genes encoding aminoacyl-tRNA synthetases have been implicated in peripheral neuropathies, suggesting that these tRNA charging enzymes are uniquely important for the peripheral nerve. Recently, a mutation in histidyl-tRNA synthetase (HARS) was identified in a single patient with a late-onset, sensory-predominant peripheral neuropathy; however, the genetic evidence was lacking, making the significance of the finding unclear. Here, we present clinical, genetic, and functional data that implicate HARS mutations in inherited peripheral neuropathies. The associated phenotypic spectrum is broad and encompasses axonal and demyelinating motor and sensory neuropathies, including four young patients presenting with pure motor axonal neuropathy. Genome-wide linkage studies in combination with whole-exome and conventional sequencing revealed four distinct and previously unreported heterozygous HARS mutations segregating with autosomal dominant peripheral neuropathy in four unrelated families (p.Thr132Ile, p.Pro134His, p.Asp175Glu and p.Asp364Tyr). All mutations cause a loss of function in yeast complementation assays, and p.Asp364Tyr is dominantly neurotoxic in a Caenorhabditis elegans model. This study demonstrates the role of HARS mutations in peripheral neuropathy and expands the genetic and clinical spectrum of aminoacyl-tRNA synthetase-related human disease. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Distal weakness with respiratory insufficiency caused by the m.8344A > G "MERRF" mutation.

    Science.gov (United States)

    Blakely, Emma L; Alston, Charlotte L; Lecky, Bryan; Chakrabarti, Biswajit; Falkous, Gavin; Turnbull, Douglass M; Taylor, Robert W; Gorman, Grainne S

    2014-06-01

    The m.8344A>G mutation in the mt-tRNA(Lys) gene, first described in myoclonic epilepsy and ragged red fibers (MERRF), accounts for approximately 80% of mutations in individuals with MERRF syndrome. Although originally described in families with a classical syndrome of myoclonus, ataxia, epilepsy and ragged red fibers in muscle biopsy, the m.8344A>G mutation is increasingly recognised to exhibit marked phenotypic heterogeneity. This paper describes the clinical, morphological and laboratory features of an unusual phenotype in a patient harboring the m.8344A>G 'MERRF' mutation. We present the case of a middle-aged woman with distal weakness since childhood who also had ptosis and facial weakness and who developed mid-life respiratory insufficiency necessitating non-invasive nocturnal ventilator support. Neurophysiological and acetylcholine receptor antibody analyses excluded myasthenia gravis whilst molecular genetic testing excluded myotonic dystrophy, prompting a diagnostic needle muscle biopsy. Mitochondrial histochemical abnormalities including subsarcolemmal mitochondrial accumulation (ragged-red fibers) and in excess of 90% COX-deficient fibers, was seen leading to sequencing of the mitochondrial genome in muscle. This identified the m.8344A>G mutation commonly associated with the MERRF phenotype. This case extends the evolving phenotypic spectrum of the m.8344A>G mutation and emphasizes that it may cause indolent distal weakness with respiratory insufficiency, with marked histochemical defects in muscle. Our findings support consideration of screening of this gene in cases of indolent myopathy resembling distal limb-girdle muscular dystrophy in which screening of the common genes prove negative.

  12. A frameshift mutation in GRXCR2 causes recessively inherited hearing loss.

    Science.gov (United States)

    Imtiaz, Ayesha; Kohrman, David C; Naz, Sadaf

    2014-05-01

    More than 360 million humans are affected with some degree of hearing loss, either early or later in life. A genetic cause for the disorder is present in a majority of the cases. We mapped a locus (DFNB101) for hearing loss in humans to chromosome 5q in a consanguineous Pakistani family. Exome sequencing revealed an insertion mutation in GRXCR2 as the cause of moderate-to-severe and likely progressive hearing loss in the affected individuals of the family. The frameshift mutation is predicted to affect a conserved, cysteine-rich region of GRXCR2, and to result in an abnormal extension of the C-terminus. Functional studies by cell transfections demonstrated that the mutant protein is unstable and mislocalized relative to wild-type GRXCR2, consistent with a loss-of-function mutation. Targeted disruption of Grxcr2 is concurrently reported to cause hearing loss in mice. The structural abnormalities in this animal model suggest a role for GRXCR2 in the development of stereocilia bundles, specialized structures on the apical surface of sensory cells in the cochlea that are critical for sound detection. Our results indicate that GRXCR2 should be considered in differential genetic diagnosis for individuals with early onset, moderate-to-severe and progressive hearing loss.

  13. SLC4A11 Three-Dimensional Homology Model Rationalizes Corneal Dystrophy-Causing Mutations.

    Science.gov (United States)

    Badior, Katherine E; Alka, Kumari; Casey, Joseph R

    2017-03-01

    We studied the structural effects of point mutations of a membrane protein that cause genetic disease. SLC4A11 is a membrane transport protein (OH(-) /H(+) /NH3 /H2 O) of basolateral corneal endothelium, whose mutations cause some cases of congenital hereditary endothelial dystrophy and Fuchs endothelial corneal dystrophy. We created a three-dimensional homology model of SLC4A11 membrane domain, using Band 3 (SLC4A1) crystal structure as template. The homology model was assessed in silico and by analysis of mutants designed on the basis of the model. Catalytic pathway mutants p.Glu675Gln, p.His724Arg, and p.His724Ala impaired SLC4A11 transport. p.Ala720Leu, in a region of extended structure of the proposed translocation pore, failed to mature to the cell surface. p.Gly509Lys, located in an open region at the core domain/gate domain interface, had wild-type level of transport function. The molecular phenotype of 37 corneal dystrophy-causing point mutants was rationalized, based on their location in the homology model. Four map to the substrate translocation pathway, 25 to regions of close transmembrane helix packing, three to the dimeric interface, and five lie in extramembraneous loops. The model provides a view of the spectrum of effects of disease mutations on membrane protein structure and provides a tool to analyze pathogenicity of additional newly discovered SLC4A11 mutants. © 2016 WILEY PERIODICALS, INC.

  14. Recessive MYL2 mutations cause infantile type I muscle fibre disease and cardiomyopathy.

    Science.gov (United States)

    Weterman, Marian A J; Barth, Peter G; van Spaendonck-Zwarts, Karin Y; Aronica, Eleonora; Poll-The, Bwee-Tien; Brouwer, Oebele F; van Tintelen, J Peter; Qahar, Zohal; Bradley, Edward J; de Wissel, Marit; Salviati, Leonardo; Angelini, Corrado; van den Heuvel, Lambertus; Thomasse, Yolande E M; Backx, Ad P; Nürnberg, Gudrun; Nürnberg, Peter; Baas, Frank

    2013-01-01

    A cardioskeletal myopathy with onset and death in infancy, morphological features of muscle type I hypotrophy with myofibrillar disorganization and dilated cardiomyopathy was previously reported in three Dutch families. Here we report the genetic cause of this disorder. Multipoint parametric linkage analysis of six Dutch patients identified a homozygous region of 2.1 Mb on chromosome 12, which was shared between all Dutch patients, with a log of odds score of 10.82. Sequence analysis of the entire linkage region resulted in the identification of a homozygous mutation in the last acceptor splice site of the myosin regulatory light chain 2 gene (MYL2) as the genetic cause. MYL2 encodes a myosin regulatory light chain (MLC-2V). The myosin regulatory light chains bind, together with the essential light chains, to the flexible neck region of the myosin heavy chain in the hexameric myosin complex and have a structural and regulatory role in muscle contraction. The MYL2 mutation results in use of a cryptic splice site upstream of the last exon causing a frameshift and replacement of the last 32 codons by 20 different codons. Whole exome sequencing of an Italian patient with similar clinical features showed compound heterozygosity for two other mutations affecting the same exon of MYL2, also resulting in mutant proteins with altered C-terminal tails. As a consequence of these mutations, the second EF-hand domain is disrupted. EF-hands, assumed to function as calcium sensors, can undergo a conformational change upon binding of calcium that is critical for interactions with downstream targets. Immunohistochemical staining of skeletal muscle tissue of the Dutch patients showed a diffuse and weak expression of the mutant protein without clear fibre specificity, while normal protein was absent. Heterozygous missense mutations in MYL2 are known to cause dominant hypertrophic cardiomyopathy; however, none of the parents showed signs of cardiomyopathy. In conclusion, the mutations

  15. A novel ICK mutation causes ciliary disruption and lethal endocrine-cerebro-osteodysplasia syndrome.

    Science.gov (United States)

    Oud, Machteld M; Bonnard, Carine; Mans, Dorus A; Altunoglu, Umut; Tohari, Sumanty; Ng, Alvin Yu Jin; Eskin, Ascia; Lee, Hane; Rupar, C Anthony; de Wagenaar, Nathalie P; Wu, Ka Man; Lahiry, Piya; Pazour, Gregory J; Nelson, Stanley F; Hegele, Robert A; Roepman, Ronald; Kayserili, Hülya; Venkatesh, Byrappa; Siu, Victoria M; Reversade, Bruno; Arts, Heleen H

    2016-01-01

    Endocrine-cerebro-osteodysplasia (ECO) syndrome [MIM:612651] caused by a recessive mutation (p.R272Q) in Intestinal cell kinase (ICK) shows significant clinical overlap with ciliary disorders. Similarities are strongest between ECO syndrome, the Majewski and Mohr-Majewski short-rib thoracic dysplasia (SRTD) with polydactyly syndromes, and hydrolethalus syndrome. In this study, we present a novel homozygous ICK mutation in a fetus with ECO syndrome and compare the effect of this mutation with the previously reported ICK variant on ciliogenesis and cilium morphology. Through homozygosity mapping and whole-exome sequencing, we identified a second variant (c.358G > T; p.G120C) in ICK in a Turkish fetus presenting with ECO syndrome. In vitro studies of wild-type and mutant mRFP-ICK (p.G120C and p.R272Q) revealed that, in contrast to the wild-type protein that localizes along the ciliary axoneme and/or is present in the ciliary base, mutant proteins rather enrich in the ciliary tip. In addition, immunocytochemistry revealed a decreased number of cilia in ICK p.R272Q-affected cells. Through identification of a novel ICK mutation, we confirm that disruption of ICK causes ECO syndrome, which clinically overlaps with the spectrum of ciliopathies. Expression of ICK-mutated proteins result in an abnormal ciliary localization compared to wild-type protein. Primary fibroblasts derived from an individual with ECO syndrome display ciliogenesis defects. In aggregate, our findings are consistent with recent reports that show that ICK regulates ciliary biology in vitro and in mice, confirming that ECO syndrome is a severe ciliopathy.

  16. A novel point mutation in CD18 causing leukocyte adhesion deficiency in a Chinese patient

    Institute of Scientific and Technical Information of China (English)

    LI Li; JIN Ying-ying; CAO Rui-ming; CHEN Tong-xin

    2010-01-01

    Background Leukocyte adhesion deficiency type 1 (LAD-1)is a rare, autosomal recessive inherited immunodeficiency disease characterized by recurrent severe bacterial infection, impaired pus formation, poor wound healing, associated with the mutation in the CD18 gene responsible for the ability of the leucocytes to migrate from the blood stream towards the site of inflammation.Correct and early diagnosis of LAD-1 is vital to the success of treatment and prevention of aggressive infections.The purpose of this study was to collect the clinical findings of the disease and to identify the genetic entity.Methods CD18 expression in the peripheral blood leukocytes from the patient, his parents and normal control was measured with flow cytometry.The entire coding regions of the CD18 gene were screened with direct sequencing genomic DNA.Results CD18 expression level on this patient's leukocyte surface was significantly decreased, with normal level in control group, his father and mother.Gene analysis revealed that this patient had a homozygous c.899A>T missense mutation in exon 8 of CD18 gene, causing the substitution of Asp to Val at the 300 amino acid.His parents were both heterozygous carriers while no such mutation was found in 50 normal controls.Conclusion This study disclosed a novel point mutation Asp 300 Val located in a highly conserved region (HCR) of CD18 and confirmed the heterogeneity of the mutations causing LAD-1, indicating it was quite beneficial to establish correct and early diagnosis in children with severe LAD-1.

  17. Dentin phosphoprotein compound mutation in dentin sialophosphoprotein causes dentinogenesis imperfecta type III.

    Science.gov (United States)

    Dong, Juan; Gu, TingTing; Jeffords, Leticia; MacDougall, Mary

    2005-01-30

    A rare compound mutation involving a 36 bp deletion and 18 bp insertion within exon 5 of the dentin sialophosphoprotein (DSPP) gene has been identified in a family with dentinogenesis imperfecta type III (DGI-III). The DSPP gene encodes two major tooth matrix proteins dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). DSPP mutations associated with DGI-III results in an in frame truncation of the serine aspartic acid triplet repeat found in DPP near the highly conserved carboxyl terminal region shortening the protein by six amino acids. Clinically this family presents with discolored amber opalescent teeth and severe attrition of the tooth structure. This study is the first report of a mutation within DPP associated with a genetic dentin disease. Our study indicates that DGI-III is allelic with some forms of DGI-II with and without progressive hearing loss and dentin dysplasia type II that have been shown to be caused by mutations within the DSP coding or signal peptide regions.

  18. Mutations in PNKP cause recessive ataxia with oculomotor apraxia type 4.

    Science.gov (United States)

    Bras, Jose; Alonso, Isabel; Barbot, Clara; Costa, Maria Manuela; Darwent, Lee; Orme, Tatiana; Sequeiros, Jorge; Hardy, John; Coutinho, Paula; Guerreiro, Rita

    2015-03-05

    Hereditary autosomal-recessive cerebellar ataxias are a genetically and clinically heterogeneous group of disorders. We used homozygosity mapping and exome sequencing to study a cohort of nine Portuguese families who were identified during a nationwide, population-based, systematic survey as displaying a consistent phenotype of recessive ataxia with oculomotor apraxia (AOA). The integration of data from these analyses led to the identification of the same homozygous PNKP (polynucleotide kinase 3'-phosphatase) mutation, c.1123G>T (p.Gly375Trp), in three of the studied families. When analyzing this particular gene in the exome sequencing data from the remaining cohort, we identified homozygous or compound-heterozygous mutations in five other families. PNKP is a dual-function enzyme with a key role in different pathways of DNA-damage repair. Mutations in this gene have previously been associated with an autosomal-recessive syndrome characterized by microcephaly; early-onset, intractable seizures; and developmental delay (MCSZ). The finding of PNKP mutations associated with recessive AOA extends the phenotype associated with this gene and identifies a fourth locus that causes AOA. These data confirm that MCSZ and some forms of ataxia share etiological features, most likely reflecting the role of PNKP in DNA-repair mechanisms.

  19. Sphingosine-1-phosphate lyase mutations cause primary adrenal insufficiency and steroid-resistant nephrotic syndrome

    Science.gov (United States)

    Prasad, Rathi; Hadjidemetriou, Irene; Meimaridou, Eirini; Buonocore, Federica; Saleem, Moin; Hurcombe, Jenny; Bierzynska, Agnieszka; Barbagelata, Eliana; Bergadá, Ignacio; Cassinelli, Hamilton; Das, Urmi; Krone, Ruth; Hacihamdioglu, Bulent; Sari, Erkan; Yesilkaya, Ediz; Storr, Helen L.; Clemente, Maria; Fernandez-Cancio, Monica; Camats, Nuria; Ram, Nanik; Achermann, John C.; Van Veldhoven, Paul P.; Guasti, Leonardo; Braslavsky, Debora; Guran, Tulay; Metherell, Louise A.

    2017-01-01

    Primary adrenal insufficiency is life threatening and can present alone or in combination with other comorbidities. Here, we have described a primary adrenal insufficiency syndrome and steroid-resistant nephrotic syndrome caused by loss-of-function mutations in sphingosine-1-phosphate lyase (SGPL1). SGPL1 executes the final decisive step of the sphingolipid breakdown pathway, mediating the irreversible cleavage of the lipid-signaling molecule sphingosine-1-phosphate (S1P). Mutations in other upstream components of the pathway lead to harmful accumulation of lysosomal sphingolipid species, which are associated with a series of conditions known as the sphingolipidoses. In this work, we have identified 4 different homozygous mutations, c.665G>A (p.R222Q), c.1633_1635delTTC (p.F545del), c.261+1G>A (p.S65Rfs*6), and c.7dupA (p.S3Kfs*11), in 5 families with the condition. In total, 8 patients were investigated, some of whom also manifested other features, including ichthyosis, primary hypothyroidism, neurological symptoms, and cryptorchidism. Sgpl1–/– mice recapitulated the main characteristics of the human disease with abnormal adrenal and renal morphology. Sgpl1–/– mice displayed disrupted adrenocortical zonation and defective expression of steroidogenic enzymes as well as renal histology in keeping with a glomerular phenotype. In summary, we have identified SGPL1 mutations in humans that perhaps represent a distinct multisystemic disorder of sphingolipid metabolism. PMID:28165343

  20. A MAYAN FOUNDER MUTATION IS A COMMON CAUSE OF DEAFNESS IN GUATEMALA

    Science.gov (United States)

    Carranza, Claudia; Menendez, Ibis; Herrera, Mariana; Castellanos, Patricia; Amado, Carlos; Maldonado, Fabiola; Rosales, Luisa; Escobar, Nancy; Guerra, Mariela; Alvarez, Darwin; Foster, Joseph; Guo, Shengru; Blanton, Susan H.; Bademci, Guney; Tekin, Mustafa

    2017-01-01

    SUMMARY Over 5% of the world population have varying degrees of hearing loss. Mutations in GJB2 are the most common cause of autosomal recessive non-syndromic hearing loss (NSHL) in many populations. The frequency and type of mutations are influenced by ethnicity. Guatemala is a multi-ethnic country with four major populations: Maya, Ladino, Xinca, and Garifuna. To determine the mutation profile of GJB2 in a NSHL population from Guatemala, we sequenced both exons of GJB2 in 133 unrelated families. A total of six pathogenic variants were detected. The most frequent pathogenic variant is c.131G>A (p.Trp44*) detected in 21 of 266 alleles. We show that c.131G>A is associated with a conserved haplotype in Guatemala suggesting a single founder. The majority of Mayan population lives in the west region of the country from where all c.131G>A carriers originated. Further analysis of genome-wide variation of individuals carrying the c.131G>A mutation compared to those of Native American, European, and African populations shows a close match with the Mayan population. PMID:26346709

  1. Paternal age effect mutations and selfish spermatogonial selection: causes and consequences for human disease.

    Science.gov (United States)

    Goriely, Anne; Wilkie, Andrew O M

    2012-02-10

    Advanced paternal age has been associated with an increased risk for spontaneous congenital disorders and common complex diseases (such as some cancers, schizophrenia, and autism), but the mechanisms that mediate this effect have been poorly understood. A small group of disorders, including Apert syndrome (caused by FGFR2 mutations), achondroplasia, and thanatophoric dysplasia (FGFR3), and Costello syndrome (HRAS), which we collectively term "paternal age effect" (PAE) disorders, provides a good model to study the biological and molecular basis of this phenomenon. Recent evidence from direct quantification of PAE mutations in sperm and testes suggests that the common factor in the paternal age effect lies in the dysregulation of spermatogonial cell behavior, an effect mediated molecularly through the growth factor receptor-RAS signal transduction pathway. The data show that PAE mutations, although arising rarely, are positively selected and expand clonally in normal testes through a process akin to oncogenesis. This clonal expansion, which is likely to take place in the testes of all men, leads to the relative enrichment of mutant sperm over time-explaining the observed paternal age effect associated with these disorders-and in rare cases to the formation of testicular tumors. As regulation of RAS and other mediators of cellular proliferation and survival is important in many different biological contexts, for example during tumorigenesis, organ homeostasis and neurogenesis, the consequences of selfish mutations that hijack this process within the testis are likely to extend far beyond congenital skeletal disorders to include complex diseases, such as neurocognitive disorders and cancer predisposition.

  2. Novel mutations in TLR genes cause hyporesponsiveness to Mycobacterium avium subsp. paratuberculosis infection

    Directory of Open Access Journals (Sweden)

    Skrabana Rostislav

    2009-05-01

    Full Text Available Abstract Background Toll like receptors (TLR play the central role in the recognition of pathogen associated molecular patterns (PAMPs. Mutations in the TLR1, TLR2 and TLR4 genes may change the ability to recognize PAMPs and cause altered responsiveness to the bacterial pathogens. Results The study presents association between TLR gene mutations and increased susceptibility to Mycobacterium avium subsp. paratuberculosis (MAP infection. Novel mutations in TLR genes (TLR1- Ser150Gly and Val220Met; TLR2 – Phe670Leu were statistically correlated with the hindrance in recognition of MAP legends. This correlation was confirmed subsequently by measuring the expression levels of cytokines (IL-4, IL-8, IL-10, IL-12 and IFN-γ in the mutant and wild type moDCs (mocyte derived dendritic cells after challenge with MAP cell lysate or LPS. Further in silico analysis of the TLR1 and TLR4 ectodomains (ECD revealed the polymorphic nature of the central ECD and irregularities in the central LRR (leucine rich repeat motifs. Conclusion The most critical positions that may alter the pathogen recognition ability of TLR were: the 9th amino acid position in LRR motif (TLR1–LRR10 and 4th residue downstream to LRR domain (exta-LRR region of TLR4. The study describes novel mutations in the TLRs and presents their association with the MAP infection.

  3. Mutations in Either TUBB or MAPRE2 Cause Circumferential Skin Creases Kunze Type

    Science.gov (United States)

    Isrie, Mala; Breuss, Martin; Tian, Guoling; Hansen, Andi Harley; Cristofoli, Francesca; Morandell, Jasmin; Kupchinsky, Zachari A.; Sifrim, Alejandro; Rodriguez-Rodriguez, Celia Maria; Dapena, Elena Porta; Doonanco, Kurston; Leonard, Norma; Tinsa, Faten; Moortgat, Stéphanie; Ulucan, Hakan; Koparir, Erkan; Karaca, Ender; Katsanis, Nicholas; Marton, Valeria; Vermeesch, Joris Robert; Davis, Erica E.; Cowan, Nicholas J.; Keays, David Anthony; Van Esch, Hilde

    2015-01-01

    Circumferential skin creases Kunze type (CSC-KT) is a specific congenital entity with an unknown genetic cause. The disease phenotype comprises characteristic circumferential skin creases accompanied by intellectual disability, a cleft palate, short stature, and dysmorphic features. Here, we report that mutations in either MAPRE2 or TUBB underlie the genetic origin of this syndrome. MAPRE2 encodes a member of the microtubule end-binding family of proteins that bind to the guanosine triphosphate cap at growing microtubule plus ends, and TUBB encodes a β-tubulin isotype that is expressed abundantly in the developing brain. Functional analyses of the TUBB mutants show multiple defects in the chaperone-dependent tubulin heterodimer folding and assembly pathway that leads to a compromised yield of native heterodimers. The TUBB mutations also have an impact on microtubule dynamics. For MAPRE2, we show that the mutations result in enhanced MAPRE2 binding to microtubules, implying an increased dwell time at microtubule plus ends. Further, in vivo analysis of MAPRE2 mutations in a zebrafish model of craniofacial development shows that the variants most likely perturb the patterning of branchial arches, either through excessive activity (under a recessive paradigm) or through haploinsufficiency (dominant de novo paradigm). Taken together, our data add CSC-KT to the growing list of tubulinopathies and highlight how multiple inheritance paradigms can affect dosage-sensitive biological systems so as to result in the same clinical defect. PMID:26637975

  4. A novel mutation in the AGXT gene causing primary hyperoxaluria type I: genotype–phenotype correlation

    Indian Academy of Sciences (India)

    SAOUSSEN M’DIMEGH; CÉCILE AQUAVIVA- BOURDAIN; ASMA OMEZZINE; IBTIHEL M’BAREK; GENEVIÉVE SOUCHE; DORSAF ZELLAMA; KAMEL ABIDI; ABDELATTIF ACHOUR; TAHAR GARGAH; SAOUSSEN ABROUG; ALI BOUSLAMA

    2016-09-01

    Primary hyperoxaluria type I (PH1) is an autosomal recessive metabolic disorder caused by inherited mutations in the AGXT gene encoding liver peroxisomal alanine : glyoxylate aminotransferase (AGT) which is deficient or mistargeted to mitochon-dria. PH1 shows considerable phenotypic and genotypic heterogeneity. The incidence and severity of PH1 varies in different geographic regions. DNA samples of the affected members from two unrelated Tunisian families were tested by amplifying and sequencing each of the AGXT exons and intron–exon junctions. We identified a novel frameshift mutation in the AGXT gene, the c.406_410dupACTGC resulting in a truncated protein (p.Gln137Hisfs*19). It is found in homozygous state in two nonconsanguineous unrelated families from Tunisia. These molecular findings provide genotype/phenotype correlations in the intrafamilial phenotypic and permit accurate carrier detection, and prenatal diagnosis. The novel p.G ln137Hisfs*19 mutation detected in our study extend the spectrum of knownAGXT gene mutations in Tunisia.

  5. A Novel Missense Mutation in Oncostatin M Receptor Beta Causing Primary Localized Cutaneous Amyloidosis

    Directory of Open Access Journals (Sweden)

    Marjan Saeedi

    2014-01-01

    Full Text Available Primary localized cutaneous amyloidosis (PLCA is a chronic skin disorder, caused by amyloid material deposition in the upper dermis. Autosomal dominant PLCA has been mapped earlier to pathogenic missense mutations in the OSMR gene, which encodes the oncostatin M receptor ß subunit (OSMRß. OSMRß is interleukin-6 family cytokine receptors and possesses two ligands, oncostatin M and interleukin-31, which both have biologic roles in inflammation and keratinocyte cell proliferation, differentiation, and apoptosis. Here, we identified a new OSMR mutation in a Kurdish family for the first time. Blood samples were taken from all the affected individuals in the family. DNA extraction was performed using salting out technique. Primers were designed for intron flanking individual exons of OSMR gene which were subjected to direct sequencing after PCR amplification for each sample. Sequencing showed a C/T substitution at position 613 in the proband. This mutation results in an L613S (leucine 613 to serine amino acid change. The identified mutation was observed in all affected family members but not in 100 ethnically matched healthy controls. Elucidating the molecular basis of familial PLCA provides new insight into mechanisms of itch in human skin and may lead to new therapeutic targets for pruritus.

  6. A SIGMAR1 splice-site mutation causes distal hereditary motor neuropathy.

    Science.gov (United States)

    Li, Xiaobo; Hu, Zhengmao; Liu, Lei; Xie, Yongzhi; Zhan, Yajing; Zi, Xiaohong; Wang, Junling; Wu, Lixiang; Xia, Kun; Tang, Beisha; Zhang, Ruxu

    2015-06-16

    To identify the underlying genetic cause in a consanguineous Chinese family segregating distal hereditary motor neuropathy (dHMN) in an autosomal recessive pattern. We used whole-exome sequencing and homozygosity mapping to detect the genetic variant in 2 affected individuals of the consanguineous Chinese family with dHMN. RNA analysis of peripheral blood leukocytes and immunofluorescence and immunoblotting of stable cell lines were performed to support the pathogenicity of the identified mutation. We identified 3 shared novel homozygous variants in 3 shared homozygous regions of the affected individuals. Sequencing of these 3 variants in family members revealed the c.151+1G>T mutation in SIGMAR1 gene, which located in homozygous region spanning approximately 5.3 Mb at chromosome 9p13.1-p13.3, segregated with the dHMN phenotype. The mutation causes an alternative splicing event and generates a transcript variant with an in-frame deletion of 60 base pairs in exon 1 (c.92_151del), and results in an internally shortened protein σ1R(31_50del). The proteasomal inhibitor treatment increased the intracellular amount of σ1R(31_50del) and led to the formation of nuclear aggregates. Stable expressing σ1R(31_50del) induced endoplasmic reticulum stress and enhanced apoptosis. The homozygous c.151+1G>T mutation in SIGMAR1 caused a novel form of autosomal recessive dHMN in a Chinese consanguineous family. Endoplasmic reticulum stress may have a role in the pathogenesis of dHMN. © 2015 American Academy of Neurology.

  7. Two novel connexin32 mutations cause early onset X-linked Charcot-Marie-Tooth disease

    Directory of Open Access Journals (Sweden)

    Sand Jette C

    2007-07-01

    Full Text Available Abstract Background X-linked Charcot-Marie Tooth (CMT is caused by mutations in the connexin32 gene that encodes a polypeptide which is arranged in hexameric array and form gap junctions. Methods We describe two novel mutations in the connexin32 gene in two Norwegian families. Results Family 1 had a c.225delG (R75fsX83 which causes a frameshift and premature stop codon at position 247. This probably results in a shorter non-functional protein structure. Affected individuals had an early age at onset usually in the first decade. The symptoms were more severe in men than women. All had severe muscle weakness in the legs. Several abortions were observed in this family. Family 2 had a c.536 G>A (C179Y transition which causes a change of the highly conserved cysteine residue, i.e. disruption of at least one of three disulfide bridges. The mean age at onset was in the first decade. Muscle wasting was severe and correlated with muscle weakness in legs. The men and one woman also had symptom from their hands. The neuropathy is demyelinating and the nerve conduction velocities were in the intermediate range (25–49 m/s. Affected individuals had symmetrical clinical findings, while the neurophysiology revealed minor asymmetrical findings in nerve conduction velocity in 6 of 10 affected individuals. Conclusion The two novel mutations in the connexin32 gene are more severe than the majority of previously described mutations possibly due to the severe structural change of the gap junction they encode.

  8. Mutation Update and Genotype–Phenotype Correlations of Novel and Previously Described Mutations in TPM2 and TPM3 Causing Congenital Myopathies

    Science.gov (United States)

    Marttila, Minttu; Lehtokari, Vilma-Lotta; Marston, Steven; Nyman, Tuula A.; Barnerias, Christine; Beggs, Alan H.; Bertini, Enrico; Ceyhan-Birsoy, OÖzge; Cintas, Pascal; Gerard, Marion; Gilbert-Dussardier, Brigitte; Hogue, Jacob S.; Longman, Cheryl; Eymard, Bruno; Frydman, Moshe; Kang, Peter B.; Klinge, Lars; Kolski, Hanna; Lochmüller, Hans; Magy, Laurent; Manel, Véronique; Mayer, Michèle; Mercuri, Eugenio; North, Kathryn N.; Peudenier-Robert, Sylviane; Pihko, Helena; Probst, Frank J.; Reisin, Ricardo; Stewart, Willie; Taratuto, Ana Lia; de Visser, Marianne; Wilichowski, Ekkehard; Winer, John; Nowak, Kristen; Laing, Nigel G.; Winder, Tom L.; Monnier, Nicole; Clarke, Nigel F.; Pelin, Katarina; Grönholm, Mikaela; Wallgren-Pettersson, Carina

    2014-01-01

    Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy, cap myopathy, core-rod myopathy, congenital fiber-type disproportion, distal arthrogryposes, and Escobar syndrome. We correlate the clinical picture of these diseases with novel (19) and previously reported (31) mutations of the TPM2 and TPM3 genes. Included are altogether 93 families: 53 with TPM2 mutations and 40 with TPM3 mutations. Thirty distinct pathogenic variants of TPM2 and 20 of TPM3 have been published or listed in the Leiden Open Variant Database (http://www.dmd.nl/). Most are heterozygous changes associated with autosomal-dominant disease. Patients with TPM2 mutations tended to present with milder symptoms than those with TPM3 mutations, DA being present only in the TPM2 group. Previous studies have shown that five of the mutations in TPM2 and one in TPM3 cause increased Ca2+ sensitivity resulting in a hypercontractile molecular phenotype. Patients with hypercontractile phenotype more often had contractures of the limb joints (18/19) and jaw (6/19) than those with nonhypercontractile ones (2/22 and 1/22), whereas patients with the non-hypercontractile molecular phenotype more often (19/22) had axial contractures than the hypercontractile group (7/19). Our in silico predictions show that most mutations affect tropomyosin–actin association or tropomyosin head-to-tail binding. PMID:24692096

  9. Homozygous EXOSC3 mutation c.92G→C, p.G31A is a founder mutation causing severe pontocerebellar hypoplasia type 1 among the Czech Roma.

    Science.gov (United States)

    Schwabova, Jaroslava; Brozkova, Dana Safka; Petrak, Borivoj; Mojzisova, Mahulena; Pavlickova, Klara; Haberlova, Jana; Mrazkova, Lenka; Hedvicakova, Petra; Hornofova, Ludmila; Kaluzova, Marie; Fencl, Filip; Krutova, Marcela; Zamecnik, Josef; Seeman, Pavel

    2013-12-01

    Pontocerebellar hypoplasia type 1 (PCH1) is characterized by cerebellar and anterior horn motor neuron degeneration and loss, signs of spinal muscular atrophy plus. Patients manifest severe perinatal weakness, hypotonia, and respiratory insufficiency, causing death frequently before the age of 1 year. Recently, causative mutations in EXOSC3 were reported in a majority of PCH1 patients, but the detailed clinical phenotype caused by EXOSC3 mutations, genotype-phenotype correlations, and prevalent mutations in specific ethnic groups is not yet known. Three unrelated Czech Roma patients with PCH1 were investigated clinically, electrophysiologically, neuroradiologically, and neuropathologically (patients 1 and 2). The entire coding region of the EXOSC3 gene, including the adjacent intron sequences, was sequenced in all three patients. The same mutation c.92G→C, p.G31A in EXOSC3 was found in all three affected patients in homozygous state and in heterozygous state in the parents from two of the families. Haplotype analysis with four flanking microsatellite markers showed identical haplotype in 9 out of 11 haplotypes carrying the c.92G→C, p.G31A mutation. Furthermore, four heterozygotes for this mutation were found in anonymous DNA samples from 90 unrelated Roma individuals. All four of these samples shared the same haplotype. No heterozygous sample was found among 120 anonymous DNA samples from Czech non-Roma individuals with no familial relation. It may therefore be concluded that EXOSC3 c.92G→C, p.G31A mutation is a founder mutation with high prevalence among the Czech Roma causing a similar and particularly severe phenotype of PCH1. These observations from the Czech Roma may have consequences also for other Roma from other countries. PCH1 caused by EXOSC3 founder mutation c.92G→C, p.G31A extends the list of autosomal recessive disorders rare among the general population but more frequent among Roma at least in the Czech Republic.

  10. Myopathy mutations in alpha-skeletal-muscle actin cause a range of molecular defects.

    Science.gov (United States)

    Costa, Céline F; Rommelaere, Heidi; Waterschoot, Davy; Sethi, Kamaljit K; Nowak, Kristen J; Laing, Nigel G; Ampe, Christophe; Machesky, Laura M

    2004-07-01

    Mutations in the gene encoding alpha-skeletal-muscle actin, ACTA1, cause congenital myopathies of various phenotypes that have been studied since their discovery in 1999. Although much is now known about the clinical aspects of myopathies resulting from over 60 different ACTA1 mutations, we have very little evidence for how mutations alter the behavior of the actin protein and thus lead to disease. We used a combination of biochemical and cell biological analysis to classify 19 myopathy mutants and found a range of defects in the actin. Using in vitro expression systems, we probed actin folding and actin's capacity to interact with actin-binding proteins and polymerization. Only two mutants failed to fold; these represent recessive alleles, causing severe myopathy, indicating that patients produce nonfunctional actin. Four other mutants bound tightly to cyclase-associated protein, indicating a possible instability in the nucleotide-binding pocket, and formed rods and aggregates in cells. Eleven mutants showed defects in the ability to co-polymerize with wild-type actin. Some of these could incorporate into normal actin structures in NIH 3T3 fibroblasts, but two of the three tested also formed aggregates. Four mutants showed no defect in vitro but two of these formed aggregates in cells, indicating functional defects that we have not yet tested for. Overall, we found a range of defects and behaviors of the mutants in vitro and in cultured cells, paralleling the complexity of actin-based muscle myopathy phenotypes.

  11. A new mutation of the fukutin gene causing late-onset limb girdle muscular dystrophy.

    Science.gov (United States)

    Riisager, M; Duno, M; Hansen, F Juul; Krag, T O; Vissing, C R; Vissing, J

    2013-07-01

    Defects in glycosylations of α-dystroglycan are associated with mutations in several genes, including the fukutin gene (FKTN). Hypoglycosylation of α-dystroglycan results in several forms of muscular dystrophy with variable phenotype. Outside Japan, the prevalence of muscular dystrophies related to aberrations of FKTN is rare, with only eight reported cases of limb girdle phenotype (LGMD2M). We describe the mildest affected patient outside Japan with genetically confirmed LGMD2M and onset of symptoms at age 14. She was brought to medical attention at age 12, not because of muscle weakness, but due to episodes of tachycardia caused by Wolff-Parkinson-White syndrome. On examination, she had rigid spine syndrome, a typical limb girdle dystrophy pattern of muscle weakness, cardiomyopathy, and serum CK levels >2000 IU/L (normal G; p.Y306C mutation in the FKTN gene was found. The case confirms FKTN mutations as a cause of LGMD2M without mental retardation and expands the phenotypic spectrum for LGMD2M to include cardiomyopathy and rigid spine syndrome in the mildest affected non-Japanese patient reported so far.

  12. CCDC103 mutations cause primary ciliary dyskinesia by disrupting assembly of ciliary dynein arms

    Science.gov (United States)

    Panizzi, Jennifer R.; Becker-Heck, Anita; Castleman, Victoria H.; Al-Mutairi, Dalal; Liu, Yan; Loges, Niki T.; Pathak, Narendra; Austin-Tse, Christina; Sheridan, Eamonn; Schmidts, Miriam; Olbrich, Heike; Werner, Claudius; Häffner, Karsten; Hellman, Nathan; Chodhari, Rahul; Gupta, Amar; Kramer-Zucker, Albrecht; Olale, Felix; Burdine, Rebecca D.; Schier, Alexander F.; O’Callaghan, Christopher; Chung, Eddie MK; Reinhardt, Richard; Mitchison, Hannah M.; King, Stephen M.; Omran, Heymut; Drummond, Iain A.

    2012-01-01

    Cilia are essential for fertilization, respiratory clearance, cerebrospinal fluid circulation, and to establish laterality1. Cilia motility defects cause Primary Ciliary Dyskinesia (PCD, MIM 242650), a disorder affecting 1:15-30,000 births. Cilia motility requires the assembly of multisubunit dynein arms that drive cilia bending2. Despite progress in understanding the genetic basis of PCD, mutations remain to be identified for several PCD linked loci3. Here we show that the zebrafish cilia paralysis mutant schmalhanstn222 (smh) mutant encodes the coiled-coil domain containing 103 protein (Ccdc103), a foxj1a regulated gene. Screening 146 unrelated PCD families identified patients in six families with reduced outer dynein arms, carrying mutations in CCDC103. Dynein arm assembly in smh mutant zebrafish was rescued by wild-type but not mutant human CCDC103. Chlamydomonas Ccdc103 functions as a tightly bound, axoneme-associated protein. The results identify Ccdc103 as a novel dynein arm attachment factor that when mutated causes Primary Ciliary Dyskinesia. PMID:22581229

  13. Mutation in noncoding RNA RNU12 causes early onset cerebellar ataxia.

    Science.gov (United States)

    Elsaid, Mahmoud Fawzi; Chalhoub, Nader; Ben-Omran, Tawfeg; Kumar, Pankaj; Kamel, Hussein; Ibrahim, Khalid; Mohamoud, Yasmin; Al-Dous, Eman; Al-Azwani, Iman; Malek, Joel A; Suhre, Karsten; Ross, M Elizabeth; Aleem, Alice Abdel

    2017-01-01

    Exome sequences account for only 2% of the genome and may overlook mutations causing disease. To obtain a more complete view, whole genome sequencing (WGS) was analyzed in a large consanguineous family in which members displayed autosomal recessively inherited cerebellar ataxia manifesting before 2 years of age. WGS from blood-derived genomic DNA was used for homozygosity mapping and a rare variant search. RNA from isolated blood leukocytes was used for quantitative polymerase chain reaction (PCR), RNA sequencing, and comparison of the transcriptomes of affected and unaffected family members. WGS revealed a point mutation in noncoding RNA RNU12 that was associated with early onset cerebellar ataxia. The U12-dependent minor spliceosome edits 879 known transcripts. Reverse transcriptase PCR demonstrated minor intron retention in all of 9 randomly selected RNAs from this group, and RNAseq showed splicing disruption specific to all U12-type introns detected in blood monocytes from affected individuals. Moreover, 144 minor intron-containing RNAs were differentially expressed, including transcripts for 3 genes previously associated with cerebellar neurodegeneration. Interference with particular spliceosome components, including small nuclear RNAs, cause reproducible uniquely distributed phenotypic and transcript-specific effects, making this an important category of disease-associated mutation. Our approach to differential expression analysis of minor intron-containing genes is applicable to other diseases involving altered transcriptome processing. ANN NEUROL 2017;81:68-78. © 2016 American Neurological Association.

  14. Heterozygous mutations in HSD17B4 cause juvenile peroxisomal D-bifunctional protein deficiency

    Science.gov (United States)

    Amor, David J.; Marsh, Ashley P.L.; Storey, Elsdon; Tankard, Rick; Gillies, Greta; Delatycki, Martin B.; Pope, Kate; Bromhead, Catherine; Leventer, Richard J.; Bahlo, Melanie

    2016-01-01

    Objective: To determine the genetic cause of slowly progressive cerebellar ataxia, sensorineural deafness, and hypergonadotropic hypogonadism in 5 patients from 3 different families. Methods: The patients comprised 2 sib pairs and 1 sporadic patient. Clinical assessment included history, physical examination, and brain MRI. Linkage analysis was performed separately on the 2 sets of sib pairs using single nucleotide polymorphism microarrays, followed by analysis of the intersection of the regions. Exome sequencing was performed on 1 affected patient with variant filtering and prioritization undertaken using these intersected regions. Results: Using a combination of sequencing technologies, we identified compound heterozygous mutations in HSD17B4 in all 5 affected patients. In all 3 families, peroxisomal D-bifunctional protein (DBP) deficiency was caused by compound heterozygosity for 1 nonsense/deletion mutation and 1 missense mutation. Conclusions: We describe 5 patients with juvenile DBP deficiency from 3 different families, bringing the total number of reported patients to 14, from 8 families. This report broadens and consolidates the phenotype associated with juvenile DBP deficiency.

  15. A Turkish family with Clouston syndrome caused by G11R mutation in GJB6

    Directory of Open Access Journals (Sweden)

    Zafer Yüksel

    2015-06-01

    Full Text Available Clouston Syndrome (CS is an ectodermal dyplasia characterized by nail dystrophy and hair defects and inherited in an autosomal dominant trait (OMIM #129500. It is caused by the mutations in GJB6 gene which is encoding connexin 30 (Cx30, a member of connexin family and included in the structure of gap junctions serving in intercellular interactions. In the present paper, a 30-year-old mother and her 3-year-old daughter diagnosed as CS. Seven more family members were also diagnosed as CS compatible with autosomal dominant trait. The disease causing heterozygous mutation c.31G>A (p.G11R was found by Sanger sequencing in exon 5 of GJB6. The latter mutation had been reported in several different populations yet it is reported for the first time in a Turkish family. Additionally, it is suggested that the history of cardiac conduction problems such as cardiac arrest and sinus bradycardia might be related with mutant Cx30.

  16. Homozygous ARHGEF2 mutation causes intellectual disability and midbrain-hindbrain malformation.

    Directory of Open Access Journals (Sweden)

    Ethiraj Ravindran

    2017-04-01

    Full Text Available Mid-hindbrain malformations can occur during embryogenesis through a disturbance of transient and localized gene expression patterns within these distinct brain structures. Rho guanine nucleotide exchange factor (ARHGEF family members are key for controlling the spatiotemporal activation of Rho GTPase, to modulate cytoskeleton dynamics, cell division, and cell migration. We identified, by means of whole exome sequencing, a homozygous frameshift mutation in the ARHGEF2 as a cause of intellectual disability, a midbrain-hindbrain malformation, and mild microcephaly in a consanguineous pedigree of Kurdish-Turkish descent. We show that loss of ARHGEF2 perturbs progenitor cell differentiation and that this is associated with a shift of mitotic spindle plane orientation, putatively favoring more symmetric divisions. The ARHGEF2 mutation leads to reduction in the activation of the RhoA/ROCK/MLC pathway crucial for cell migration. We demonstrate that the human brain malformation is recapitulated in Arhgef2 mutant mice and identify an aberrant migration of distinct components of the precerebellar system as a pathomechanism underlying the midbrain-hindbrain phenotype. Our results highlight the crucial function of ARHGEF2 in human brain development and identify a mutation in ARHGEF2 as novel cause of a neurodevelopmental disorder.

  17. UBIAD1 mutation alters a mitochondrial prenyltransferase to cause Schnyder corneal dystrophy.

    Directory of Open Access Journals (Sweden)

    Michael L Nickerson

    Full Text Available Mutations in a novel gene, UBIAD1, were recently found to cause the autosomal dominant eye disease Schnyder corneal dystrophy (SCD. SCD is characterized by an abnormal deposition of cholesterol and phospholipids in the cornea resulting in progressive corneal opacification and visual loss. We characterized lesions in the UBIAD1 gene in new SCD families and examined protein homology, localization, and structure.We characterized five novel mutations in the UBIAD1 gene in ten SCD families, including a first SCD family of Native American ethnicity. Examination of protein homology revealed that SCD altered amino acids which were highly conserved across species. Cell lines were established from patients including keratocytes obtained after corneal transplant surgery and lymphoblastoid cell lines from Epstein-Barr virus immortalized peripheral blood mononuclear cells. These were used to determine the subcellular localization of mutant and wild type protein, and to examine cholesterol metabolite ratios. Immunohistochemistry using antibodies specific for UBIAD1 protein in keratocytes revealed that both wild type and N102S protein were localized sub-cellularly to mitochondria. Analysis of cholesterol metabolites in patient cell line extracts showed no significant alteration in the presence of mutant protein indicating a potentially novel function of the UBIAD1 protein in cholesterol biochemistry. Molecular modeling was used to develop a model of human UBIAD1 protein in a membrane and revealed potentially critical roles for amino acids mutated in SCD. Potential primary and secondary substrate binding sites were identified and docking simulations indicated likely substrates including prenyl and phenolic molecules.Accumulating evidence from the SCD familial mutation spectrum, protein homology across species, and molecular modeling suggest that protein function is likely down-regulated by SCD mutations. Mitochondrial UBIAD1 protein appears to have a highly

  18. A GDF5 point mutation strikes twice--causing BDA1 and SYNS2.

    Directory of Open Access Journals (Sweden)

    Elisa Degenkolbe

    Full Text Available Growth and Differentiation Factor 5 (GDF5 is a secreted growth factor that belongs to the Bone Morphogenetic Protein (BMP family and plays a pivotal role during limb development. GDF5 is a susceptibility gene for osteoarthritis (OA and mutations in GDF5 are associated with a wide variety of skeletal malformations ranging from complex syndromes such as acromesomelic chondrodysplasias to isolated forms of brachydactylies or multiple synostoses syndrome 2 (SYNS2. Here, we report on a family with an autosomal dominant inherited combination of SYNS2 and additional brachydactyly type A1 (BDA1 caused by a single point mutation in GDF5 (p.W414R. Functional studies, including chondrogenesis assays with primary mesenchymal cells, luciferase reporter gene assays and Surface Plasmon Resonance analysis, of the GDF5(W414R variant in comparison to other GDF5 mutations associated with isolated BDA1 (p.R399C or SYNS2 (p.E491K revealed a dual pathomechanism characterized by a gain- and loss-of-function at the same time. On the one hand insensitivity to the main GDF5 antagonist NOGGIN (NOG leads to a GDF5 gain of function and subsequent SYNS2 phenotype. Whereas on the other hand, a reduced signaling activity, specifically via the BMP receptor type IA (BMPR1A, is likely responsible for the BDA1 phenotype. These results demonstrate that one mutation in the overlapping interface of antagonist and receptor binding site in GDF5 can lead to a GDF5 variant with pathophysiological relevance for both, BDA1 and SYNS2 development. Consequently, our study assembles another part of the molecular puzzle of how loss and gain of function mutations in GDF5 affect bone development in hands and feet resulting in specific types of brachydactyly and SYNS2. These novel insights into the biology of GDF5 might also provide further clues on the pathophysiology of OA.

  19. Mutations of the CEP290 gene encoding a centrosomal protein cause Meckel-Gruber syndrome.

    Science.gov (United States)

    Frank, Valeska; den Hollander, Anneke I; Brüchle, Nadina Ortiz; Zonneveld, Marijke N; Nürnberg, Gudrun; Becker, Christian; Du Bois, Gabriele; Kendziorra, Heide; Roosing, Susanne; Senderek, Jan; Nürnberg, Peter; Cremers, Frans P M; Zerres, Klaus; Bergmann, Carsten

    2008-01-01

    Meckel-Gruber syndrome (MKS) is an autosomal recessive, lethal multisystemic disorder characterized by meningooccipital encephalocele, cystic kidney dysplasia, hepatobiliary ductal plate malformation, and postaxial polydactyly. Recently, genes for MKS1 and MKS3 were identified, putting MKS on the list of ciliary disorders (ciliopathies). By positional cloning in a distantly related multiplex family, we mapped a novel locus for MKS to a 3-Mb interval on 12q21. Sequencing of the CEP290 gene located in the minimal critical region showed a homozygous 1-bp deletion supposed to lead to loss of function of the encoded centrosomal protein CEP290/nephrocystin-6. CEP290 is thought to be involved in chromosome segregation and localizes to cilia, centrosomes, and the nucleus. Subsequent analysis of another consanguineous multiplex family revealed homozygous haplotypes and the same frameshift mutation. Our findings add to the increasing body of evidence that ciliopathies can cause a broad spectrum of disease phenotypes, and pleiotropic effects of CEP290 mutations range from single organ involvement with isolated Leber congenital amaurosis to Joubert syndrome and lethal early embryonic multisystemic malformations in Meckel-Gruber syndrome. We compiled clinical and genetic data of all patients with CEP290 mutations described so far. No clear-cut genotype-phenotype correlations were apparent as almost all mutations are nonsense, frameshift, or splice-site changes and scattered throughout the gene irrespective of the patients' phenotypes. Conclusively, other factors than the type and location of CEP290 mutations may underlie phenotypic variability. (c) 2007 Wiley-Liss, Inc.

  20. De novo MEIS2 mutation causes syndromic developmental delay with persistent gastro-esophageal reflux.

    Science.gov (United States)

    Fujita, Atsushi; Isidor, Bertrand; Piloquet, Hugues; Corre, Pierre; Okamoto, Nobuhiko; Nakashima, Mitsuko; Tsurusaki, Yoshinori; Saitsu, Hirotomo; Miyake, Noriko; Matsumoto, Naomichi

    2016-09-01

    MEIS2 aberrations are considered to be the cause of intellectual disability, cleft palate and cardiac septal defect, as MEIS2 copy number variation is often observed with these phenotypes. To our knowledge, only one nucleotide-level change-specifically, an in-frame MEIS2 deletion-has so far been reported. Here, we report a female patient with a de novo nonsense mutation (c.611C>G, p.Ser204*) in MEIS2. She showed severe intellectual disability, moderate motor/verbal developmental delay, cleft palate, cardiac septal defect, hypermetropia, severe feeding difficulties with gastro-esophageal reflux and constipation. By reviewing this patient and previous patients with MEIS2 point mutations, we found that feeding difficulty with gastro-esophageal reflux appears to be one of the core clinical features of MEIS2 haploinsufficiency, in addition to intellectual disability, cleft palate and cardiac septal defect.

  1. The ataxia (axJ mutation causes abnormal GABAA receptor turnover in mice.

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    Corinna Lappe-Siefke

    2009-09-01

    Full Text Available Ataxia represents a pathological coordination failure that often involves functional disturbances in cerebellar circuits. Purkinje cells (PCs characterize the only output neurons of the cerebellar cortex and critically participate in regulating motor coordination. Although different genetic mutations are known that cause ataxia, little is known about the underlying cellular mechanisms. Here we show that a mutated ax(J gene locus, encoding the ubiquitin-specific protease 14 (Usp14, negatively influences synaptic receptor turnover. Ax(J mouse mutants, characterized by cerebellar ataxia, display both increased GABA(A receptor (GABA(AR levels at PC surface membranes accompanied by enlarged IPSCs. Accordingly, we identify physical interaction of Usp14 and the GABA(AR alpha1 subunit. Although other currently unknown changes might be involved, our data show that ubiquitin-dependent GABA(AR turnover at cerebellar synapses contributes to ax(J-mediated behavioural impairment.

  2. Mutations in the glucose-6-phosphatase gene that cause glycogen storage disease type 1a

    Energy Technology Data Exchange (ETDEWEB)

    Chou, J.Y.; Lei, K.J.; Shelly, L.L. [National Institutes of Health, Bethesda, MD (United States)

    1994-09-01

    Glycogen storage disease (GSD) type la (von Gierke disease) is caused by the deficiency of glucose-6-phosphatase (G6Pase), the key enzyme in glucose homeostasis. The disease presents with clinical manifestations of severe hypoglycemia, hepatomegaly, growth retardation, lactic acidemia, hyperlipidemia, and hyperuricemia. We have succeeded in isolating a murine G6Pase cDNA from a normal mouse liver cDNA library by differentially screening method. We then isolated the human G6Pase cDNA and gene. To date, we have characterized the G6Pase genes of twelve GSD type la patients and uncovered a total of six different mutations. The mutations are comprised of R83C (an Arg at codon 83 to a Cys), Q347X (a Gly at codon 347 to a stop codon), 459insTA (a two basepair insertion at nucleotide 459 yielding a truncated G6Pase of 129 residues), R295C (an Arg at codon 295 to a Cys), G222R (a Gly at codon 222 to an Arg) and {delta}F327 (a codon deletion for Phe-327 at nucleotides 1058 to 1060). The relative incidences of these mutations are 37.5% (R83C), 33.3% (Q347X), 16.6% (459insTA), 4.2% (G222R), 4.2% (R295C) and 4.2% ({delta}F327). Site-directed mutagenesis and transient expression assays demonstrated that the R83C, Q347X, R295C, and {delta}F327 mutations abolished whereas the G222R mutation greatly reduced G6Pase activity. We further characterized the structure-function requirements of amino acids 83, 222, and 295 in G6Pase catalysis. The identification of mutations in GSD type la patients has unequivocally established the molecular basis of the type la disorder. Knowledge of the mutations may be applied to prenatal diagnosis and opens the way for developing and evaluating new therapeutic approaches.

  3. Kufs disease, the major adult form of neuronal ceroid lipofuscinosis, caused by mutations in CLN6.

    LENUS (Irish Health Repository)

    Arsov, Todor

    2011-05-13

    The molecular basis of Kufs disease is unknown, whereas a series of genes accounting for most of the childhood-onset forms of neuronal ceroid lipofuscinosis (NCL) have been identified. Diagnosis of Kufs disease is difficult because the characteristic lipopigment is largely confined to neurons and can require a brain biopsy or autopsy for final diagnosis. We mapped four families with Kufs disease for whom there was good evidence of autosomal-recessive inheritance and found two peaks on chromosome 15. Three of the families were affected by Kufs type A disease and presented with progressive myoclonus epilepsy, and one was affected by type B (presenting with dementia and motor system dysfunction). Sequencing of a candidate gene in one peak shared by all four families identified no mutations, but sequencing of CLN6, found in the second peak and shared by only the three families affected by Kufs type A disease, revealed pathogenic mutations in all three families. We subsequently sequenced CLN6 in eight other families, three of which were affected by recessive Kufs type A disease. Mutations in both CLN6 alleles were found in the three type A cases and in one family affected by unclassified Kufs disease. Mutations in CLN6 are the major cause of recessive Kufs type A disease. The phenotypic differences between variant late-infantile NCL, previously found to be caused by CLN6, and Kufs type A disease are striking; there is a much later age at onset and lack of visual involvement in the latter. Sequencing of CLN6 will provide a simple diagnostic strategy in this disorder, in which definitive identification usually requires invasive biopsy.

  4. PIK3R1 Mutations Cause Syndromic Insulin Resistance with Lipoatrophy

    Science.gov (United States)

    Thauvin-Robinet, Christel; Auclair, Martine; Duplomb, Laurence; Caron-Debarle, Martine; Avila, Magali; St-Onge, Judith; Le Merrer, Martine; Le Luyer, Bernard; Héron, Delphine; Mathieu-Dramard, Michèle; Bitoun, Pierre; Petit, Jean-Michel; Odent, Sylvie; Amiel, Jeanne; Picot, Damien; Carmignac, Virginie; Thevenon, Julien; Callier, Patrick; Laville, Martine; Reznik, Yves; Fagour, Cédric; Nunes, Marie-Laure; Capeau, Jacqueline; Lascols, Olivier; Huet, Frédéric; Faivre, Laurence; Vigouroux, Corinne; Rivière, Jean-Baptiste

    2013-01-01

    Short stature, hyperextensibility of joints and/or inguinal hernia, ocular depression, Rieger anomaly, and teething delay (SHORT) syndrome is a developmental disorder with an unknown genetic cause and hallmarks that include insulin resistance and lack of subcutaneous fat. We ascertained two unrelated individuals with SHORT syndrome, hypothesized that the observed phenotype was most likely due to de novo mutations in the same gene, and performed whole-exome sequencing in the two probands and their unaffected parents. We then confirmed our initial observations in four other subjects with SHORT syndrome from three families, as well as 14 unrelated subjects presenting with syndromic insulin resistance and/or generalized lipoatrophy associated with dysmorphic features and growth retardation. Overall, we identified in nine affected individuals from eight families de novo or inherited PIK3R1 mutations, including a mutational hotspot (c.1945C>T [p.Arg649Trp]) present in four families. PIK3R1 encodes the p85α, p55α, and p50α regulatory subunits of class IA phosphatidylinositol 3 kinases (PI3Ks), which are known to play a key role in insulin signaling. Functional data from fibroblasts derived from individuals with PIK3R1 mutations showed severe insulin resistance for both proximal and distal PI3K-dependent signaling. Our findings extend the genetic causes of severe insulin-resistance syndromes and provide important information with respect to the function of PIK3R1 in normal development and its role in human diseases, including growth delay, Rieger anomaly and other ocular affections, insulin resistance, diabetes, paucity of fat, and ovarian cysts. PMID:23810378

  5. The R439C mutation in LMNA causes lamin oligomerization and susceptibility to oxidative stress

    Science.gov (United States)

    Verstraeten, Valerie LRM; Caputo, Sandrine; Van Steensel, Maurice AM; Duband-Goulet, Isabelle; Zinn-Justin, Sophie; Kamps, Miriam; Kuijpers, Helma JH; Östlund, Cecilia; Worman, Howard J; Briedé, Jacob J; Le Dour, Caroline; Marcelis, Carlo LM; Van Geel, Michel; Steijlen, Peter M; Van Den Wijngaard, Arthur; Ramaekers, Frans CS; Broers, Jos LV

    2009-01-01

    Abstract Dunnigan-type familial partial lipodystrophy (FPLD) is a laminopathy characterized by an aberrant fat distribution and a metabolic syndrome for which oxidative stress has recently been suggested as one of the disease-causing mechanisms. In a family affected with FPLD, we identified a heterozygous missense mutation c.1315C>T in the LMNA gene leading to the p.R439C substitution. Cultured patient fibroblasts do not show any prelamin A accumulation and reveal honeycomb-like lamin A/C formations in a significant percentage of nuclei. The mutation affects a region in the C-terminal globular domain of lamins A and C, different from the FPLD-related hot spot. Here, the introduction of an extra cysteine allows for the formation of disulphide-mediated lamin A/C oligomers. This oligomerization affects the interaction properties of the C-terminal domain with DNA as shown by gel retardation assays and causes a DNA-interaction pattern that is distinct from the classical R482W FPLD mutant. Particularly, whereas the R482W mutation decreases the binding efficiency of the C-terminal domain to DNA, the R439C mutation increases it. Electron spin resonance spectroscopy studies show significantly higher levels of reactive oxygen species (ROS) upon induction of oxidative stress in R439C patient fibroblasts compared to healthy controls. This increased sensitivity to oxidative stress seems independent of the oligomerization and enhanced DNA binding typical for R439C, as both the R439C and R482W mutants show a similar and significant increase in ROS upon induction of oxidative stress by H2O2. PMID:19220582

  6. HANAC Syndrome Col4a1 Mutation Causes Neonate Glomerular Hyperpermeability and Adult Glomerulocystic Kidney Disease.

    Science.gov (United States)

    Chen, Zhiyong; Migeon, Tiffany; Verpont, Marie-Christine; Zaidan, Mohamad; Sado, Yoshikazu; Kerjaschki, Dontscho; Ronco, Pierre; Plaisier, Emmanuelle

    2016-04-01

    Hereditary angiopathy, nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant syndrome caused by mutations in COL4A1 that encodes the α1 chain of collagen IV, a major component of basement membranes. Patients present with cerebral small vessel disease, retinal tortuosity, muscle cramps, and kidney disease consisting of multiple renal cysts, chronic kidney failure, and sometimes hematuria. Mutations producing HANAC syndrome localize within the integrin binding site containing CB3[IV] fragment of the COL4A1 protein. To investigate the pathophysiology of HANAC syndrome, we generated mice harboring the Col4a1 p.Gly498Val mutation identified in a family with the syndrome. Col4a1 G498V mutation resulted in delayed glomerulogenesis and podocyte differentiation without reduction of nephron number, causing albuminuria and hematuria in newborns. The glomerular defects resolved within the first month, but glomerular cysts developed in 3-month-old mutant mice. Abnormal structure of Bowman's capsule was associated with metalloproteinase induction and activation of the glomerular parietal epithelial cells that abnormally expressed CD44,α-SMA, ILK, and DDR1. Inflammatory infiltrates were observed around glomeruli and arterioles. Homozygous Col4a1 G498V mutant mice additionally showed dysmorphic papillae and urinary concentration defects. These results reveal a developmental role for the α1α1α2 collagen IV molecule in the embryonic glomerular basement membrane, affecting podocyte differentiation. The observed association between molecular alteration of the collagenous network in Bowman's capsule of the mature kidney and activation of parietal epithelial cells, matrix remodeling, and inflammation may account for glomerular cyst development and CKD in patients with COL4A1-related disorders.

  7. Charcot-Marie-Tooth type 4F disease caused by S399fsx410 mutation in the PRX gene.

    Science.gov (United States)

    Kabzinska, D; Drac, H; Sherman, D L; Kostera-Pruszczyk, A; Brophy, P J; Kochanski, A; Hausmanowa-Petrusewicz, I

    2006-03-14

    Charcot-Marie-Tooth type 4F disease (CMT4F) is an autosomal recessive neuropathy caused by mutations in the PRX gene. To date, only seven mutations have been identified in the PRX gene. In this study, the authors report a novel S399fsX410 mutation in the PRX gene and its effects at the protein level, which was identified in an 8-year-old patient with early-onset CMT disease.

  8. Hlf is a genetic modifier of epilepsy caused by voltage-gated sodium channel mutations.

    Science.gov (United States)

    Hawkins, Nicole A; Kearney, Jennifer A

    2016-01-01

    Mutations in voltage-gated sodium channel genes cause several types of human epilepsies. Often, individuals with the same sodium channel mutation exhibit diverse phenotypes. This suggests that factors beyond the primary mutation influence disease severity, including genetic modifiers. Mouse epilepsy models with voltage-gated sodium channel mutations exhibit strain-dependent phenotype variability, supporting a contribution of genetic modifiers in epilepsy. The Scn2a(Q54) (Q54) mouse model has a strain-dependent epilepsy phenotype. Q54 mice on the C57BL/6J (B6) strain exhibit delayed seizure onset and improved survival compared to [B6xSJL/J]F1.Q54 mice. We previously mapped two dominant modifier loci that influence Q54 seizure susceptibility and identified Hlf (hepatic leukemia factor) as a candidate modifier gene at one locus. Hlf and other PAR bZIP transcription factors had previously been associated with spontaneous seizures in mice thought to be caused by down-regulation of the pyridoxine pathway. An Hlf targeted knockout mouse model was used to evaluate the effect of Hlf deletion on Q54 phenotype severity. Hlf(KO/KO);Q54 double mutant mice exhibited elevated frequency and reduced survival compared to Q54 controls. To determine if direct modulation of the pyridoxine pathway could alter the Q54 phenotype, mice were maintained on a pyridoxine-deficient diet for 6 weeks. Dietary pyridoxine deficiency resulted in elevated seizure frequency and decreased survival in Q54 mice compared to control diet. To determine if Hlf could modify other epilepsies, Hlf(KO/+) mice were crossed with the Scn1a(KO/+) Dravet syndrome mouse model to examine the effect on premature lethality. Hlf(KO/+);Scn1a(KO/+) offspring exhibited decreased survival compared to Scn1a(KO/+) controls. Together these results demonstrate that Hlf is a genetic modifier of epilepsy caused by voltage-gated sodium channel mutations and that modulation of the pyridoxine pathway can also influence phenotype

  9. Mutations in two nonhomologous genes in a head-to-head configuration cause Ellis-van Creveld syndrome.

    NARCIS (Netherlands)

    Ruiz-Perez, V.L.; Tompson, S.W.; Blair, H.J.; Espinoza-Valdez, C.; Lapunzina, P.; Silva, E.O.; Hamel, B.C.J.; Gibbs, J.L.; Young, I.D.; Wright, M.J.; Goodship, J.A.

    2003-01-01

    Ellis-van Creveld syndrome (EvC) is an autosomal recessive skeletal dysplasia. Elsewhere, we described mutations in EVC in patients with this condition (Ruiz-Perez et al. 2000). We now report that mutations in EVC2 also cause EvC. These two genes lie in a head-to-head configuration that is conserved

  10. Molecular genetics and phenotypic characteristics of MODY caused by hepatocyte nuclear factor 4alpha mutations in a large European collection.

    NARCIS (Netherlands)

    Pearson, E.R.; Pruhova, S.; Tack, C.J.J.; Johansen, A.; Castleden, H.A.; Lumb, P.J.; Wierzbicki, A.S.; Clark, P.M.; Lebl, J.; Pedersen, O.; Ellard, S.; Hansen, T.; Hattersley, A.T.

    2005-01-01

    AIMS/HYPOTHESIS: Heterozygous mutations in the gene of the transcription factor hepatocyte nuclear factor 4alpha (HNF-4alpha) are considered a rare cause of MODY with only 14 mutations reported to date. The description of the phenotype is limited to single families. We investigated the genetics and

  11. Stickler syndrome caused by COL2A1 mutations: genotype-phenotype correlation in a series of 100 patients

    DEFF Research Database (Denmark)

    Hoornaert, Kristien P; Vereecke, Inge; Dewinter, Chantal;

    2010-01-01

    Stickler syndrome is an autosomal dominant connective tissue disorder caused by mutations in different collagen genes. The aim of our study was to define more precisely the phenotype and genotype of Stickler syndrome type 1 by investigating a large series of patients with a heterozygous mutation ...

  12. Generalized arterial calcification of infancy and pseudoxanthoma elasticum can be caused by mutations in either ENPP1 or ABCC6

    NARCIS (Netherlands)

    Nitschke, Y.; Baujat, G.; Botschen, U.; Wittkampf, T.; du Moulin, M.; Stella, J.; Merrer, M. le; Guest, G.; Lambot, K.; Tazarourte-Pinturier, M.F.; Chassaing, N.; Roche, O.; Feenstra, I.; Loechner, K.; Deshpande, C.; Garber, S.J.; Chikarmane, R.; Steinmann, B.; Shahinyan, T.; Martorell, L.; Davies, J.; Smith, W.E.; Kahler, S.G.; McCulloch, M.; Wraige, E.; Loidi, L.; Hohne, W.; Martin, L.; Hadj-Rabia, S.; Terkeltaub, R.; Rutsch, F.

    2012-01-01

    Spontaneous pathologic arterial calcifications in childhood can occur in generalized arterial calcification of infancy (GACI) or in pseudoxanthoma elasticum (PXE). GACI is associated with biallelic mutations in ENPP1 in the majority of cases, whereas mutations in ABCC6 are known to cause PXE.

  13. Case report: vitamin D-dependent rickets type 1 caused by a novel CYP27B1 mutation.

    Science.gov (United States)

    Füchtbauer, Laila; Brusgaard, Klaus; Ledaal, Pål; Frost, Morten; Frederiksen, Anja L

    2015-12-01

    Vitamin D-dependent rickets type 1 VDDR-1 is a recessive inherited disorder with impaired activation of vitamin D, caused by mutations in CYP27B1. We present long-time follow-up of a case with a novel mutation including high-resolution peripheral quantitative computed tomography of the bone. Adequate treatment resulted in a normalized phenotype.

  14. Generalized arterial calcification of infancy and pseudoxanthoma elasticum can be caused by mutations in either ENPP1 or ABCC6

    NARCIS (Netherlands)

    Nitschke, Y.; Baujat, G.; Botschen, U.; Wittkampf, T.; du Moulin, M.; Stella, J.; Merrer, M. le; Guest, G.; Lambot, K.; Tazarourte-Pinturier, M.F.; Chassaing, N.; Roche, O.; Feenstra, I.; Loechner, K.; Deshpande, C.; Garber, S.J.; Chikarmane, R.; Steinmann, B.; Shahinyan, T.; Martorell, L.; Davies, J.; Smith, W.E.; Kahler, S.G.; McCulloch, M.; Wraige, E.; Loidi, L.; Hohne, W.; Martin, L.; Hadj-Rabia, S.; Terkeltaub, R.; Rutsch, F.

    2012-01-01

    Spontaneous pathologic arterial calcifications in childhood can occur in generalized arterial calcification of infancy (GACI) or in pseudoxanthoma elasticum (PXE). GACI is associated with biallelic mutations in ENPP1 in the majority of cases, whereas mutations in ABCC6 are known to cause PXE. Howeve

  15. Recurrent and founder mutations in the Netherlands : mutation p.K217del in troponin T2, causing dilated cardiomyopathy

    NARCIS (Netherlands)

    Otten, E.; Deprez, R. H. Lekanne Dit; Weiss, M. M.; van Slegtenhorst, M.; Joosten, M.; van der Smagt, J. J.; Kerstjens-Frederikse, W. S.; Roofthooft, M. T. R.; Balk, A. H. M. M.; van den Berg, M. P.; van Tintelen, J. P.; Ruiter, J.S.; de Jonge, N.

    2010-01-01

    Background. About 30% of dilated cardiomyopathy (DCM) cases are familial. Mutations are mostly found in the genes encoding lanain A/C, beta-myosin heavy chain and the sarcomeric protein cardiac troponin-T (TNNT2). Mutations in TNNT2 are reported in approximately 3% of DCM patients. The overall pheno

  16. ISPD gene mutations are a common cause of congenital and limb-girdle muscular dystrophies.

    Science.gov (United States)

    Cirak, Sebahattin; Foley, Aileen Reghan; Herrmann, Ralf; Willer, Tobias; Yau, Shu; Stevens, Elizabeth; Torelli, Silvia; Brodd, Lina; Kamynina, Alisa; Vondracek, Petr; Roper, Helen; Longman, Cheryl; Korinthenberg, Rudolf; Marrosu, Gianni; Nürnberg, Peter; Michele, Daniel E; Plagnol, Vincent; Hurles, Matt; Moore, Steven A; Sewry, Caroline A; Campbell, Kevin P; Voit, Thomas; Muntoni, Francesco

    2013-01-01

    Dystroglycanopathies are a clinically and genetically diverse group of recessively inherited conditions ranging from the most severe of the congenital muscular dystrophies, Walker-Warburg syndrome, to mild forms of adult-onset limb-girdle muscular dystrophy. Their hallmark is a reduction in the functional glycosylation of α-dystroglycan, which can be detected in muscle biopsies. An important part of this glycosylation is a unique O-mannosylation, essential for the interaction of α-dystroglycan with extracellular matrix proteins such as laminin-α2. Mutations in eight genes coding for proteins in the glycosylation pathway are responsible for ∼50% of dystroglycanopathy cases. Despite multiple efforts using traditional positional cloning, the causative genes for unsolved dystroglycanopathy cases have escaped discovery for several years. In a recent collaborative study, we discovered that loss-of-function recessive mutations in a novel gene, called isoprenoid synthase domain containing (ISPD), are a relatively common cause of Walker-Warburg syndrome. In this article, we report the involvement of the ISPD gene in milder dystroglycanopathy phenotypes ranging from congenital muscular dystrophy to limb-girdle muscular dystrophy and identified allelic ISPD variants in nine cases belonging to seven families. In two ambulant cases, there was evidence of structural brain involvement, whereas in seven, the clinical manifestation was restricted to a dystrophic skeletal muscle phenotype. Although the function of ISPD in mammals is not yet known, mutations in this gene clearly lead to a reduction in the functional glycosylation of α-dystroglycan, which not only causes the severe Walker-Warburg syndrome but is also a common cause of the milder forms of dystroglycanopathy.

  17. Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome.

    Science.gov (United States)

    Ü Basmanav, F Buket; Cau, Laura; Tafazzoli, Aylar; Méchin, Marie-Claire; Wolf, Sabrina; Romano, Maria Teresa; Valentin, Frederic; Wiegmann, Henning; Huchenq, Anne; Kandil, Rima; Garcia Bartels, Natalie; Kilic, Arzu; George, Susannah; Ralser, Damian J; Bergner, Stefan; Ferguson, David J P; Oprisoreanu, Ana-Maria; Wehner, Maria; Thiele, Holger; Altmüller, Janine; Nürnberg, Peter; Swan, Daniel; Houniet, Darren; Büchner, Aline; Weibel, Lisa; Wagner, Nicola; Grimalt, Ramon; Bygum, Anette; Serre, Guy; Blume-Peytavi, Ulrike; Sprecher, Eli; Schoch, Susanne; Oji, Vinzenz; Hamm, Henning; Farrant, Paul; Simon, Michel; Betz, Regina C

    2016-12-01

    Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant to being combed flat. Until now, both simplex and familial UHS-affected case subjects with autosomal-dominant as well as -recessive inheritance have been reported. However, none of these case subjects were linked to a molecular genetic cause. Here, we report the identification of UHS-causative mutations located in the three genes PADI3 (peptidylarginine deiminase 3), TGM3 (transglutaminase 3), and TCHH (trichohyalin) in a total of 11 children. All of these individuals carry homozygous or compound heterozygous mutations in one of these three genes, indicating an autosomal-recessive inheritance pattern in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic causes of UHS and shed light on its pathophysiology and hair physiology in general. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  18. De Novo ACTA2 Mutation Causes a Novel Syndrome of Multisystemic Smooth Muscle Dysfunction

    Science.gov (United States)

    Milewicz, Dianna M.; Østergaard, John R.; Ala-Kokko, Leena M.; Khan, Nadia; Grange, Dorothy K.; Mendoza-Londono, Roberto; Bradley, Timothy J.; Olney, Ann Haskins; Adès, Lesley; Maher, Joseph F.; Guo, Dongchuan; Buja, L. Maximilian; Kim, Dong; Hyland, James C.; Regalado, Ellen S.

    2011-01-01

    Smooth muscle cells (SMCs) contract to perform many physiological functions, including regulation of blood flow and pressure in arteries, contraction of the pupils, peristalsis of the gut and voiding of the bladder. SMC lineage in these organs is characterized by cellular expression of the SMC isoform of α-actin, encoded by the ACTA2 gene. We report here on a unique and de novo mutation in ACTA2, R179H, that causes a syndrome characterized by dysfunction of SMCs throughout the body, leading to aortic and cerebrovascular disease, fixed dilated pupils, hypotonic bladder, malrotation and hypoperistalsis of the gut and pulmonary hypertension. PMID:20734336

  19. De novo mutations in Plxnd1 and Rev3l cause mobius syndrome

    OpenAIRE

    Kayserili Karabey, Hülya; Tomas-Roca, Laura; Tsaalbi-Shtylik, Anastasia; Jansen, Jacob G.; Singh, Manvendra K.; Epstein, Jonathan A.; Altunoglu, Umut; Verzijl, Harriette; Soria, Laura; van Beusekom, Ellen; Roscioli, Tony; Iqbal, Zafar; Gilissen, Christian; Hoischen, Alexander; de Brouwer,Arjan P. M.; Erasmus, Corrie; Schubert, Dirk; Brunner, Han; Aytes, Antonio Perez; Marin, Faustino; Aroca, Pilar; Carta, Arturo; de Wind, Niels; Padberg, George W.; van Bokhoven, Hans

    2015-01-01

    ARTICLE Received 15 Nov 2014 | Accepted 17 Apr 2015 | Published 12 Jun 2015 De novo mutations in PLXND1 and REV3L cause Mo¨bius syndrome Laura Tomas-Roca1,2, Anastasia Tsaalbi-Shtylik3, Jacob G. Jansen3, Manvendra K. Singh4,5, Jonathan A. Epstein4, Umut Altunoglu6, Harriette Verzijl7, Laura Soria1, Ellen van Beusekom1, Tony Roscioli1,8, Zafar Iqbal1, Christian Gilissen1, Alexander Hoischen9, Arjan P.M. de Brouwer1, Corrie Erasmus7, Dirk Schubert10, Han Brunner1,11, Antoni...

  20. Mutations in c10orf11, a melanocyte-differentiation gene, cause autosomal-recessive albinism

    DEFF Research Database (Denmark)

    Grønskov, Karen; Dooley, Christopher M; Østergaard, Elsebet

    2013-01-01

    in an individual originating from Lithuania. Immunohistochemistry showed localization of C10orf11 in melanoblasts and melanocytes in human fetal tissue, but no localization was seen in retinal pigment epithelial cells. Knockdown of the zebrafish (Danio rerio) homolog with the use of morpholinos resulted...... in substantially decreased pigmentation and a reduction of the apparent number of pigmented melanocytes. The morphant phenotype was rescued by wild-type C10orf11, but not by mutant C10orf11. In conclusion, we have identified a melanocyte-differentiation gene, C10orf11, which when mutated causes autosomal...

  1. Mutations of LRTOMT, a fusion gene with alternative reading frames, cause nonsyndromic deafness in humans

    OpenAIRE

    Ahmed, Zubair M.; Masmoudi, Saber; Kalay, Ersan; Belyantseva, Inna A.; Mosrati, Mohamed Ali; Collin, Rob W. J.; Riazuddin, Saima; Hmani-Aifa, Mounira; Venselaar, Hanka; Kawar, Mayya N; Abdelaziz, Tlili; van der Zwaag, Bert; Khan, Shahid Y.; Ayadi, Leila; Riazuddin, S. Amer

    2008-01-01

    Many proteins necessary for sound transduction have been discovered through positional cloning of genes that cause deafness 1–3 . In this study, we report that mutations of LRTOMT are associated with profound non-syndromic hearing loss at the DFNB63 locus on human chromosome 11q13.3-q13.4. LRTOMT has two alternative reading frames and encodes two different proteins, LRTOMT1 and LRTOMT2, that are detected by Western blot analyses. LRTOMT2 is a putative methyltransferase. During evolution, nove...

  2. Estimation of Mutation Frequencies of Mice Caused by Radiation -- Application of LDM Model I

    CERN Document Server

    Manabe, Yuichiro

    2012-01-01

    In a separate paper [Y. Manabe et al: arxiv:1204.2324], we propose a mathematical model to estimate biological damage caused by radiation, which we call LDM (Low Dose Meeting) Model, hereafter. By using LDM model, we calculate the mutation frequency of mice and compare our results with the existing data, the frequency of transmitted specific-locus mutations induced in mouse spermatogonia stem-cells, which was reported by Russell and Kelly [W. L. Russell. et al: Proc. Natl. Acad. Sci. USA 79 (1982), 542-544]. By fixing the two parameters of LDM model, c and {\\mu}, we can reproduce the observed data almost well. They are determined by experimental value of mutation frequency together with the corresponding total dose and dose rate. For a moment, we had to adopt simple assumption due to the lack of detailed information. If we have information of the exposure process exactly, it is easy to estimate the dose-rate effectiveness factor (DDREF) almost exactly. Thus LDM model may be applied to total dose and dose rate...

  3. Novel TCAP mutation c.32C>A causing limb girdle muscular dystrophy 2G.

    Directory of Open Access Journals (Sweden)

    Amirtharaj Francis

    Full Text Available TCAP encoded telethonin is a 19 kDa protein, which plays an important role in anchoring titin in Z disc of the sarcomere, and is known to cause LGMD2G, a rare muscle disorder characterised by proximal and distal lower limb weakness, calf hypertrophy and loss of ambulation. A total of 300 individuals with ARLGMD were recruited for this study. Among these we identified 8 clinically well characterised LGMD2G cases from 7 unrelated Dravidian families. Clinical examination revealed predominantly proximo-distal form of weakness, scapular winging, muscle atrophy, calf hypertrophy and foot drop, immunoblot showed either complete absence or severe reduction of telethonin. Genetic analysis revealed a novel nonsense homozygous mutation c.32C>A, p.(Ser11* in three patients of a consanguineous family and an 8 bp homozygous duplication c.26_33dupAGGTGTCG, p.(Arg12fs31* in another patient. Both mutations possibly lead to truncated protein or nonsense mediated decay. We could not find any functionally significant TCAP mutation in the remaining 6 samples, except for two other polymorphisms, c.453A>C, p.( =  and c.-178G>T, which were found in cases and controls. This is the first report from India to demonstrate TCAP association with LGMD2G.

  4. Loss-of-function mutations in the gene encoding filaggrin cause ichthyosis vulgaris.

    Science.gov (United States)

    Smith, Frances J D; Irvine, Alan D; Terron-Kwiatkowski, Ana; Sandilands, Aileen; Campbell, Linda E; Zhao, Yiwei; Liao, Haihui; Evans, Alan T; Goudie, David R; Lewis-Jones, Sue; Arseculeratne, Gehan; Munro, Colin S; Sergeant, Ann; O'Regan, Gráinne; Bale, Sherri J; Compton, John G; DiGiovanna, John J; Presland, Richard B; Fleckman, Philip; McLean, W H Irwin

    2006-03-01

    Ichthyosis vulgaris (OMIM 146700) is the most common inherited disorder of keratinization and one of the most frequent single-gene disorders in humans. The most widely cited incidence figure is 1 in 250 based on a survey of 6,051 healthy English schoolchildren. We have identified homozygous or compound heterozygous mutations R501X and 2282del4 in the gene encoding filaggrin (FLG) as the cause of moderate or severe ichthyosis vulgaris in 15 kindreds. In addition, these mutations are semidominant; heterozygotes show a very mild phenotype with incomplete penetrance. The mutations show a combined allele frequency of approximately 4% in populations of European ancestry, explaining the high incidence of ichthyosis vulgaris. Profilaggrin is the major protein of keratohyalin granules in the epidermis. During terminal differentiation, it is cleaved into multiple filaggrin peptides that aggregate keratin filaments. The resultant matrix is cross-linked to form a major component of the cornified cell envelope. We find that loss or reduction of this major structural protein leads to varying degrees of impaired keratinization.

  5. ANO10 mutations cause ataxia and coenzyme Q₁₀ deficiency.

    Science.gov (United States)

    Balreira, Andrea; Boczonadi, Veronika; Barca, Emanuele; Pyle, Angela; Bansagi, Boglarka; Appleton, Marie; Graham, Claire; Hargreaves, Iain P; Rasic, Vedrana Milic; Lochmüller, Hanns; Griffin, Helen; Taylor, Robert W; Naini, Ali; Chinnery, Patrick F; Hirano, Michio; Quinzii, Catarina M; Horvath, Rita

    2014-11-01

    Inherited ataxias are heterogeneous disorders affecting both children and adults, with over 40 different causative genes, making molecular genetic diagnosis challenging. Although recent advances in next-generation sequencing have significantly improved mutation detection, few treatments exist for patients with inherited ataxia. In two patients with adult-onset cerebellar ataxia and coenzyme Q10 (CoQ10) deficiency in muscle, whole exome sequencing revealed mutations in ANO10, which encodes anoctamin 10, a member of a family of putative calcium-activated chloride channels, and the causative gene for autosomal recessive spinocerebellar ataxia-10 (SCAR10). Both patients presented with slowly progressive ataxia and dysarthria leading to severe disability in the sixth decade. Epilepsy and learning difficulties were also present in one patient, while retinal degeneration and cataract were present in the other. The detection of mutations in ANO10 in our patients indicate that ANO10 defects cause secondary low CoQ10 and SCAR10 patients may benefit from CoQ10 supplementation.

  6. A novel mutation causing mild, atypical fumarylacetoacetase deficiency (Tyrosinemia type I: a case report

    Directory of Open Access Journals (Sweden)

    Kvittingen Eli-Anne

    2009-12-01

    Full Text Available Abstract A male patient, born to unrelated Belgian parents, presented at 4 months with epistaxis, haematemesis and haematochezia. On physical examination he presented petechiae and haematomas, and a slightly enlarged liver. Serum transaminases were elevated to 5-10 times upper limit of normal, alkaline phosphatases were 1685 U/L (180 s ( Fumarylacetoacetase (FAH protein and activity in cultured fibroblasts and liver tissue were decreased but not absent. 4-hydroxyphenylpyruvate dioxygenase activity in liver was normal, which is atypical for tyrosinemia type I. A novel mutation was found in the FAH gene: c.103G>A (Ala35Thr. In vitro expression studies showed this mutation results in a strongly decreased FAH protein expression. Dietary treatment with phenylalanine and tyrosine restriction was initiated at 4 months, leading to complete clinical and biochemical normalisation. The patient, currently aged 12 years, shows a normal physical and psychomotor development. This is the first report of mild tyrosinemia type I disease caused by an Ala35Thr mutation in the FAH gene, presenting atypically without increase of the diagnostically important toxic metabolites succinylacetone and succinylacetoacetate.

  7. GBA2 Mutations Cause a Marinesco-Sjögren-Like Syndrome: Genetic and Biochemical Studies

    Science.gov (United States)

    Haugarvoll, Kristoffer; Johansson, Stefan; Rodriguez, Carlos E.; Boman, Helge; Haukanes, Bjørn Ivar; Bruland, Ove; Roque, Francisco; Jonassen, Inge; Blomqvist, Maria; Telstad, Wenche; Månsson, Jan-Eric

    2017-01-01

    Background With the advent new sequencing technologies, we now have the tools to understand the phenotypic diversity and the common occurrence of phenocopies. We used these techniques to investigate two Norwegian families with an autosomal recessive cerebellar ataxia with cataracts and mental retardation. Methods and Results Single nucleotide polymorphism (SNP) chip analysis followed by Exome sequencing identified a 2 bp homozygous deletion in GBA2 in both families, c.1528_1529del [p.Met510Valfs*17]. Furthermore, we report the biochemical characterization of GBA2 in these patients. Our studies show that a reduced activity of GBA2 is sufficient to elevate the levels of glucosylceramide to similar levels as seen in Gaucher disease. Furthermore, leucocytes seem to be the proper enzyme source for in vitro analysis of GBA2 activity. Conclusions We report GBA2 mutations causing a Marinesco-Sjögren-like syndrome in two Norwegian families. One of the families was originally diagnosed with Marinesco-Sjögren syndrome based on an autosomal recessive cerebellar ataxia with cataracts and mental retardation. Our findings highlight the phenotypic variability associated with GBA2 mutations, and suggest that patients with Marinesco-Sjögren-like syndromes should be tested for mutations in this gene. PMID:28052128

  8. A novel mutation in the HCN4 gene causes symptomatic sinus bradycardia in Moroccan Jews.

    Science.gov (United States)

    Laish-Farkash, Avishag; Glikson, Michael; Brass, Dovrat; Marek-Yagel, Dina; Pras, Elon; Dascal, Nathan; Antzelevitch, Charles; Nof, Eyal; Reznik, Haya; Eldar, Michael; Luria, David

    2010-12-01

    to conduct a clinical, genetic, and functional analysis of 3 unrelated families with familial sinus bradycardia (FSB). mutations in the hyperpolarization-activated nucleotide-gated channel (HCN4) are known to be associated with FSB. three males of Moroccan Jewish descent were hospitalized: 1 survived an out-of-hospital cardiac arrest and 2 presented with weakness and presyncopal events. All 3 had significant sinus bradycardia, also found in other first-degree relatives, with a segregation suggesting autosomal-dominant inheritance. All had normal response to exercise and normal heart structure. Sequencing of the HCN4 gene in all patients revealed a C to T transition at nucleotide position 1,454, which resulted in an alanine to valine change (A485V) in the ion channel pore found in most of their bradycardiac relatives, but not in 150 controls. Functional expression of the mutated ion channel in Xenopus oocytes and in human embryonic kidney 293 cells revealed profoundly reduced function and synthesis of the mutant channel compared to wild-type. we describe a new mutation in the HCN4 gene causing symptomatic FSB in 3 unrelated individuals of similar ethnic background that may indicate unexplained FSB in this ethnic group. This profound functional defect is consistent with the symptomatic phenotype.

  9. An inactivating mutation in the SOD 1 gene causes familial amyotrophic lateral sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Pramatarova, A.; Rouleau, G.A. [Montreal General Hospital Research Institute (Canada); Goto, J. [Univ. of Tokyo (Japan)] [and others

    1994-09-01

    Amyotrophic lateral sclerosis (ALS) is characterized by highly selective death of large motor neurons in the cerebral cortex and spinal cord. The familial form of ALS (FALS) accounts for approximately 10% of the cases and is transmitted in an autosomal dominant manner. Recently the defective gene causing chromosome 21-linked FALS was shown to be the Cu/Zn superoxide dismutase (SOD 1). However, the precise mechanism of neurotoxicity seen in FALS with SOD 1 mutations is still unknown. Until now all SOD 1 mutations reported were single base pair substitutions (missense). We have identified a nonsense mutation in exon 5 of the SOD 1 gene in a FALS kindred. This two base pair deletion provokes a frameshift and a predicted premature truncation of the protein. The region affected has a very important structural and functional role: it contains part of the active loop and is involved in dimer contact. We would predict that the loss of these structures would impair the functioning of the enzyme.

  10. Mutations in TAX1BP3 cause dilated cardiomyopathy with septo-optic dysplasia.

    Science.gov (United States)

    Reinstein, Eyal; Orvin, Katia; Tayeb-Fligelman, Einav; Stiebel-Kalish, Hadas; Tzur, Shay; Pimienta, Allen L; Bazak, Lily; Bengal, Tuvia; Cohen, Lior; Gaton, Dan D; Bormans, Concetta; Landau, Meytal; Kornowski, Ran; Shohat, Mordechai; Behar, Doron M

    2015-04-01

    We describe a Bedouin family with a novel autosomal recessive syndrome characterized by dilated cardiomyopathy and septo-optic dysplasia. Genetic analysis revealed a homozygous missense mutation in TAX1BP3, which encodes a small PDZ domain containing protein implicated in regulation of the Wnt/β-catenin signaling pathway, as the causative mutation. The mutation affects a conserved residue located at the core of TAX1BP3 binding pocket and is predicted to impair the nature of a crucial hydrophobic patch, thereby interrupting the structure and stability of the protein, and its ability to interact with other proteins. TAX1BP3 is highly expressed in heart and brain and consistent with the clinical findings observed in our patients; a knockdown of TAX1BP3 causes elongation defects, enlarged pericard, and enlarged head structures in zebrafish embryos. Thus, we describe a new genetic disorder that expands the monogenic cardiomyopathy disease spectrum and suggests that TAX1BP3 is essential for heart and brain development.

  11. A CHRNE frameshift mutation causes congenital myasthenic syndrome in young Jack Russell Terriers.

    Science.gov (United States)

    Rinz, Caitlin J; Lennon, Vanda A; James, Fiona; Thoreson, James B; Tsai, Kate L; Starr-Moss, Alison N; Humphries, H Dale; Guo, Ling T; Palmer, Anthony C; Clark, Leigh Anne; Shelton, G Diane

    2015-12-01

    Congenital myasthenic syndromes (CMSs) are a group of rare genetic disorders of the neuromuscular junction resulting in structural or functional causes of fatigable weakness that usually begins early in life. Mutations in pre-synaptic, synaptic and post-synaptic proteins have been demonstrated in human cases, with more than half involving aberrations in nicotinic acetylcholine receptor (AChR) subunits. CMS was first recognized in dogs in 1974 as an autosomal recessive trait in Jack Russell Terriers (JRTs). A deficiency of junctional AChRs was demonstrated. Here we characterize a CMS in 2 contemporary cases of JRT littermates with classic clinical and electromyographic findings, and immunochemical confirmation of an approximately 90% reduction in AChR protein content. Loci encoding the 5 AChR subunits were evaluated using microsatellite markers, and CHRNB1 and CHRNE were identified as candidate genes. Sequences of the splice sites and exons of both genes revealed a single base insertion in exon 7 of CHRNE that predicts a frameshift mutation and a premature stop codon. We further demonstrated this pathogenic mutation in CHRNE in archival tissues from unrelated JRTs studied 34 years ago.

  12. Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success.

    Science.gov (United States)

    Jacobson, Samuel G; Aleman, Tomas S; Cideciyan, Artur V; Sumaroka, Alexander; Schwartz, Sharon B; Windsor, Elizabeth A M; Traboulsi, Elias I; Heon, Elise; Pittler, Steven J; Milam, Ann H; Maguire, Albert M; Palczewski, Krzysztof; Stone, Edwin M; Bennett, Jean

    2005-04-26

    Mutations in RPE65, a gene essential to normal operation of the visual (retinoid) cycle, cause the childhood blindness known as Leber congenital amaurosis (LCA). Retinal gene therapy restores vision to blind canine and murine models of LCA. Gene therapy in blind humans with LCA from RPE65 mutations may also have potential for success but only if the retinal photoreceptor layer is intact, as in the early-disease stage-treated animals. Here, we use high-resolution in vivo microscopy to quantify photoreceptor layer thickness in the human disease to define the relationship of retinal structure to vision and determine the potential for gene therapy success. The normally cone photoreceptor-rich central retina and rod-rich regions were studied. Despite severely reduced cone vision, many RPE65-mutant retinas had near-normal central microstructure. Absent rod vision was associated with a detectable but thinned photoreceptor layer. We asked whether abnormally thinned RPE65-mutant retina with photoreceptor loss would respond to treatment. Gene therapy in Rpe65(-/-) mice at advanced-disease stages, a more faithful mimic of the humans we studied, showed success but only in animals with better-preserved photoreceptor structure. The results indicate that identifying and then targeting retinal locations with retained photoreceptors will be a prerequisite for successful gene therapy in humans with RPE65 mutations and in other retinal degenerative disorders now moving from proof-of-concept studies toward clinical trials.

  13. Mutations in DONSON disrupt replication fork stability and cause microcephalic dwarfism.

    Science.gov (United States)

    Reynolds, John J; Bicknell, Louise S; Carroll, Paula; Higgs, Martin R; Shaheen, Ranad; Murray, Jennie E; Papadopoulos, Dimitrios K; Leitch, Andrea; Murina, Olga; Tarnauskaitė, Žygimantė; Wessel, Sarah R; Zlatanou, Anastasia; Vernet, Audrey; von Kriegsheim, Alex; Mottram, Rachel M A; Logan, Clare V; Bye, Hannah; Li, Yun; Brean, Alexander; Maddirevula, Sateesh; Challis, Rachel C; Skouloudaki, Kassiani; Almoisheer, Agaadir; Alsaif, Hessa S; Amar, Ariella; Prescott, Natalie J; Bober, Michael B; Duker, Angela; Faqeih, Eissa; Seidahmed, Mohammed Zain; Al Tala, Saeed; Alswaid, Abdulrahman; Ahmed, Saleem; Al-Aama, Jumana Yousuf; Altmüller, Janine; Al Balwi, Mohammed; Brady, Angela F; Chessa, Luciana; Cox, Helen; Fischetto, Rita; Heller, Raoul; Henderson, Bertram D; Hobson, Emma; Nürnberg, Peter; Percin, E Ferda; Peron, Angela; Spaccini, Luigina; Quigley, Alan J; Thakur, Seema; Wise, Carol A; Yoon, Grace; Alnemer, Maha; Tomancak, Pavel; Yigit, Gökhan; Taylor, A Malcolm R; Reijns, Martin A M; Simpson, Michael A; Cortez, David; Alkuraya, Fowzan S; Mathew, Christopher G; Jackson, Andrew P; Stewart, Grant S

    2017-04-01

    To ensure efficient genome duplication, cells have evolved numerous factors that promote unperturbed DNA replication and protect, repair and restart damaged forks. Here we identify downstream neighbor of SON (DONSON) as a novel fork protection factor and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a replisome component that stabilizes forks during genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATM- and Rad3-related (ATR)-dependent signaling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity and the potentiation of chromosomal instability. Hypomorphic mutations in DONSON substantially reduce DONSON protein levels and impair fork stability in cells from patients, consistent with defective DNA replication underlying the disease phenotype. In summary, we have identified mutations in DONSON as a common cause of microcephalic dwarfism and established DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.

  14. Phenotypic Variability of Osteogenesis Imperfecta Type V Caused by an IFITM5 Mutation

    Science.gov (United States)

    Shapiro, Jay R; Lietman, Caressa; Grover, Monica; Lu, James T; Nagamani, Sandesh CS; Dawson, Brian C; Baldridge, Dustin M; Bainbridge, Matthew N; Cohn, Dan H; Blazo, Maria; Roberts, Timothy T; Brennen, Feng-Shu; Wu, Yimei; Gibbs, Richard A; Melvin, Pamela; Campeau, Philippe M; Lee, Brendan H

    2013-01-01

    In a large cohort of osteogenesis imperfecta type V (OI type V) patients (17 individuals from 12 families), we identified the same mutation in the 5′ untranslated region (5′UTR) of the interferon-induced transmembrane protein 5 (IFITM5) gene by whole exome and Sanger sequencing (IFITM5 c.–14C > T) and provide a detailed description of their phenotype. This mutation leads to the creation of a novel start codon adding five residues to IFITM5 and was recently reported in several other OI type V families. The variability of the phenotype was quite large even within families. Whereas some patients presented with the typical calcification of the forearm interosseous membrane, radial head dislocation and hyperplastic callus (HPC) formation following fractures, others had only some of the typical OI type V findings. Thirteen had calcification of interosseous membranes, 14 had radial head dislocations, 10 had HPC, 9 had long bone bowing, 11 could ambulate without assistance, and 1 had mild unilateral mixed hearing loss. The bone mineral density varied greatly, even within families. Our study thus highlights the phenotypic variability of OI type V caused by the IFITM5 mutation. PMID:23408678

  15. Parietal lobe deficits in frontotemporal lobar degeneration caused by a mutation in the progranulin gene.

    Science.gov (United States)

    Rohrer, Jonathan D; Warren, Jason D; Omar, Rohani; Mead, Simon; Beck, Jonathan; Revesz, Tamas; Holton, Janice; Stevens, John M; Al-Sarraj, Safa; Pickering-Brown, Stuart M; Hardy, John; Fox, Nick C; Collinge, John; Warrington, Elizabeth K; Rossor, Martin N

    2008-04-01

    To describe the clinical, neuropsychologic, and radiologic features of a family with a C31LfsX35 mutation in the progranulin gene CCDS11483.1). Case series. A large British kindred (DRC255) with a PGRN mutation was assessed. Affected individuals presented with a mean age of 57.8 years (range, 54-67 years) and a mean disease duration of 6.1 years (range, 2-11 years). All patients exhibited a clinical and radiologic phenotype compatible with frontotemporal lobar degeneration based on current consensus criteria. However, unlike sporadic frontotemporal lobar degeneration, parietal deficits, consisting of dyscalculia, visuoperceptual /visuospatial dysfunction, and/or limb apraxia, were a common feature, and brain imaging showed posterior extension of frontotemporal atrophy to involve the parietal lobes. Other common clinical features included language output impairment with either dynamic aphasia or nonfluent aphasia and a behavioral syndrome dominated by apathy. We suggest that parietal deficits may be a prominent feature of PGRN mutations and that these deficits may be caused by disruption of frontoparietal functional pathways.

  16. Mouse H6 Homeobox 1 (Hmx1 mutations cause cranial abnormalities and reduced body mass

    Directory of Open Access Journals (Sweden)

    Munroe Robert J

    2009-04-01

    involvement. Additionally, these mutant Hmx1 alleles represent the first mouse models of a recently-discovered Oculo-Auricular syndrome caused by mutation of the orthologous human gene.

  17. Molecular insights on pathogenic effects of mutations causing phosphoglycerate kinase deficiency.

    Directory of Open Access Journals (Sweden)

    Laurent R Chiarelli

    Full Text Available Phosphoglycerate kinase (PGK catalyzes an important ATP-generating step in glycolysis. PGK1 deficiency is an uncommon X-linked inherited disorder, generally characterized by various combinations of non-spherocytic hemolytic anemia, neurological dysfunctions, and myopathies. Patients rarely exhibit all three clinical features. To provide a molecular framework to the different pathological manifestations, all known mutations were reviewed and 16 mutant enzymes, obtained as recombinant forms, were functionally and structurally characterized. Most mutations heavily affect thermal stability and to a different extent catalytic efficiency, in line with the remarkably low PGK activity clinically observed in the patients. Mutations grossly impairing protein stability, but moderately affecting kinetic properties (p.I47N, p.L89P, p.C316R, p.S320N, and p.A354P present the most homogeneous correlation with the clinical phenotype. Patients carrying these mutations display hemolytic anemia and neurological disorders, and,except for p.A354P variant, no myopaty. Variants highly perturbed in both catalytic efficiency (p.G158V, p.D164V, p.K191del, D285V, p.D315N, and p.T378P and heat stability (all, but p.T378P result to be mainly associated with myopathy alone. Finally, mutations faintly affecting molecular properties (p.R206P, p.E252A, p.I253T, p.V266M, and p.D268N correlate with a wide spectrum of clinical symptoms. These are the first studies that correlate the clinical symptoms with the molecular properties of the mutant enzymes. All findings indicate that the different clinical manifestations associated with PGK1 deficiency chiefly depend on the distinctive type of perturbations caused by mutations in the PGK1 gene, highlighting the need for determination of the molecular properties of PGK variants to assist in prognosis and genetic counseling. However, the clinical symptoms can not be understood only on the bases of molecular properties of the mutant enzyme

  18. Identification of a novel mutation in hereditary vitamin D resistant rickets causing exon skipping.

    Science.gov (United States)

    Hawa, N S; Cockerill, F J; Vadher, S; Hewison, M; Rut, A R; Pike, J W; O'Riordan, J L; Farrow, S M

    1996-07-01

    Hereditary vitamin D resistant rickets (HVDRR) is an autosomal recessive disorder resulting in target organ resistance to the actions of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In many cases, this disorder has been shown to be due to mutations in the gene encoding vitamin D receptors (VDR). In a patient with characteristic features of this disorder, we investigated the functional defect and sequenced the coding region of the gene for mutations. Skin fibroblasts from patient and control were used to measure binding of 1,25(OH)2D3 and functional responses to the hormone. These cells were also used to prepare RNA from which cDNA was prepared and sequenced. Furthermore, genomic DNA was prepared from the fibroblasts and the intron/exon boundaries sequenced. A child with classic features of HVDRR with alopecia diagnosed as having rickets due to resistance to 1,25(OH)2D3. Nuclear association of 1,25(OH)2D3 was determined in patient and control cells and the functional response to 1,25(OH)2D3 was assessed by measurement of 25-hydroxyvitamin D-24-hydroxylase(24-hydroxylase) activity. VDR cDNA and genomic DNA prepared from patient and control cells were sequenced. Cells from the patient with HVDRR had undetectable amounts of VDR compared to control cells and did not show induction of 24-hydroxylase activity following treatment with 1,25(OH)2D3. Sequencing of the VDR coding region after RT-PCR of RNA revealed an absence of exon 4 in patient RNA which was not due to a deletion in genomic DNA but was caused by exon skipping during RNA processing. In addition, the deletion of exon 4 sequences from RNA leads to a frameshift in translation resulting in a premature stop codon. Amplification of genomic DNA around the intron/exon boundary of exon 4 revealed a point mutation in the 5' donor splice site of intron 4. In this study, we have identified a novel mutation in the gene for vitamin D receptors in a patient with the characteristic phenotype of hereditary vitamin D resistant

  19. Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse.

    Science.gov (United States)

    Boudko, Sergei P; Ishikawa, Yoshihiro; Lerch, Thomas F; Nix, Jay; Chapman, Michael S; Bächinger, Hans Peter

    2012-11-08

    Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B. The crystal structures of both wild-type and mutated (Gly6->Arg) horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid. Interactions of the mutated cyclophilin B with a set of endoplasmic reticulum-resident proteins must be affected.

  20. Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse

    Directory of Open Access Journals (Sweden)

    Boudko Sergei P

    2012-11-01

    Full Text Available Abstract Background Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B. Results The crystal structures of both wild-type and mutated (Gly6->Arg horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid. Conclusions Interactions of the mutated cyclophilin B with a set of endoplasmic reticulum-resident proteins must be affected.

  1. Mutations of mitochondrial DNA polymerase gammaA are a frequent cause of autosomal dominant or recessive progressive external ophthalmoplegia.

    Science.gov (United States)

    Lamantea, Eleonora; Tiranti, Valeria; Bordoni, Andreina; Toscano, Antonio; Bono, Francesco; Servidei, Serena; Papadimitriou, Alex; Spelbrink, Hans; Silvestri, Laura; Casari, Giorgio; Comi, Giacomo P; Zeviani, Massimo

    2002-08-01

    One form of familial progressive external ophthalmoplegia with multiple mitochondrial DNA deletions recently has been associated with mutations in POLG1, the gene encoding pol gammaA, the catalytic subunit of mitochondrial DNA polymerase. We screened the POLG1 gene in several PEO families and identified five different heterozygous missense mutations of POLG1 in 10 autosomal dominant families. Recessive mutations were found in three families. Our data show that mutations of POLG1 are the most frequent cause of familial progressive external ophthalmoplegia associated with accumulation of multiple mitochondrial DNA deletions, accounting for approximately 45% of our family cohort.

  2. CCDC65 mutation causes primary ciliary dyskinesia with normal ultrastructure and hyperkinetic cilia.

    Directory of Open Access Journals (Sweden)

    Amjad Horani

    Full Text Available BACKGROUND: Primary ciliary dyskinesia (PCD is a genetic disorder characterized by impaired ciliary function, leading to chronic sinopulmonary disease. The genetic causes of PCD are still evolving, while the diagnosis is often dependent on finding a ciliary ultrastructural abnormality and immotile cilia. Here we report a novel gene associated with PCD but without ciliary ultrastructural abnormalities evident by transmission electron microscopy, but with dyskinetic cilia beating. METHODS: Genetic linkage analysis was performed in a family with a PCD subject. Gene expression was studied in Chlamydomonas reinhardtii and human airway epithelial cells, using RNA assays and immunostaining. The phenotypic effects of candidate gene mutations were determined in primary culture human tracheobronchial epithelial cells transduced with gene targeted shRNA sequences. Video-microscopy was used to evaluate cilia motion. RESULTS: A single novel mutation in CCDC65, which created a termination codon at position 293, was identified in a subject with typical clinical features of PCD. CCDC65, an orthologue of the Chlamydomonas nexin-dynein regulatory complex protein DRC2, was localized to the cilia of normal nasal epithelial cells but was absent in those from the proband. CCDC65 expression was up-regulated during ciliogenesis in cultured airway epithelial cells, as was DRC2 in C. reinhardtii following deflagellation. Nasal epithelial cells from the affected individual and CCDC65-specific shRNA transduced normal airway epithelial cells had stiff and dyskinetic cilia beating patterns compared to control cells. Moreover, Gas8, a nexin-dynein regulatory complex component previously identified to associate with CCDC65, was absent in airway cells from the PCD subject and CCDC65-silenced cells. CONCLUSION: Mutation in CCDC65, a nexin-dynein regulatory complex member, resulted in a frameshift mutation and PCD. The affected individual had altered cilia beating patterns, and

  3. Fen1 mutations that specifically disrupt its interaction with PCNA cause aneuploidy-associated cancer

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Sankar Mitra; Qin Huang; Kemp H Kernstine; Gerd P Pfeifer; Binghui Shen; Huifang Dai; Muralidhar L Hegde; Mian Zhou; Zhigang Guo; Xiwei Wu; Jun WU; Lei Su; Xueyan Zhong

    2011-01-01

    DNA replication and repair are critical processes for all living organisms to ensure faithful duplication and transmission of genetic information. Flap endonuclease 1 (Feni), a structure-specific nuclease, plays an important role in multiple DNA metabolic pathways and maintenance of genome stability. Human FEN1 mutations that impair its exonuclease activity have been linked to cancer development. FEN1 interacts with multiple proteins, including proliferation cell nuclear antigen (PCNA), to form various functional complexes. Interactions with these proteins are considered to be the key molecular mechanisms mediating FEN1's key biological functions. The current challenge is to experimentally demonstrate the biological consequence of a specific interaction without compromising other functions of a desired protein. To address this issue, we established a mutant mouse model harboring a FEN1 point mutation (F343A/F344A, FFAA), which specifically abolishes the FEN1/PCNA interaction. We show that the FFAA mutation causes defects in RNA primer removal and long-patch base excision repair, even in the heterozygous state, resulting in numerous DNA breaks. These breaks activate the G2/M checkpoint protein, Chk1, and induce neartetraploid aneuploidy, commonly observed in human cancer, consequently elevating the transformation frequency. Consistent with this, inhibition of aneupioidy formation by a Chk1 inhibitor significantly suppressed the cellular transformation. WT/FFAA FEN1 mutant mice develop aneuploidy-associated cancer at a high frequency. Thus, this study establishes an exemplary case for investigating the biological significance of protein-protein interactions by knock-in of a point mutation rather than knock-out of a whole gene.

  4. Mutations in APOPT1, encoding a mitochondrial protein, cause cavitating leukoencephalopathy with cytochrome c oxidase deficiency.

    Science.gov (United States)

    Melchionda, Laura; Haack, Tobias B; Hardy, Steven; Abbink, Truus E M; Fernandez-Vizarra, Erika; Lamantea, Eleonora; Marchet, Silvia; Morandi, Lucia; Moggio, Maurizio; Carrozzo, Rosalba; Torraco, Alessandra; Diodato, Daria; Strom, Tim M; Meitinger, Thomas; Tekturk, Pinar; Yapici, Zuhal; Al-Murshedi, Fathiya; Stevens, René; Rodenburg, Richard J; Lamperti, Costanza; Ardissone, Anna; Moroni, Isabella; Uziel, Graziella; Prokisch, Holger; Taylor, Robert W; Bertini, Enrico; van der Knaap, Marjo S; Ghezzi, Daniele; Zeviani, Massimo

    2014-09-04

    Cytochrome c oxidase (COX) deficiency is a frequent biochemical abnormality in mitochondrial disorders, but a large fraction of cases remains genetically undetermined. Whole-exome sequencing led to the identification of APOPT1 mutations in two Italian sisters and in a third Turkish individual presenting severe COX deficiency. All three subjects presented a distinctive brain MRI pattern characterized by cavitating leukodystrophy, predominantly in the posterior region of the cerebral hemispheres. We then found APOPT1 mutations in three additional unrelated children, selected on the basis of these particular MRI features. All identified mutations predicted the synthesis of severely damaged protein variants. The clinical features of the six subjects varied widely from acute neurometabolic decompensation in late infancy to subtle neurological signs, which appeared in adolescence; all presented a chronic, long-surviving clinical course. We showed that APOPT1 is targeted to and localized within mitochondria by an N-terminal mitochondrial targeting sequence that is eventually cleaved off from the mature protein. We then showed that APOPT1 is virtually absent in fibroblasts cultured in standard conditions, but its levels increase by inhibiting the proteasome or after oxidative challenge. Mutant fibroblasts showed reduced amount of COX holocomplex and higher levels of reactive oxygen species, which both shifted toward control values by expressing a recombinant, wild-type APOPT1 cDNA. The shRNA-mediated knockdown of APOPT1 in myoblasts and fibroblasts caused dramatic decrease in cell viability. APOPT1 mutations are responsible for infantile or childhood-onset mitochondrial disease, hallmarked by the combination of profound COX deficiency with a distinctive neuroimaging presentation.

  5. N370S-GBA1 mutation causes lysosomal cholesterol accumulation in Parkinson's disease.

    Science.gov (United States)

    García-Sanz, Patricia; Orgaz, Lorena; Bueno-Gil, Guillermo; Espadas, Isabel; Rodríguez-Traver, Eva; Kulisevsky, Jaime; Gutierrez, Antonia; Dávila, José C; González-Polo, Rosa A; Fuentes, José M; Mir, Pablo; Vicario, Carlos; Moratalla, Rosario

    2017-08-05

    Heterozygous mutations in the GBA1 gene, which encodes the lysosomal enzyme β-glucocerebrosidase-1, increase the risk of developing Parkinson's disease, although the underlying mechanisms remain unclear. The aim of this study was to explore the impact of the N370S-GBA1 mutation on cellular homeostasis and vulnerability in a patient-specific cellular model of PD. We isolated fibroblasts from 4 PD patients carrying the N370S/wild type GBA1 mutation and 6 controls to study the autophagy-lysosome pathway, endoplasmic reticulum stress, and Golgi apparatus structure by Western blot, immunofluorescence, LysoTracker and Filipin stainings, mRNA analysis, and electron microscopy. We evaluated cell vulnerability by apoptosis, reactive oxygen species and mitochondrial membrane potential with flow cytometry. The N370S mutation produced a significant reduction in β-glucocerebrosidase-1 protein and enzyme activity and β-glucocerebrosidase-1 retention within the endoplasmic reticulum, which interrupted its traffic to the lysosome. This led to endoplasmic reticulum stress activation and triggered unfolded protein response and Golgi apparatus fragmentation. Furthermore, these alterations resulted in autophagosome and p62/SQSTM1 accumulation. This impaired autophagy was a result of dysfunctional lysosomes, indicated by multilamellar body accumulation probably caused by increased cholesterol, enlarged lysosomal mass, and reduced enzyme activity. This phenotype impaired the removal of damaged mitochondria and reactive oxygen species production and enhanced cell death. Our results support a connection between the loss of β-glucocerebrosidase-1 function, cholesterol accumulation, and the disruption of cellular homeostasis in GBA1-PD. Our work reveals new insights into the cellular pathways underlying PD pathogenesis, providing evidence that GBA1-PD shares common features with lipid-storage diseases. © 2017 International Parkinson and Movement Disorder Society. © 2017 International

  6. ALS-associated mutation FUS-R521C causes DNA damage and RNA splicing defects.

    Science.gov (United States)

    Qiu, Haiyan; Lee, Sebum; Shang, Yulei; Wang, Wen-Yuan; Au, Kin Fai; Kamiya, Sherry; Barmada, Sami J; Finkbeiner, Steven; Lui, Hansen; Carlton, Caitlin E; Tang, Amy A; Oldham, Michael C; Wang, Hejia; Shorter, James; Filiano, Anthony J; Roberson, Erik D; Tourtellotte, Warren G; Chen, Bin; Tsai, Li-Huei; Huang, Eric J

    2014-03-01

    Autosomal dominant mutations of the RNA/DNA binding protein FUS are linked to familial amyotrophic lateral sclerosis (FALS); however, it is not clear how FUS mutations cause neurodegeneration. Using transgenic mice expressing a common FALS-associated FUS mutation (FUS-R521C mice), we found that mutant FUS proteins formed a stable complex with WT FUS proteins and interfered with the normal interactions between FUS and histone deacetylase 1 (HDAC1). Consequently, FUS-R521C mice exhibited evidence of DNA damage as well as profound dendritic and synaptic phenotypes in brain and spinal cord. To provide insights into these defects, we screened neural genes for nucleotide oxidation and identified brain-derived neurotrophic factor (Bdnf) as a target of FUS-R521C-associated DNA damage and RNA splicing defects in mice. Compared with WT FUS, mutant FUS-R521C proteins formed a more stable complex with Bdnf RNA in electrophoretic mobility shift assays. Stabilization of the FUS/Bdnf RNA complex contributed to Bdnf splicing defects and impaired BDNF signaling through receptor TrkB. Exogenous BDNF only partially restored dendrite phenotype in FUS-R521C neurons, suggesting that BDNF-independent mechanisms may contribute to the defects in these neurons. Indeed, RNA-seq analyses of FUS-R521C spinal cords revealed additional transcription and splicing defects in genes that regulate dendritic growth and synaptic functions. Together, our results provide insight into how gain-of-function FUS mutations affect critical neuronal functions.

  7. A Novel Homozygous Mutation in FOXC1 Causes Axenfeld Rieger Syndrome with Congenital Glaucoma.

    Directory of Open Access Journals (Sweden)

    Shazia Micheal

    Full Text Available Anterior segment dysgenesis (ASD disorders are a group of clinically and genetically heterogeneous phenotypes in which frequently cornea, iris, and lens are affected. This study aimed to identify novel mutations in PAX6, PITX2 and FOXC1 in families with anterior segment dysgenesis disorders.We studied 14 Pakistani and one Mexican family with Axenfeld Rieger syndrome (ARS; n = 10 or aniridia (n = 5. All affected and unaffected family members underwent full ophthalmologic and general examinations. Total genomic DNA was isolated from peripheral blood. PCR and Sanger sequencing were performed for the exons and intron-exon boundaries of the FOXC1, PAX6, and PITX2 genes.Mutations were identified in five of the 15 probands; four variants were novel and one variant was described previously. A novel de novo variant (c.225C>A; p.Tyr75* was identified in the PAX6 gene in two unrelated probands with aniridia. In addition, a known variant (c.649C>T; p.Arg217* in PAX6 segregated in a family with aniridia. In the FOXC1 gene, a novel heterozygous variant (c.454T>C; p.Trp152Arg segregated with the disease in a Mexican family with ARS. A novel homozygous variant (c.92_100del; p.Ala31_Ala33del in the FOXC1 gene segregated in a Pakistani family with ARS and congenital glaucoma.Our study expands the mutation spectrum of the PAX6 and FOXC1 genes in individuals with anterior segment dysgenesis disorders. In addition, our study suggests that FOXC1 mutations, besides typical autosomal dominant ARS, can also cause ARS with congenital glaucoma through an autosomal recessive inheritance pattern. Our results thus expand the disease spectrum of FOXC1, and may lead to a better understanding of the role of FOXC1 in development.

  8. Angiotensin I-converting enzyme mutation (Trp1197Stop causes a dramatic increase in blood ACE.

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    Andrew B Nesterovitch

    Full Text Available BACKGROUND: Angiotensin-converting enzyme (ACE metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling. Elevated ACE levels may be associated with an increased risk for different cardiovascular or respiratory diseases, including asthma. Previously, a molecular mechanism underlying a 5-fold familial increase of blood ACE was discovered: Pro1199Leu substitution enhanced the cleavage-secretion process. Carriers of this mutation were Caucasians from Europe (mostly Dutch or had European roots. METHODOLOGY/PRINCIPAL FINDINGS: We have found a family of African-American descent whose affected members' blood ACE level was increased 13-fold over normal. In affected family members, codon TGG coding for Trp1197 was substituted in one allele by TGA (stop codon. As a result, half of ACE expressed in these individuals had a length of 1196 amino acids and lacked a transmembrane anchor. This ACE mutant is not trafficked to the cell membrane and is directly secreted out of cells; this mechanism apparently accounts for the high serum ACE level seen in affected individuals. A haplotype of the mutant ACE allele was determined based on 12 polymorphisms, which may help to identify other carriers of this mutation. Some but not all carriers of this mutation demonstrated airflow obstruction, and some but not all have hypertension. CONCLUSIONS/SIGNIFICANCE: We have identified a novel Trp1197Stop mutation that results in dramatic elevation of serum ACE. Since blood ACE elevation is often taken as a marker of disease activity (sarcoidosis and Gaucher diseases, it is important for clinicians and medical scientists to be aware of alternative genetic causes of elevated blood ACE that are not apparently linked to disease.

  9. Highly prevalent LIPH founder mutations causing autosomal recessive woolly hair/hypotrichosis in Japan and the genotype/phenotype correlations.

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    Kana Tanahashi

    Full Text Available Mutations in LIPH cause of autosomal recessive woolly hair/hypotrichosis (ARWH, and the 2 missense mutations c.736T>A (p.Cys246Ser and c.742C>A (p.His248Asn are considered prevalent founder mutations for ARWH in the Japanese population. To reveal genotype/phenotype correlations in ARWH cases in Japan and the haplotypes in 14 Japanese patients from 14 unrelated Japanese families. 13 patients had woolly hair, and 1 patient had complete baldness since birth. An LIPH mutation search revealed homozygous c.736T>A mutations in 10 of the patients. Compound heterozygous c.736T>A and c.742C>A mutations were found in 3 of the patients, and homozygous c.742C>A mutation in 1 patient. The phenotype of mild hypotrichosis with woolly hair was restricted to the patients with the homozygous c.736T>A mutation. The severe phenotype of complete baldness was seen in only 1 patient with homozygous c.742C>A. Haplotype analysis revealed that the alleles containing the LIPH c.736T>A mutation had a haplotype identical to that reported previously, although 4 alleles out of 5 chromosomes containing the LIPH c.742C>A mutation had a different haplotype from the previously reported founder allele. These alleles with c.742C>A are thought to be the third founder LIPH mutation causing ARWH. To accurately determine the prevalence of the founder mutations, we investigated allele frequencies of those mutations in 819 Japanese controls. Heterozygous c.736T>A mutations were found in 13 controls (allele frequency: 0.0079; carrier rate: 0.016, and heterozygous c.742C>A mutations were found in 2 controls (allele frequency: 0.0012; carrier rate: 0.0024. In conclusion, this study confirms the more accurate allele frequencies of the pathogenic founder mutations of LIPH and shows that there is a third founder mutation in Japan. In addition, the present findings suggest that the mutation patterns of LIPH might be associated with hypotrichosis severity in ARWH.

  10. Early Bolting in Short Days: An Arabidopsis Mutation That Causes Early Flowering and Partially Suppresses the Floral Phenotype of leafy

    National Research Council Canada - National Science Library

    Concepción Gómez-Mena; Manuel Piñeiro; José M. Franco-Zorrilla; Julio Salinas; George Coupland; José M. Martínez-Zapater

    2001-01-01

    .... Some of these signals promote the onset of flowering, whereas others repress it. We describe here the isolation and characterization of two allelic mutations that cause early flowering and define a new locus, EARLY BOLTING IN SHORT DAYS (EBS...

  11. Targeting Mitogen-Activated Protein Kinase Signaling in Mouse Models of Cardiomyopathy Caused by Lamin A/C Gene Mutations.

    Science.gov (United States)

    Muchir, Antoine; Worman, Howard J

    2016-01-01

    The most frequently occurring mutations in the gene encoding nuclear lamin A and nuclear lamin C cause striated muscle diseases virtually always involving the heart. In this review, we describe the approaches and methods used to discover that cardiomyopathy-causing lamin A/C gene mutations increase MAP kinase signaling in the heart and that this plays a role in disease pathogenesis. We review different mouse models of cardiomyopathy caused by lamin A/C gene mutations and how transcriptomic analysis of one model identified increased cardiac activity of the ERK1/2, JNK, and p38α MAP kinases. We describe methods used to measure the activity of these MAP kinases in mouse hearts and then discuss preclinical treatment protocols using pharmacological inhibitors to demonstrate their role in pathogenesis. Several of these kinase inhibitors are in clinical development and could potentially be used to treat human subjects with cardiomyopathy caused by lamin A/C gene mutations.

  12. A novel mutation in the ADA gene causing severe combined immunodeficiency in an Arab patient: a case report

    Directory of Open Access Journals (Sweden)

    Hellani Ali

    2009-04-01

    Full Text Available Abstract Introduction About 20% of the cases of human severe combined immunodeficiency are the result of the child being homozygous for defective genes encoding the enzyme adenosine deaminase. To our knowledge, the mutation pattern in Arab patients with severe combined immunodeficiency has never been reported previously. Case presentation A 14-month-old Arab boy had clinical features typical of severe combined immunodeficiency. His clinical picture and flow cytometric analysis raised the diagnosis of adenosine deaminase deficiency and prompted us to screen the adenosine deaminase gene for mutation(s. We detected a novel mutation in exon 9 of the adenosine deaminase gene (p.Arg282>Gln, which we believe is the cause of the severe combined immunodeficiency phenotype observed in our patient. Conclusion This is the first report of adenosine deaminase mutation in an Arab patient with severe combined immunodeficiency due to a novel pathogenic mutation in the adenosine deaminase gene.

  13. Novel association of neurofibromatosis type 1-causing mutations in families with neurofibromatosis-Noonan syndrome.

    Science.gov (United States)

    Ekvall, Sara; Sjörs, Kerstin; Jonzon, Anders; Vihinen, Mauno; Annerén, Göran; Bondeson, Marie-Louise

    2014-03-01

    Neurofibromatosis-Noonan syndrome (NFNS) is a rare condition with clinical features of both neurofibromatosis type 1 (NF1) and Noonan syndrome (NS). All three syndromes belong to the RASopathies, which are caused by dysregulation of the RAS-MAPK pathway. The major gene involved in NFNS is NF1, but co-occurring NF1 and PTPN11 mutations in NFNS have been reported. Knowledge about possible involvement of additional RASopathy-associated genes in NFNS is, however, very limited. We present a comprehensive clinical and molecular analysis of eight affected individuals from three unrelated families displaying features of NF1 and NFNS. The genetic etiology of the clinical phenotypes was investigated by mutation analysis, including NF1, PTPN11, SOS1, KRAS, NRAS, BRAF, RAF1, SHOC2, SPRED1, MAP2K1, MAP2K2, and CBL. All three families harbored a heterozygous NF1 variant, where the first family had a missense variant, c.5425C>T;p.R1809C, the second family a recurrent 4bp-deletion, c.6789_6792delTTAC;p.Y2264Tfs*6, and the third family a splice-site variant, c.2991-1G>A, resulting in skipping of exon 18 and an in-frame deletion of 41 amino acids. These NF1 variants have all previously been reported in NF1 patients. Surprisingly, both c.6789_6792delTTAC and c.2991-1G>A are frequently associated with NF1, but association to NFNS has, to our knowledge, not previously been reported. Our results support the notion that NFNS represents a variant of NF1, genetically distinct from NS, and is caused by mutations in NF1, some of which also cause classical NF1. Due to phenotypic overlap between NFNS and NS, we propose screening for NF1 mutations in NS patients, preferentially when café-au-lait spots are present. © 2013 Wiley Periodicals, Inc.

  14. Protein causes hyperinsulinemia: a Chinese patient with hyperinsulinism/hyperammonaemia syndrome due to a glutamate dehydrogenase gene mutation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shi; XIAO Xin-hua; DIAO Cheng-ming; TONG An-li; WANG Ou; QIU Zheng-qing; YU Kang; WANG Tong

    2010-01-01

    @@ Glucose is derived from three sources: intestinal absorption, glycogenolysis, and gluconeogenesis. Hypoglycemia in child is often attributed to depletion of glycogen stores. However, recently, congenital hyperinsulinism becomes an important cause of hypoglycaemia in early infancy. Mutations in the genes encoding SUR1 and KIR6.2 are the most frequent genetic causes of hyperinsulinism followed by mutations in the glutamate dehydrogenase (GDH) gene which encodes hyperinsulinism/hyperammonaemia (HI/HA) syndrome.

  15. A homozygous mutation in TRIM36 causes autosomal recessive anencephaly in an Indian family.

    Science.gov (United States)

    Singh, Nivedita; Kumble Bhat, Vishwanath; Tiwari, Ankana; Kodaganur, Srinivas G; Tontanahal, Sagar J; Sarda, Astha; Malini, K V; Kumar, Arun

    2017-01-13

    Anencephaly is characterized by the absence of brain tissues and cranium. During primary neurulation stage of the embryo, the rostral part of the neural pore fails to close, leading to anencephaly. Anencephaly shows a heterogeneous etiology, ranging from environmental to genetic causes. The autosomal recessive inheritance of anencephaly has been reported in several populations. In this study, we employed whole-exome sequencing and identified a homozygous missense mutation c.1522C>A (p.Pro508Thr) in the TRIM36 gene as the cause of autosomal recessive anencephaly (APH) in an Indian family. The TRIM36 gene is expressed in the developing brain, suggesting a role in neurogenesis. In silco analysis showed that proline at codon position 508 is highly conserved in 26 vertebrate species, and the mutation is predicted to affect the conformation of the B30.2/SPRY domain of TRIM36. Both in vitro and in vivo results showed that the mutation renders the TRIM36 protein less stable. TRIM36 is known to associate with microtubules. Transient expression of the mutant TRIM36 in HeLa and LN229 cells resulted in microtubule disruption, disorganized spindles, loosely arranged chromosomes, multiple spindles, abnormal cytokinesis, reduced cell proliferation and increased apoptosis as compared to cells transfected with its wild-type counterpart. The siRNA knock down of TRIM36 in HeLa and LN229 cells also led to reduced cell proliferation and increased apoptosis. We suggest that microtubule disruption and disorganized spindles mediated by mutant TRIM36 affect neural cell proliferation during neural tube formation, leading to anencephaly.

  16. A Founder Mutation in VPS11 Causes an Autosomal Recessive Leukoencephalopathy Linked to Autophagic Defects

    Science.gov (United States)

    Schaffner, Adam; Fedick, Anastasia; Kaye, Lauren E.; Liao, Jun; Yachelevich, Naomi; Chu, Mary-Lynn; Boles, Richard G.; Moran, Ellen; Tokita, Mari; Gorman, Elizabeth; Zhang, Wei; Xia, Fan; Leduc, Magalie; Yang, Yaping; Eng, Christine; Wong, Lee-Jun; Schiffmann, Raphael; Diaz, George A.; Kornreich, Ruth; Thummel, Ryan; Wasserstein, Melissa; Yue, Zhenyu; Edelmann, Lisa

    2016-01-01

    Genetic leukoencephalopathies (gLEs) are a group of heterogeneous disorders with white matter abnormalities affecting the central nervous system (CNS). The causative mutation in ~50% of gLEs is unknown. Using whole exome sequencing (WES), we identified homozygosity for a missense variant, VPS11: c.2536T>G (p.C846G), as the genetic cause of a leukoencephalopathy syndrome in five individuals from three unrelated Ashkenazi Jewish (AJ) families. All five patients exhibited highly concordant disease progression characterized by infantile onset leukoencephalopathy with brain white matter abnormalities, severe motor impairment, cortical blindness, intellectual disability, and seizures. The carrier frequency of the VPS11: c.2536T>G variant is 1:250 in the AJ population (n = 2,026). VPS11 protein is a core component of HOPS (homotypic fusion and protein sorting) and CORVET (class C core vacuole/endosome tethering) protein complexes involved in membrane trafficking and fusion of the lysosomes and endosomes. The cysteine 846 resides in an evolutionarily conserved cysteine-rich RING-H2 domain in carboxyl terminal regions of VPS11 proteins. Our data shows that the C846G mutation causes aberrant ubiquitination and accelerated turnover of VPS11 protein as well as compromised VPS11-VPS18 complex assembly, suggesting a loss of function in the mutant protein. Reduced VPS11 expression leads to an impaired autophagic activity in human cells. Importantly, zebrafish harboring a vps11 mutation with truncated RING-H2 domain demonstrated a significant reduction in CNS myelination following extensive neuronal death in the hindbrain and midbrain. Thus, our study reveals a defect in VPS11 as the underlying etiology for an autosomal recessive leukoencephalopathy disorder associated with a dysfunctional autophagy-lysosome trafficking pathway. PMID:27120463

  17. A stop codon mutation in SCN9A causes lack of pain sensation.

    Science.gov (United States)

    Ahmad, Sultan; Dahllund, Leif; Eriksson, Anders B; Hellgren, Dennis; Karlsson, Urban; Lund, Per-Eric; Meijer, Inge A; Meury, Luc; Mills, Tracy; Moody, Adrian; Morinville, Anne; Morten, John; O'donnell, Dajan; Raynoschek, Carina; Salter, Hugh; Rouleau, Guy A; Krupp, Johannes J

    2007-09-01

    The general lack of pain experience is a rare occurrence in humans, and the molecular causes for this phenotype are not well understood. Here we have studied a Canadian family from Newfoundland with members who exhibit a congenital inability to experience pain. We have mapped the locus to a 13.7 Mb region on chromosome 2q (2q24.3-2q31.1). Screening of candidate genes in this region identified a protein-truncating mutation in SCN9A, which encodes for the voltage-gated sodium channel Na(v)1.7. The mutation is a C-A transversion at nucleotide 984 transforming the codon for tyrosine 328 to a stop codon. The predicted product lacks all pore-forming regions of Na(v)1.7. Indeed, expression of this altered gene in a cell line did not produce functional responses, nor did it cause compensatory effects on endogenous voltage-gated sodium currents when expressed in ND7/23 cells. Because a homozygous knockout of Na(v)1.7 in mice has been shown to be lethal, we explored why a deficiency of Na(v)1.7 is non-lethal in humans. Expression studies in monkey, human, mouse and rat tissue indicated species-differences in the Na(v)1.7 expression profile. Whereas in rodents the channel was strongly expressed in hypothalamic nuclei, only weak mRNA levels were detected in this area in primates. Furthermore, primate pituitary and adrenal glands were devoid of signal, whereas these two glands were mRNA-positive in rodents. This species difference may explain the non-lethality of the observed mutation in humans. Our data further establish Na(v)1.7 as a critical element of peripheral nociception in humans.

  18. FAM20A mutations can cause enamel-renal syndrome (ERS.

    Directory of Open Access Journals (Sweden)

    Shih-Kai Wang

    Full Text Available Enamel-renal syndrome (ERS is an autosomal recessive disorder characterized by severe enamel hypoplasia, failed tooth eruption, intrapulpal calcifications, enlarged gingiva, and nephrocalcinosis. Recently, mutations in FAM20A were reported to cause amelogenesis imperfecta and gingival fibromatosis syndrome (AIGFS, which closely resembles ERS except for the renal calcifications. We characterized three families with AIGFS and identified, in each case, recessive FAM20A mutations: family 1 (c.992G>A; g.63853G>A; p.Gly331Asp, family 2 (c.720-2A>G; g.62232A>G; p.Gln241_Arg271del, and family 3 (c.406C>T; g.50213C>T; p.Arg136* and c.1432C>T; g.68284C>T; p.Arg478*. Significantly, a kidney ultrasound of the family 2 proband revealed nephrocalcinosis, revising the diagnosis from AIGFS to ERS. By characterizing teeth extracted from the family 3 proband, we demonstrated that FAM20A(-/- molars lacked true enamel, showed extensive crown and root resorption, hypercementosis, and partial replacement of resorbed mineral with bone or coalesced mineral spheres. Supported by the observation of severe ectopic calcifications in the kidneys of Fam20a null mice, we conclude that FAM20A, which has a kinase homology domain and localizes to the Golgi, is a putative Golgi kinase that plays a significant role in the regulation of biomineralization processes, and that mutations in FAM20A cause both AIGFS and ERS.

  19. Isolated inclusion body myopathy caused by a multisystem proteinopathy–linked hnRNPA1 mutation

    Science.gov (United States)

    Izumi, Rumiko; Warita, Hitoshi; Niihori, Tetsuya; Takahashi, Toshiaki; Tateyama, Maki; Suzuki, Naoki; Nishiyama, Ayumi; Shirota, Matsuyuki; Funayama, Ryo; Nakayama, Keiko; Mitsuhashi, Satomi; Nishino, Ichizo; Aoki, Yoko

    2015-01-01

    Objective: To identify the genetic cause of isolated inclusion body myopathy (IBM) with autosomal dominant inheritance in 2 families. Methods: Genetic investigations were performed using whole-exome and Sanger sequencing of the heterogeneous nuclear ribonucleoprotein A1 gene (hnRNPA1). The clinical and pathologic features of patients in the 2 families were evaluated with neurologic examinations, muscle imaging, and muscle biopsy. Results: We identified a missense p.D314N mutation in hnRNPA1, which is also known to cause familial amyotrophic lateral sclerosis, in 2 families with IBM. The affected individuals developed muscle weakness in their 40s, which slowly progressed toward a limb-girdle pattern. Further evaluation of the affected individuals revealed no apparent motor neuron dysfunction, cognitive impairment, or bone abnormality. The muscle pathology was compatible with IBM, lacking apparent neurogenic change and inflammation. Multiple immunohistochemical analyses revealed the cytoplasmic aggregation of hnRNPA1 in close association with autophagosomes and myonuclei. Furthermore, the aberrant accumulation was characterized by coaggregation with ubiquitin, sequestome-1/p62, valosin-containing protein/p97, and a variety of RNA-binding proteins (RBPs). Conclusions: The present study expands the clinical phenotype of hnRNPA1-linked multisystem proteinopathy. Mutations in hnRNPA1, and possibly hnRNPA2B1, will be responsible for isolated IBM with a pure muscular phenotype. Although the mechanisms underlying the selective skeletal muscle involvement remain to be elucidated, the immunohistochemical results suggest a broad sequestration of RBPs by the mutated hnRNPA1. PMID:27066560

  20. Mutations in KLHL40 are a frequent cause of severe autosomal-recessive nemaline myopathy.

    Science.gov (United States)

    Ravenscroft, Gianina; Miyatake, Satoko; Lehtokari, Vilma-Lotta; Todd, Emily J; Vornanen, Pauliina; Yau, Kyle S; Hayashi, Yukiko K; Miyake, Noriko; Tsurusaki, Yoshinori; Doi, Hiroshi; Saitsu, Hirotomo; Osaka, Hitoshi; Yamashita, Sumimasa; Ohya, Takashi; Sakamoto, Yuko; Koshimizu, Eriko; Imamura, Shintaro; Yamashita, Michiaki; Ogata, Kazuhiro; Shiina, Masaaki; Bryson-Richardson, Robert J; Vaz, Raquel; Ceyhan, Ozge; Brownstein, Catherine A; Swanson, Lindsay C; Monnot, Sophie; Romero, Norma B; Amthor, Helge; Kresoje, Nina; Sivadorai, Padma; Kiraly-Borri, Cathy; Haliloglu, Goknur; Talim, Beril; Orhan, Diclehan; Kale, Gulsev; Charles, Adrian K; Fabian, Victoria A; Davis, Mark R; Lammens, Martin; Sewry, Caroline A; Manzur, Adnan; Muntoni, Francesco; Clarke, Nigel F; North, Kathryn N; Bertini, Enrico; Nevo, Yoram; Willichowski, Ekkhard; Silberg, Inger E; Topaloglu, Haluk; Beggs, Alan H; Allcock, Richard J N; Nishino, Ichizo; Wallgren-Pettersson, Carina; Matsumoto, Naomichi; Laing, Nigel G

    2013-07-11

    Nemaline myopathy (NEM) is a common congenital myopathy. At the very severe end of the NEM clinical spectrum are genetically unresolved cases of autosomal-recessive fetal akinesia sequence. We studied a multinational cohort of 143 severe-NEM-affected families lacking genetic diagnosis. We performed whole-exome sequencing of six families and targeted gene sequencing of additional families. We identified 19 mutations in KLHL40 (kelch-like family member 40) in 28 apparently unrelated NEM kindreds of various ethnicities. Accounting for up to 28% of the tested individuals in the Japanese cohort, KLHL40 mutations were found to be the most common cause of this severe form of NEM. Clinical features of affected individuals were severe and distinctive and included fetal akinesia or hypokinesia and contractures, fractures, respiratory failure, and swallowing difficulties at birth. Molecular modeling suggested that the missense substitutions would destabilize the protein. Protein studies showed that KLHL40 is a striated-muscle-specific protein that is absent in KLHL40-associated NEM skeletal muscle. In zebrafish, klhl40a and klhl40b expression is largely confined to the myotome and skeletal muscle, and knockdown of these isoforms results in disruption of muscle structure and loss of movement. We identified KLHL40 mutations as a frequent cause of severe autosomal-recessive NEM and showed that it plays a key role in muscle development and function. Screening of KLHL40 should be a priority in individuals who are affected by autosomal-recessive NEM and who present with prenatal symptoms and/or contractures and in all Japanese individuals with severe NEM. Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  1. A Founder Mutation in VPS11 Causes an Autosomal Recessive Leukoencephalopathy Linked to Autophagic Defects.

    Science.gov (United States)

    Zhang, Jinglan; Lachance, Véronik; Schaffner, Adam; Li, Xianting; Fedick, Anastasia; Kaye, Lauren E; Liao, Jun; Rosenfeld, Jill; Yachelevich, Naomi; Chu, Mary-Lynn; Mitchell, Wendy G; Boles, Richard G; Moran, Ellen; Tokita, Mari; Gorman, Elizabeth; Bagley, Kaytee; Zhang, Wei; Xia, Fan; Leduc, Magalie; Yang, Yaping; Eng, Christine; Wong, Lee-Jun; Schiffmann, Raphael; Diaz, George A; Kornreich, Ruth; Thummel, Ryan; Wasserstein, Melissa; Yue, Zhenyu; Edelmann, Lisa

    2016-04-01

    Genetic leukoencephalopathies (gLEs) are a group of heterogeneous disorders with white matter abnormalities affecting the central nervous system (CNS). The causative mutation in ~50% of gLEs is unknown. Using whole exome sequencing (WES), we identified homozygosity for a missense variant, VPS11: c.2536T>G (p.C846G), as the genetic cause of a leukoencephalopathy syndrome in five individuals from three unrelated Ashkenazi Jewish (AJ) families. All five patients exhibited highly concordant disease progression characterized by infantile onset leukoencephalopathy with brain white matter abnormalities, severe motor impairment, cortical blindness, intellectual disability, and seizures. The carrier frequency of the VPS11: c.2536T>G variant is 1:250 in the AJ population (n = 2,026). VPS11 protein is a core component of HOPS (homotypic fusion and protein sorting) and CORVET (class C core vacuole/endosome tethering) protein complexes involved in membrane trafficking and fusion of the lysosomes and endosomes. The cysteine 846 resides in an evolutionarily conserved cysteine-rich RING-H2 domain in carboxyl terminal regions of VPS11 proteins. Our data shows that the C846G mutation causes aberrant ubiquitination and accelerated turnover of VPS11 protein as well as compromised VPS11-VPS18 complex assembly, suggesting a loss of function in the mutant protein. Reduced VPS11 expression leads to an impaired autophagic activity in human cells. Importantly, zebrafish harboring a vps11 mutation with truncated RING-H2 domain demonstrated a significant reduction in CNS myelination following extensive neuronal death in the hindbrain and midbrain. Thus, our study reveals a defect in VPS11 as the underlying etiology for an autosomal recessive leukoencephalopathy disorder associated with a dysfunctional autophagy-lysosome trafficking pathway.

  2. A Founder Mutation in VPS11 Causes an Autosomal Recessive Leukoencephalopathy Linked to Autophagic Defects.

    Directory of Open Access Journals (Sweden)

    Jinglan Zhang

    2016-04-01

    Full Text Available Genetic leukoencephalopathies (gLEs are a group of heterogeneous disorders with white matter abnormalities affecting the central nervous system (CNS. The causative mutation in ~50% of gLEs is unknown. Using whole exome sequencing (WES, we identified homozygosity for a missense variant, VPS11: c.2536T>G (p.C846G, as the genetic cause of a leukoencephalopathy syndrome in five individuals from three unrelated Ashkenazi Jewish (AJ families. All five patients exhibited highly concordant disease progression characterized by infantile onset leukoencephalopathy with brain white matter abnormalities, severe motor impairment, cortical blindness, intellectual disability, and seizures. The carrier frequency of the VPS11: c.2536T>G variant is 1:250 in the AJ population (n = 2,026. VPS11 protein is a core component of HOPS (homotypic fusion and protein sorting and CORVET (class C core vacuole/endosome tethering protein complexes involved in membrane trafficking and fusion of the lysosomes and endosomes. The cysteine 846 resides in an evolutionarily conserved cysteine-rich RING-H2 domain in carboxyl terminal regions of VPS11 proteins. Our data shows that the C846G mutation causes aberrant ubiquitination and accelerated turnover of VPS11 protein as well as compromised VPS11-VPS18 complex assembly, suggesting a loss of function in the mutant protein. Reduced VPS11 expression leads to an impaired autophagic activity in human cells. Importantly, zebrafish harboring a vps11 mutation with truncated RING-H2 domain demonstrated a significant reduction in CNS myelination following extensive neuronal death in the hindbrain and midbrain. Thus, our study reveals a defect in VPS11 as the underlying etiology for an autosomal recessive leukoencephalopathy disorder associated with a dysfunctional autophagy-lysosome trafficking pathway.

  3. Refsum disease is caused by mutations in the phytanoyl-CoA hydroxylase gene.

    Science.gov (United States)

    Jansen, G A; Ofman, R; Ferdinandusse, S; Ijlst, L; Muijsers, A O; Skjeldal, O H; Stokke, O; Jakobs, C; Besley, G T; Wraith, J E; Wanders, R J

    1997-10-01

    Refsum disease is an autosomal-recessively inherited disorder characterized clinically by a tetrad of abnormalities: retinitis pigmentosa, peripheral neuropathy, cerebellar ataxia and elevated protein levels in the cerebrospinal fluid (CSF) without an increase in the number of cells in the CSF. All patients exhibit accumulation of an unusual branched-chain fatty acid, phytanic acid (3,7,11,15-tetramethylhexadecanoic acid), in blood and tissues. Biochemically, the disease is caused by the deficiency of phytanoyl-CoA hydroxylase (PhyH), a peroxisomal protein catalyzing the first step in the alpha-oxidation of phytanic acid. We have purified PhyH from rat-liver peroxisomes and determined the N-terminal amino-acid sequence, as well as an additional internal amino-acid sequence obtained after Lys-C digestion of the purified protein. A search of the EST database with these partial amino-acid sequences led to the identification of the full-length human cDNA sequence encoding PhyH: the open reading frame encodes a 41.2-kD protein of 338 amino acids, which contains a cleavable peroxisomal targeting signal type 2 (PTS2). Sequence analysis of PHYH fibroblast cDNA from five patients with Refsum disease revealed distinct mutations, including a one-nucleotide deletion, a 111-nucleotide deletion and a point mutation. This analysis confirms our finding that Refsum disease is caused by a deficiency of PhyH.

  4. Familial pityriasis rubra pilaris is caused by mutations in CARD14.

    Science.gov (United States)

    Fuchs-Telem, Dana; Sarig, Ofer; van Steensel, Maurice A M; Isakov, Ofer; Israeli, Shirli; Nousbeck, Janna; Richard, Katharina; Winnepenninckx, Veronique; Vernooij, Marigje; Shomron, Noam; Uitto, Jouni; Fleckman, Philip; Richard, Gabriele; Sprecher, Eli

    2012-07-13

    Pityriasis rubra pilaris (PRP) is a papulosquamous disorder phenotypically related to psoriasis. The disease has been occasionally shown to be inherited in an autosomal-dominant fashion. To identify the genetic cause of familial PRP, we ascertained four unrelated families affected by autosomal-dominant PRP. We initially mapped PRP to 17q25.3, a region overlapping with psoriasis susceptibility locus 2 (PSORS2 [MIM 602723]). Using a combination of linkage analysis followed by targeted whole-exome sequencing and candidate-gene screening, we identified three different heterozygous mutations in CARD14, which encodes caspase recruitment domain family, member 14. CARD14 was found to be specifically expressed in the skin. CARD14 is a known activator of nuclear factor kappa B signaling, which has been implicated in inflammatory disorders. Accordingly, CARD14 levels were increased, and p65 was found to be activated in the skin of PRP-affected individuals. The present data demonstrate that autosomal-dominant PRP is allelic to familial psoriasis, which was recently shown to also be caused by mutations in CARD14. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  5. MKS1 mutations cause Joubert syndrome with agenesis of the corpus callosum.

    Science.gov (United States)

    Bader, Ingrid; Decker, E; Mayr, J A; Lunzer, V; Koch, J; Boltshauser, E; Sperl, W; Pietsch, P; Ertl-Wagner, B; Bolz, H; Bergmann, C; Rittinger, O

    2016-08-01

    Joubert syndrome (JS) is a clinically and genetically heterogeneous ciliopathy characterized by episodic hyperpnea and apnea, hypotonia, ataxia, cognitive impairment and ocular motor apraxia. The "molar tooth sign" is pathognomonic of this condition. Mutations in the MKS1 gene are a major cause of Meckel-Gruber syndrome (MKS), the most common form of syndromic neural tube defects, frequently resulting in perinatal lethality. We present the phenotype and genotype of a child with severe JS and agenesis of the corpus callosum (ACC). In our patient, a next generation sequencing (NGS) approach revealed the following two variants of the MKS1 gene: first, a novel missense variant [ c.240G > T (p.Trp80Cys)], which affects a residue that is evolutionarily highly conserved in mammals and ciliates; second, a 29 bp deletion in intron 15 [c.1408-35_1408-7del29], a founder mutation, which in a homozygous state constitutes the major cause of MKS in Finland. We review the MKS1-variants in all of the eleven JS patients reported to date and compare these patients to our case. To our knowledge, this is the first patient with Joubert syndrome and agenesis of the corpus callosum where a potentially causal genotype is provided. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. A novel heterozygous mutation in cardiac calsequestrin causes autosomal dominant catecholaminergic polymorphic ventricular tachycardia

    Science.gov (United States)

    Gray, Belinda; Bagnall, Richard D.; Lam, Lien; Ingles, Jodie; Turner, Christian; Haan, Eric; Davis, Andrew; Yang, Pei-Chi; Clancy, Colleen E.; Sy, Raymond W.; Semsarian, Christopher

    2017-01-01

    Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a lethal inherited arrhythmia syndrome characterized by adrenergically stimulated ventricular tachycardia. Mutations in the cardiac ryanodine receptor gene (RYR2) cause an autosomal dominant form of CPVT, while mutations in the cardiac calsequestrin 2 gene (CASQ2) cause an autosomal recessive form. Objective The aim of this study was to clinically and genetically evaluate a large family with severe autosomal dominant CPVT. Methods Clinical evaluation of family members was performed, including detailed history, physical examination, electrocardiogram, exercise stress test, and autopsy review of decedents. We performed genome-wide linkage analysis in 12 family members and exome sequencing in 2 affected family members. In silico models of mouse and rabbit myocyte electrophysiology were used to predict potential disease mechanisms. Results Severe CPVT with dominant inheritance in 6 members was diagnosed in a large family with 2 sudden deaths, 2 resuscitated cardiac arrests, and multiple appropriate implantable cardioverter-defibrillator shocks. A comprehensive analysis of cardiac arrhythmia genes did not reveal a pathogenic variant. Exome sequencing identified a novel heterozygous missense variant in CASQ2 (Lys180Arg) affecting a highly conserved residue, which cosegregated with disease and was absent in unaffected family members. Genome-wide linkage analysis confirmed a single linkage peak at the CASQ2 locus (logarithm of odds ratio score 3.01; θ = 0). Computer simulations predicted that haploinsufficiency was unlikely to cause the severe CPVT phenotype and suggested a dominant negative mechanism. Conclusion We show for the first time that a variant in CASQ2 causes autosomal dominant CPVT. Genetic testing in dominant CPVT should include screening for heterozygous CASQ2 variants. PMID:27157848

  7. Structural and Functional Effects of Cardiomyopathy-Causing Mutations in the Troponin T-Binding Region of Cardiac Tropomyosin.

    Science.gov (United States)

    Matyushenko, Alexander M; Shchepkin, Daniil V; Kopylova, Galina V; Popruga, Katerina E; Artemova, Natalya V; Pivovarova, Anastasia V; Bershitsky, Sergey Y; Levitsky, Dmitrii I

    2017-01-10

    Hypertrophic cardiomyopathy (HCM) is a severe heart disease caused by missense mutations in genes encoding sarcomeric proteins of cardiac muscle. Many of these mutations are identified in the gene encoding the cardiac isoform of tropomyosin (Tpm), an α-helical coiled-coil actin-binding protein that plays a key role in Ca(2+)-regulated contraction of cardiac muscle. We employed various methods to characterize structural and functional features of recombinant human Tpm species carrying HCM mutations that lie either within the troponin T-binding region in the C-terminal part of Tpm (E180G, E180V, and L185R) or near this region (I172T). The results of our structural studies show that all these mutations affect, although differently, the thermal stability of the C-terminal part of the Tpm molecule: mutations E180G and I172T destabilize this part of the molecule, whereas mutation E180V strongly stabilizes it. Moreover, various HCM-causing mutations have different and even opposite effects on the stability of the Tpm-actin complexes. Studies of reconstituted thin filaments in the in vitro motility assay have shown that those HCM-associated mutations that lie within the troponin T-binding region of Tpm similarly increase the Ca(2+) sensitivity of the sliding velocity of the filaments and impair their relaxation properties, causing a marked increase in the sliding velocity in the absence of Ca(2+), while mutation I172T decreases the Ca(2+) sensitivity and has no influence on the sliding velocity under relaxing conditions. Finally, our data demonstrate that various HCM mutations can differently affect the structural and functional properties of Tpm and cause HCM by different molecular mechanisms.

  8. Positive Selection during the Evolution of the Blood Coagulation Factors in the Context of Their Disease-Causing Mutations

    Science.gov (United States)

    Rallapalli, Pavithra M.; Orengo, Christine A.; Studer, Romain A.; Perkins, Stephen J.

    2014-01-01

    Blood coagulation occurs through a cascade of enzymes and cofactors that produces a fibrin clot, while otherwise maintaining hemostasis. The 11 human coagulation factors (FG, FII–FXIII) have been identified across all vertebrates, suggesting that they emerged with the first vertebrates around 500 Ma. Human FVIII, FIX, and FXI are associated with thousands of disease-causing mutations. Here, we evaluated the strength of selective pressures on the 14 genes coding for the 11 factors during vertebrate evolution, and compared these with human mutations in FVIII, FIX, and FXI. Positive selection was identified for fibrinogen (FG), FIII, FVIII, FIX, and FX in the mammalian Primates and Laurasiatheria and the Sauropsida (reptiles and birds). This showed that the coagulation system in vertebrates was under strong selective pressures, perhaps to adapt against blood-invading pathogens. The comparison of these results with disease-causing mutations reported in FVIII, FIX, and FXI showed that the number of disease-causing mutations, and the probability of positive selection were inversely related to each other. It was concluded that when a site was under positive selection, it was less likely to be associated with disease-causing mutations. In contrast, sites under negative selection were more likely to be associated with disease-causing mutations and be destabilizing. A residue-by-residue comparison of the FVIII, FIX, and FXI sequence alignments confirmed this. This improved understanding of evolutionary changes in FVIII, FIX, and FXI provided greater insight into disease-causing mutations, and better assessments of the codon sites that may be mutated in applications of gene therapy. PMID:25158795

  9. Missense mutations in ITPR1 cause autosomal dominant congenital nonprogressive spinocerebellar ataxia

    Directory of Open Access Journals (Sweden)

    Huang Lijia

    2012-09-01

    Full Text Available Abstract Background Congenital nonprogressive spinocerebellar ataxia is characterized by early gross motor delay, hypotonia, gait ataxia, mild dysarthria and dysmetria. The clinical presentation remains fairly stable and may be associated with cerebellar atrophy. To date, only a few families with autosomal dominant congenital nonprogressive spinocerebellar ataxia have been reported. Linkage to 3pter was demonstrated in one large Australian family and this locus was designated spinocerebellar ataxia type 29. The objective of this study is to describe an unreported Canadian family with autosomal dominant congenital nonprogressive spinocerebellar ataxia and to identify the underlying genetic causes in this family and the original Australian family. Methods and Results Exome sequencing was performed for the Australian family, resulting in the identification of a heterozygous mutation in the ITPR1 gene. For the Canadian family, genotyping with microsatellite markers and Sanger sequencing of ITPR1 gene were performed; a heterozygous missense mutation in ITPR1 was identified. Conclusions ITPR1 encodes inositol 1,4,5-trisphosphate receptor, type 1, a ligand-gated ion channel that mediates calcium release from the endoplasmic reticulum. Deletions of ITPR1 are known to cause spinocerebellar ataxia type 15, a distinct and very slowly progressive form of cerebellar ataxia with onset in adulthood. Our study demonstrates for the first time that, in addition to spinocerebellar ataxia type 15, alteration of ITPR1 function can cause a distinct congenital nonprogressive ataxia; highlighting important clinical heterogeneity associated with the ITPR1 gene and a significant role of the ITPR1-related pathway in the development and maintenance of the normal functions of the cerebellum.

  10. Papillorenal syndrome-causing missense mutations in PAX2/Pax2 result in hypomorphic alleles in mouse and human.

    Directory of Open Access Journals (Sweden)

    Ramakrishna P Alur

    2010-03-01

    Full Text Available Papillorenal syndrome (PRS, also known as renal-coloboma syndrome is an autosomal dominant disease characterized by potentially-blinding congenital optic nerve excavation and congenital kidney abnormalities. Many patients with PRS have mutations in the paired box transcription factor gene, PAX2. Although most mutations in PAX2 are predicted to result in complete loss of one allele's function, three missense mutations have been reported, raising the possibility that more subtle alterations in PAX2 function may be disease-causing. To date, the molecular behaviors of these mutations have not been explored. We describe a novel mouse model of PRS due to a missense mutation in a highly-conserved threonine residue in the paired domain of Pax2 (p.T74A that recapitulates the ocular and kidney findings of patients. This mutation is in the Pax2 paired domain at the same location as two human missense mutations. We show that all three missense mutations disrupt potentially critical hydrogen bonds in atomic models and result in reduced Pax2 transactivation, but do not affect nuclear localization, steady state mRNA levels, or the ability of Pax2 to bind its DNA consensus sequence. Moreover, these mutations show reduced steady-state levels of Pax2 protein in vitro and (for p.T74A in vivo, likely by reducing protein stability. These results suggest that hypomorphic alleles of PAX2/Pax2 can lead to significant disease in humans and mice.

  11. Disease-causing mutations in exon 11 of the medium-chain acyl-CoA dehydrogenase gene

    DEFF Research Database (Denmark)

    Andresen, B S; Jensen, T G; Bross, P

    1994-01-01

    spot. Here we describe the results from sequence analysis of exon 11 and part of the flanking introns from 36 compound heterozygous patients with MCAD deficiency. We have identified four previously unknown disease-causing mutations (M301T, S311R, R324X, and E359X) and two silent mutations in exon 11......Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most commonly recognized defect of the mitochondrial beta-oxidation in humans. It is a potentially fatal, autosomal recessive inherited defect. Most patients with MCAD deficiency are homozygous for a single disease-causing mutation (G985......), causing a change from lysine to glutamate at position 304 (K304E) in the mature MCAD. Only seven non-G985 mutations, all of which are rare, have been reported. Because the G985 mutation and three of the non-G985 mutations are located in exon 11, it has been suggested that this exon may be a mutational hot...

  12. Mutations in c10orf11, a melanocyte-differentiation gene, cause autosomal-recessive albinism.

    Science.gov (United States)

    Grønskov, Karen; Dooley, Christopher M; Østergaard, Elsebet; Kelsh, Robert N; Hansen, Lars; Levesque, Mitchell P; Vilhelmsen, Kaj; Møllgård, Kjeld; Stemple, Derek L; Rosenberg, Thomas

    2013-03-07

    Autosomal-recessive albinism is a hypopigmentation disorder with a broad phenotypic range. A substantial fraction of individuals with albinism remain genetically unresolved, and it has been hypothesized that more genes are to be identified. By using homozygosity mapping of an inbred Faroese family, we identified a 3.5 Mb homozygous region (10q22.2-q22.3) on chromosome 10. The region contains five protein-coding genes, and sequencing of one of these, C10orf11, revealed a nonsense mutation that segregated with the disease and showed a recessive inheritance pattern. Investigation of additional albinism-affected individuals from the Faroe Islands revealed that five out of eight unrelated affected persons had the nonsense mutation in C10orf11. Screening of a cohort of autosomal-recessive-albinism-affected individuals residing in Denmark showed a homozygous 1 bp duplication in C10orf11 in an individual originating from Lithuania. Immunohistochemistry showed localization of C10orf11 in melanoblasts and melanocytes in human fetal tissue, but no localization was seen in retinal pigment epithelial cells. Knockdown of the zebrafish (Danio rerio) homolog with the use of morpholinos resulted in substantially decreased pigmentation and a reduction of the apparent number of pigmented melanocytes. The morphant phenotype was rescued by wild-type C10orf11, but not by mutant C10orf11. In conclusion, we have identified a melanocyte-differentiation gene, C10orf11, which when mutated causes autosomal-recessive albinism in humans.

  13. LRPPRC mutations cause early-onset multisystem mitochondrial disease outside of the French-Canadian population.

    Science.gov (United States)

    Oláhová, Monika; Hardy, Steven A; Hall, Julie; Yarham, John W; Haack, Tobias B; Wilson, William C; Alston, Charlotte L; He, Langping; Aznauryan, Erik; Brown, Ruth M; Brown, Garry K; Morris, Andrew A M; Mundy, Helen; Broomfield, Alex; Barbosa, Ines A; Simpson, Michael A; Deshpande, Charu; Moeslinger, Dorothea; Koch, Johannes; Stettner, Georg M; Bonnen, Penelope E; Prokisch, Holger; Lightowlers, Robert N; McFarland, Robert; Chrzanowska-Lightowlers, Zofia M A; Taylor, Robert W

    2015-12-01

    Mitochondrial Complex IV [cytochrome c oxidase (COX)] deficiency is one of the most common respiratory chain defects in humans. The clinical phenotypes associated with COX deficiency include liver disease, cardiomyopathy and Leigh syndrome, a neurodegenerative disorder characterized by bilateral high signal lesions in the brainstem and basal ganglia. COX deficiency can result from mutations affecting many different mitochondrial proteins. The French-Canadian variant of COX-deficient Leigh syndrome is unique to the Saguenay-Lac-Saint-Jean region of Québec and is caused by a founder mutation in the LRPPRC gene. This encodes the leucine-rich pentatricopeptide repeat domain protein (LRPPRC), which is involved in post-transcriptional regulation of mitochondrial gene expression. Here, we present the clinical and molecular characterization of novel, recessive LRPPRC gene mutations, identified using whole exome and candidate gene sequencing. The 10 patients come from seven unrelated families of UK-Caucasian, UK-Pakistani, UK-Indian, Turkish and Iraqi origin. They resemble the French-Canadian Leigh syndrome patients in having intermittent severe lactic acidosis and early-onset neurodevelopmental problems with episodes of deterioration. In addition, many of our patients have had neonatal cardiomyopathy or congenital malformations, most commonly affecting the heart and the brain. All patients who were tested had isolated COX deficiency in skeletal muscle. Functional characterization of patients' fibroblasts and skeletal muscle homogenates showed decreased levels of mutant LRPPRC protein and impaired Complex IV enzyme activity, associated with abnormal COX assembly and reduced steady-state levels of numerous oxidative phosphorylation subunits. We also identified a Complex I assembly defect in skeletal muscle, indicating different roles for LRPPRC in post-transcriptional regulation of mitochondrial mRNAs between tissues. Patient fibroblasts showed decreased steady-state levels

  14. A case of familial paraganglioma syndrome type 4 caused by a mutation in the SDHB gene.

    Science.gov (United States)

    Drucker, Aaron M; Houlden, Robyn L

    2006-12-01

    A 40-year-old man was referred to our clinic with recurrent paragangliomas. He had undergone resection of a paraganglioma superior to the right adrenal gland at 19 years of age, resection of two para-aortic paragangliomas at 39 years of age, and resection of a paraganglioma in the interatrial septum at 40 years. The patient's mother had died at age 39 years of metastases from a carotid body tumor. MRI and CT scanning, 131I-labeled metaiodobenzylguanidine scanning, and genetic testing for a mutation in the succinate dehydrogenase complex, subunit B gene. Familial paraganglioma syndrome type 4 caused by a mutation in the succinate dehydrogenase complex, subunit B gene. The patient underwent two surgical procedures in our clinic. The first was to remove two para-aortic paragangliomas, and the second to remove a paraganglioma that involved both atria. The patient is at high risk for malignant disease and should undergo an annual monitoring program that consists of physical examination and measurement of his blood pressure and levels of urinary catecholamines and metanephrines. If these procedures suggest a recurrence of paraganglioma, 123I-labeled metaiodobenzylguanidine scanning should be performed. As he might develop nonfunctional tumors, however, he should also undergo CT scanning, MRI scanning, or both, of the neck, thorax, abdomen, and pelvis every 6-12 months. Genetic testing has been offered to family members.

  15. Mutations in LCA5 are an uncommon cause of Leber congenital amaurosis (LCA) type II.

    Science.gov (United States)

    Gerber, Sylvie; Hanein, Sylvain; Perrault, Isabelle; Delphin, Nathalie; Aboussair, Nisrine; Leowski, Corinne; Dufier, Jean-Louis; Roche, Olivier; Munnich, Arnold; Kaplan, Josseline; Rozet, Jean-Michel

    2007-12-01

    Leber congenital amaurosis (LCA) is the earliest and most severe form of inherited retinal dystrophy responsible for blindness or severe visual impairment at birth or within the first months of life. Up to date, ten LCA genes have been identified. Three of them account for ca. 43% of families and are responsible for a congenital severe stationary cone-rod dystrophy (Type I, 60% of LCA) while the seven remaining genes account for 32% of patients and are responsible for a progressive yet severe rod-cone dystrophy (Type II, 40% of LCA ). Recently, mutations in LCA5, encoding the ciliary protein lebercilin, were reported to be a rare cause of leber congenital amaurosis. The purpose of this study was to evaluate the involvement of this novel gene and to look for genotype-phenotype correlations. Here we report the identification of three novel LCA5 mutations (3/3 homozygous) in three families confirming the modest implication of this gene in our series (3/179; 1.7%). Besides, we suggest that the phenotype of these patients affected with a particularly severe form of LCA type II may represent a continuum with LCA type I.

  16. Mosaicism for dominant collagen 6 mutations as a cause for intrafamilial phenotypic variability.

    Science.gov (United States)

    Donkervoort, Sandra; Hu, Ying; Stojkovic, Tanya; Voermans, Nicol C; Foley, A Reghan; Leach, Meganne E; Dastgir, Jahannaz; Bolduc, Véronique; Cullup, Thomas; de Becdelièvre, Alix; Yang, Lin; Su, Hai; Meilleur, Katherine; Schindler, Alice B; Kamsteeg, Erik-Jan; Richard, Pascale; Butterfield, Russell J; Winder, Thomas L; Crawford, Thomas O; Weiss, Robert B; Muntoni, Francesco; Allamand, Valérie; Bönnemann, Carsten G

    2015-01-01

    Collagen 6-related dystrophies and myopathies (COL6-RD) are a group of disorders that form a wide phenotypic spectrum, ranging from severe Ullrich congenital muscular dystrophy, intermediate phenotypes, to the milder Bethlem myopathy. Both inter- and intrafamilial variable expressivity are commonly observed. We present clinical, immunohistochemical, and genetic data on four COL6-RD families with marked intergenerational phenotypic heterogeneity. This variable expression seemingly masquerades as anticipation is due to parental mosaicism for a dominant mutation, with subsequent full inheritance and penetrance of the mutation in the heterozygous offspring. We also present an additional fifth simplex patient identified as a mosaic carrier. Parental mosaicism was confirmed in the four families through quantitative analysis of the ratio of mutant versus wild-type allele (COL6A1, COL6A2, and COL6A3) in genomic DNA from various tissues, including blood, dermal fibroblasts, and saliva. Consistent with somatic mosaicism, parental samples had lower ratios of mutant versus wild-type allele compared with the fully heterozygote offspring. However, there was notable variability of the mutant allele levels between tissues tested, ranging from 16% (saliva) to 43% (fibroblasts) in one mosaic father. This is the first report demonstrating mosaicism as a cause of intrafamilial/intergenerational variability of COL6-RD, and suggests that sporadic and parental mosaicism may be more common than previously suspected.

  17. MASA syndrome is caused by mutations in the neural cell adhesion gene, L1CAM

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, C.E.; Wang, Y.; Schroer, R.J.; Stevenson, R.E. [Greenwood Genetic Center, SC (United States)

    1994-09-01

    The MASA syndrome is a recessive X-linked disorder characterized by Mental retardation, Adducted thumbs, Shuffling gait and Aphasia. Recently we found that MASA in one family was likely caused by a point mutation in exon 6 of the L1CAM gene. This gene has also been shown to be involved in X-linked hydrocephalus (HSAS). We have screened 60 patients with either sporadic HSAS or MASA as well as two additional families with MASA. For the screening, we initially utilized 3 cDNA probes for the L1CAM gene. In one of the MASA families, K8310, two affected males were found to have an altered BglII band. The band was present in their carrier mother but not in their normal brothers. This band was detected by the entire cDNA probe as well as the cDNA probe for 3{prime} end of the gene. Analysis of the L1CAM sequence indicated the altered BglII site is distal to the exon 28 but proximal to the punative poly A signal site. It is hypothesized that this point mutation alters the stability of the L1CAM mRNA. This is being tested using cell lines established from the two affected males.

  18. GABRB3 mutations: a new and emerging cause of early infantile epileptic encephalopathy.

    Science.gov (United States)

    Papandreou, Apostolos; McTague, Amy; Trump, Natalie; Ambegaonkar, Gautam; Ngoh, Adeline; Meyer, Esther; Scott, Richard H; Kurian, Manju A

    2016-04-01

    The gamma-aminobutyric acid type A receptor β3 gene (GABRB3) encodes the β3-subunit of the gamma-aminobutyric acid type A (GABAA ) receptor, which mediates inhibitory signalling within the central nervous system. Recently, GABRB3 mutations have been identified in a few patients with infantile spasms and Lennox-Gastaut syndrome. We report the clinical and electrographic features of a novel case of GABRB3-related early-onset epileptic encephalopathy. Our patient presented with neonatal hypotonia and feeding difficulties, then developed pharmacoresistant epileptic encephalopathy, characterized by multiple seizure types from 3 months of age. Electroencephalography demonstrated ictal generalized and interictal multifocal epileptiform abnormalities. Using a SureSelectXT custom multiple gene panel covering 48 early infantile epileptic encephalopathy/developmental delay genes, a novel de novo GABRB3 heterozygous missense mutation, c.860C>T (p.Thr287Ile), was identified and confirmed on Sanger sequencing. GABRB3 is an emerging cause of early-onset epilepsy. Novel genetic technologies, such as whole-exome/genome sequencing and multiple gene panels, will undoubtedly identify further cases, allowing more detailed electroclinical delineation of the GABRB3-related genotypic and phenotypic spectra.

  19. Novel mutation in SLC6A19 causing late-onset seizures in Hartnup disorder.

    Science.gov (United States)

    Cheon, Chong Kun; Lee, Beom Hee; Ko, Jung Min; Kim, Hyun-Ji; Yoo, Han-Wook

    2010-05-01

    Hartnup disorder is caused by an inborn error of neutral amino acid transport in the kidneys and intestines. It is characterized by pellagra-like rash, ataxia, and psychotic behavior. Elevated urinary neutral amino acids are the first indicator of the disorder. SLC6A19 was identified as the causative gene in autosomal-recessive Hartnup disorder, which encodes the amino acid transporter B(0)AT1, mediating neutral amino acid transport from the luminal compartment to the intracellular space. Here, we report on a Korean boy aged 8 years and 5 months with Hartnup disorder, as confirmed by SLC6A19 gene analysis. He manifested seizures, attention-deficit hyperactivity disorder, and mental retardation without pellagra or ataxia. Multiple neutral amino acids were increased in his urine, and genetic analysis of SLC6A19 revealed compound heterozygous mutations, c.908C>T (p.Ser303Leu) and c.1787_1788insG (p.Thr596fsX73), both of which are novel. A novel SLC6A19 gene mutation was associated with late-onset seizures in a Korean patient with Hartnup disorder. Copyright 2010 Elsevier Inc. All rights reserved.

  20. Paroxysmal itch caused by gain-of-function Nav1.7 mutation.

    Science.gov (United States)

    Devigili, Grazia; Eleopra, Roberto; Pierro, Tiziana; Lombardi, Raffaella; Rinaldo, Sara; Lettieri, Christian; Faber, Catharina G; Merkies, Ingemar S J; Waxman, Stephen G; Lauria, Giuseppe

    2014-09-01

    Itch is a common experience. It can occur in the course of systemic diseases and can be a manifestation of allergies or a consequence of diseases affecting the somatosensory pathway. We describe a kindred characterized by paroxysmal itch caused by a variant in SCN9A gene encoding for the Nav1.7 sodium channel. Patients underwent clinical and somatosensory profile assessment by quantitative sensory testing, nerve conduction study, autonomic cardiovascular reflex, and sympathetic skin response examination, skin biopsy with quantification of intraepidermal nerve fiber density, and SCN9A mutational analysis. The index patient, her mother, and a sister presented with a stereotypical clinical picture characterized by paroxysmal itch attacks involving the shoulders, upper back, and upper limbs, followed by transient burning pain, and triggered by environmental warmth, hot drinks, and spicy food. Somatosensory profile assessment demonstrated a remarkably identical pattern of increased cold and pain thresholds and paradoxical heat sensation. Autonomic tests were negative, whereas skin biopsy revealed decreased intraepidermal nerve fiber density in 2 of the 3 patients. All affected members harbored the 2215A>G I739V substitution in exon 13 of SCN9A gene. Pregabalin treatment reduced itch intensity and attack frequency in all patients. The co-segregation of the I739V variant in the affected members of the family provides evidence, for the first time, that paroxysmal itch can be related to a mutation in sodium channel gene.

  1. Mutations in SNRPB, encoding components of the core splicing machinery, cause cerebro-costo-mandibular syndrome.

    Science.gov (United States)

    Bacrot, Séverine; Doyard, Mathilde; Huber, Céline; Alibeu, Olivier; Feldhahn, Niklas; Lehalle, Daphné; Lacombe, Didier; Marlin, Sandrine; Nitschke, Patrick; Petit, Florence; Vazquez, Marie-Paule; Munnich, Arnold; Cormier-Daire, Valérie

    2015-02-01

    Cerebro-costo-mandibular syndrome (CCMS) is a developmental disorder characterized by the association of Pierre Robin sequence and posterior rib defects. Exome sequencing and Sanger sequencing in five unrelated CCMS patients revealed five heterozygous variants in the small nuclear ribonucleoprotein polypeptides B and B1 (SNRPB) gene. This gene includes three transcripts, namely transcripts 1 and 2, encoding components of the core spliceosomal machinery (SmB' and SmB) and transcript 3 undergoing nonsense-mediated mRNA decay. All variants were located in the premature termination codon (PTC)-introducing alternative exon of transcript 3. Quantitative RT-PCR analysis revealed a significant increase in transcript 3 levels in leukocytes of CCMS individuals compared to controls. We conclude that CCMS is due to heterozygous mutations in SNRPB, enhancing inclusion of a SNRPB PTC-introducing alternative exon, and show that this developmental disease is caused by defects in the splicing machinery. Our finding confirms the report of SNRPB mutations in CCMS patients by Lynch et al. (2014) and further extends the clinical and molecular observations.

  2. Bulldog dwarfism in Dexter cattle is caused by mutations in ACAN.

    Science.gov (United States)

    Cavanagh, Julie A L; Tammen, Imke; Windsor, Peter A; Bateman, John F; Savarirayan, Ravi; Nicholas, Frank W; Raadsma, Herman W

    2007-11-01

    Bulldog dwarfism in Dexter cattle is one of the earliest single-locus disorders described in animals. Affected fetuses display extreme disproportionate dwarfism, reflecting abnormal cartilage development (chondrodysplasia). Typically, they die around the seventh month of gestation, precipitating a natural abortion. Heterozygotes show a milder form of dwarfism, most noticeably having shorter legs. Homozygosity mapping in candidate regions in a small Dexter pedigree suggested aggrecan (ACAN) as the most likely candidate gene. Mutation screening revealed a 4-bp insertion in exon 11 (2266_2267insGGCA) (called BD1 for diagnostic testing) and a second, rarer transition in exon 1 (-198C>T) (called BD2) that cosegregate with the disorder. In chondrocytes from cattle heterozygous for the insertion, mutant mRNA is subject to nonsense-mediated decay, showing only 8% of normal expression. Genotyping in Dexter families throughout the world shows a one-to-one correspondence between genotype and phenotype at this locus. The heterozygous and homozygous-affected Dexter cattle could prove invaluable as a model for human disorders caused by mutations in ACAN.

  3. Activating glucokinase (GCK) mutations as a cause of medically responsive congenital hyperinsulinism: prevalence in children and characterisation of a novel GCK mutation

    DEFF Research Database (Denmark)

    Christesen, Henrik B T; Tribble, Nicholas D; Molven, Anders;

    2008-01-01

    OBJECTIVE: Activating glucokinase (GCK) mutations are a rarely reported cause of congenital hyperinsulinism (CHI), but the prevalence of GCK mutations is not known. METHODS: From a pooled cohort of 201 non-syndromic children with CHI from three European referral centres (Denmark, n=141; Norway, n......=26; UK, n=34), 108 children had no K(ATP)-channel (ABCC8/KCNJ11) gene abnormalities and were screened for GCK mutations. Novel GCK mutations were kinetically characterised. RESULTS: In five patients, four heterozygous GCK mutations (S64Y, T65I, W99R and A456V) were identified, out of which S64Y...... was novel. Two of the mutations arose de novo, three were dominantly inherited. All the five patients were medically responsive. In the combined Danish and Norwegian cohort, the prevalence of GCK-CHI was estimated to be 1.2% (2/167, 95% confidence interval (CI) 0-2.8%) of all the CHI patients. In the three...

  4. Mutations in SGOL1 cause a novel cohesinopathy affecting heart and gut rhythm.

    Science.gov (United States)

    Chetaille, Philippe; Preuss, Christoph; Burkhard, Silja; Côté, Jean-Marc; Houde, Christine; Castilloux, Julie; Piché, Jessica; Gosset, Natacha; Leclerc, Séverine; Wünnemann, Florian; Thibeault, Maryse; Gagnon, Carmen; Galli, Antonella; Tuck, Elizabeth; Hickson, Gilles R; El Amine, Nour; Boufaied, Ines; Lemyre, Emmanuelle; de Santa Barbara, Pascal; Faure, Sandrine; Jonzon, Anders; Cameron, Michel; Dietz, Harry C; Gallo-McFarlane, Elena; Benson, D Woodrow; Moreau, Claudia; Labuda, Damian; Zhan, Shing H; Shen, Yaoqing; Jomphe, Michèle; Jones, Steven J M; Bakkers, Jeroen; Andelfinger, Gregor

    2014-11-01

    The pacemaking activity of specialized tissues in the heart and gut results in lifelong rhythmic contractions. Here we describe a new syndrome characterized by Chronic Atrial and Intestinal Dysrhythmia, termed CAID syndrome, in 16 French Canadians and 1 Swede. We show that a single shared homozygous founder mutation in SGOL1, a component of the cohesin complex, causes CAID syndrome. Cultured dermal fibroblasts from affected individuals showed accelerated cell cycle progression, a higher rate of senescence and enhanced activation of TGF-β signaling. Karyotypes showed the typical railroad appearance of a centromeric cohesion defect. Tissues derived from affected individuals displayed pathological changes in both the enteric nervous system and smooth muscle. Morpholino-induced knockdown of sgol1 in zebrafish recapitulated the abnormalities seen in humans with CAID syndrome. Our findings identify CAID syndrome as a novel generalized dysrhythmia, suggesting a new role for SGOL1 and the cohesin complex in mediating the integrity of human cardiac and gut rhythm.

  5. Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice

    Energy Technology Data Exchange (ETDEWEB)

    Leland, Shawn; Nagarajan, Prabakaran; Polyzos, Aris; Thomas, Sharon; Samaan, George; Donnell, Robert; Marchetti, Francesco; Venkatachalam, Sundaresan

    2009-06-24

    Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice, and that the effect increases with advancing maternal age. Analysis of Bub1 heterozygous oocytes showed that aneuploidy occurred primarily during the first meiotic division and involved premature sister chromatid separation. Furthermore, aneuploidy was inherited in zygotes and resulted in the loss of embryos after implantation. The incidence of aneuploidy in zygotes was sufficient to explain the reduced litter size in matings with Bub1 heterozygous females. No effects were seen in germ cells from heterozygous males. These findings show that Bub1 dysfunction is linked to inherited aneuploidy in female germ cells and may contribute to the maternal age-related increase in aneuploidy and pregnancy loss.

  6. Crystal structure of glycogen debranching enzyme and insights into its catalysis and disease-causing mutations.

    Science.gov (United States)

    Zhai, Liting; Feng, Lingling; Xia, Lin; Yin, Huiyong; Xiang, Song

    2016-04-18

    Glycogen is a branched glucose polymer and serves as an important energy store. Its debranching is a critical step in its mobilization. In animals and fungi, the 170 kDa glycogen debranching enzyme (GDE) catalyses this reaction. GDE deficiencies in humans are associated with severe diseases collectively termed glycogen storage disease type III (GSDIII). We report crystal structures of GDE and its complex with oligosaccharides, and structure-guided mutagenesis and biochemical studies to assess the structural observations. These studies reveal that distinct domains in GDE catalyse sequential reactions in glycogen debranching, the mechanism of their catalysis and highly specific substrate recognition. The unique tertiary structure of GDE provides additional contacts to glycogen besides its active sites, and our biochemical experiments indicate that they mediate its recruitment to glycogen and regulate its activity. Combining the understanding of the GDE catalysis and functional characterizations of its disease-causing mutations provides molecular insights into GSDIII.

  7. Mutations in Three Genes Encoding Proteins Involved in Hair Shaft Formation Cause Uncombable Hair Syndrome

    DEFF Research Database (Denmark)

    Ü Basmanav, F Buket; Cau, Laura; Tafazzoli, Aylar

    2016-01-01

    Uncombable hair syndrome (UHS), also known as "spun glass hair syndrome," "pili trianguli et canaliculi," or "cheveux incoiffables" is a rare anomaly of the hair shaft that occurs in children and improves with age. UHS is characterized by dry, frizzy, spangly, and often fair hair that is resistant...... in the majority of UHS case subjects. The two enzymes PADI3 and TGM3, responsible for posttranslational protein modifications, and their target structural protein TCHH are all involved in hair shaft formation. Elucidation of the molecular outcomes of the disease-causing mutations by cell culture experiments...... and tridimensional protein models demonstrated clear differences in the structural organization and activity of mutant and wild-type proteins. Scanning electron microscopy observations revealed morphological alterations in hair coat of Padi3 knockout mice. All together, these findings elucidate the molecular genetic...

  8. POC1A truncation mutation causes a ciliopathy in humans characterized by primordial dwarfism.

    Science.gov (United States)

    Shaheen, Ranad; Faqeih, Eissa; Shamseldin, Hanan E; Noche, Ramil R; Sunker, Asma; Alshammari, Muneera J; Al-Sheddi, Tarfa; Adly, Nouran; Al-Dosari, Mohammed S; Megason, Sean G; Al-Husain, Muneera; Al-Mohanna, Futwan; Alkuraya, Fowzan S

    2012-08-10

    Primordial dwarfism (PD) is a phenotype characterized by profound growth retardation that is prenatal in onset. Significant strides have been made in the last few years toward improved understanding of the molecular underpinning of the limited growth that characterizes the embryonic and postnatal development of PD individuals. These include impaired mitotic mechanics, abnormal IGF2 expression, perturbed DNA-damage response, defective spliceosomal machinery, and abnormal replication licensing. In three families affected by a distinct form of PD, we identified a founder truncating mutation in POC1A. This gene is one of two vertebrate paralogs of POC1, which encodes one of the most abundant proteins in the Chlamydomonas centriole proteome. Cells derived from the index individual have abnormal mitotic mechanics with multipolar spindles, in addition to clearly impaired ciliogenesis. siRNA knockdown of POC1A in fibroblast cells recapitulates this ciliogenesis defect. Our findings highlight a human ciliopathy syndrome caused by deficiency of a major centriolar protein.

  9. Mutations of LRTOMT, a fusion gene with alternative reading frames, cause nonsyndromic deafness in humans.

    Science.gov (United States)

    Ahmed, Zubair M; Masmoudi, Saber; Kalay, Ersan; Belyantseva, Inna A; Mosrati, Mohamed Ali; Collin, Rob W J; Riazuddin, Saima; Hmani-Aifa, Mounira; Venselaar, Hanka; Kawar, Mayya N; Tlili, Abdelaziz; van der Zwaag, Bert; Khan, Shahid Y; Ayadi, Leila; Riazuddin, S Amer; Morell, Robert J; Griffith, Andrew J; Charfedine, Ilhem; Caylan, Refik; Oostrik, Jaap; Karaguzel, Ahmet; Ghorbel, Abdelmonem; Riazuddin, Sheikh; Friedman, Thomas B; Ayadi, Hammadi; Kremer, Hannie

    2008-11-01

    Many proteins necessary for sound transduction have been identified through positional cloning of genes that cause deafness. We report here that mutations of LRTOMT are associated with profound nonsyndromic hearing loss at the DFNB63 locus on human chromosome 11q13.3-q13.4. LRTOMT has two alternative reading frames and encodes two different proteins, LRTOMT1 and LRTOMT2, detected by protein blot analyses. LRTOMT2 is a putative methyltransferase. During evolution, new transcripts can arise through partial or complete coalescence of genes. We provide evidence that in the primate lineage LRTOMT evolved from the fusion of two neighboring ancestral genes, which exist as separate genes (Lrrc51 and Tomt) in rodents.

  10. mTOR Pathway Mutations Cause Hemimegalencephaly and Focal Cortical Dysplasia

    Science.gov (United States)

    D'Gama, Alissa M.; Geng, Ying; Couto, Javier A.; Martin, Beth; Boyle, Evan A.; LaCoursiere, Christopher M.; Hossain, Amer; Hatem, Nicole E.; Barry, Brenda; Kwiatkowski, David J.; Vinters, Harry V.; Barkovich, A. James; Shendure, Jay; Mathern, Gary W.; Walsh, Christopher A.; Poduri, Annapurna

    2015-01-01

    Focal malformations of cortical development, including focal cortical dysplasia (FCD) and hemimegalencephaly (HME), are important causes of intractable childhood epilepsy. Using targeted and exome sequencing on DNA from resected brain samples and non-brain samples from 53 patients with FCD or HME, we identified pathogenic germline and mosaic mutations in multiple PI3K/AKT pathway genes in 9 patients, and a likely pathogenic variant in 1 additional patient. Our data confirm the association of DEPDC5 with sporadic FCD but also implicate this gene for the first time in HME. Our findings suggest that modulation of the mTOR pathway may hold promise for malformation-associated epilepsy. PMID:25599672

  11. Mammalian target of rapamycin pathway mutations cause hemimegalencephaly and focal cortical dysplasia.

    Science.gov (United States)

    D'Gama, Alissa M; Geng, Ying; Couto, Javier A; Martin, Beth; Boyle, Evan A; LaCoursiere, Christopher M; Hossain, Amer; Hatem, Nicole E; Barry, Brenda J; Kwiatkowski, David J; Vinters, Harry V; Barkovich, A James; Shendure, Jay; Mathern, Gary W; Walsh, Christopher A; Poduri, Annapurna

    2015-04-01

    Focal malformations of cortical development, including focal cortical dysplasia (FCD) and hemimegalencephaly (HME), are important causes of intractable childhood epilepsy. Using targeted and exome sequencing on DNA from resected brain samples and nonbrain samples from 53 patients with FCD or HME, we identified pathogenic germline and mosaic mutations in multiple PI3K/AKT pathway genes in 9 patients, and a likely pathogenic variant in 1 additional patient. Our data confirm the association of DEPDC5 with sporadic FCD but also implicate this gene for the first time in HME. Our findings suggest that modulation of the mammalian target of rapamycin pathway may hold promise for malformation-associated epilepsy. © 2015 American Neurological Association.

  12. Intervisit variability of visual parameters in Leber congenital amaurosis caused by RPE65 mutations.

    Science.gov (United States)

    Roman, Alejandro J; Cideciyan, Artur V; Schwartz, Sharon B; Olivares, Melani B; Heon, Elise; Jacobson, Samuel G

    2013-02-15

    To determine the intervisit variability of kinetic visual fields and visual acuity in patients with Leber congenital amaurosis (LCA) caused by mutations in the RPE65 (Retinal Pigment Epithelium-specific protein 65kDa) gene. RPE65-LCA patients (n = 20; ages 11-40 years) were studied on at least two visits separated by fewer than 120 days using Goldmann visual field (GVF) and ETDRS visual acuity (VA) in a retrospective review. GVFs were quantified by computing the spherical coordinates of their vertices and calculating the solid angle subtended, and reported in normalized solid-angle units (nsu) as a percentage of average normal field extent. Repeatability coefficients were calculated using 95% confidence intervals on log(10)-converted variables. Visual field extents in RPE65-LCA spanned a wide range from 4 to 95 nsu. The repeatability coefficient was 0.248 (log(10)nsu), suggesting cutoffs for significant change (in nsu) of +77% for improvement and -44% for worsening. VA in RPE65-LCA ranged from logMAR = 0.14 to 1.96 (20/40 to 20/1250). The repeatability coefficient was 0.170 (logMAR) (±8.5 ETDRS letters). Comparisons with published studies of ungenotyped retinitis pigmentosa showed that the RPE65-LCA patients had higher variability in kinetic field extent. VA variability in RPE65-LCA fell within reported results for retinitis pigmentosa. Variability data for GVF and VA are provided to permit interpretation of the significance of increases and decreases of these functional outcomes in ongoing and planned clinical trials of therapy for LCA caused by RPE65 mutations.

  13. Mechanistic Approaches to Improve Correction of the Most Common Disease-Causing Mutation in Cystic Fibrosis.

    Directory of Open Access Journals (Sweden)

    Vedrana Bali

    Full Text Available The most common mutation in the cystic fibrosis transmembrane conductance regulator (CFTR gene leads to deletion of the phenylalanine at position 508 (ΔF508 in the CFTR protein and causes multiple folding and functional defects. Contrary to large-scale efforts by industry and academia, no significant therapeutic benefit has been achieved with a single "corrector". Therefore, investigations concentrate on drug combinations. Orkambi (Vertex Pharmaceuticals, the first FDA-approved drug for treatment of cystic fibrosis (CF caused by this mutation, is a combination of a corrector (VX-809 that facilitates ΔF508 CFTR biogenesis and a potentiator (VX-770, which improves its function. Yet, clinical trials utilizing this combination showed only modest therapeutic benefit. The low efficacy Orkambi has been attributed to VX-770-mediated destabilization of VX-809-rescued ΔF508 CFTR. Here we report that the negative effects of VX-770 can be reversed by increasing the half-life of the endoplasmic reticulum (ER form (band B of ΔF508 CFTR with another corrector (Corr-4a. Although Corr-4a alone has only minimal effects on ΔF508 CFTR rescue, it increases the half-life of ΔF508 CFTR band B when it is present during half-life measurements. Our data shows that stabilization of band B ΔF508 CFTR with Corr-4a and simultaneous rescue with VX-809, leads to a >2-fold increase in cAMP-activated, CFTRinh-172-inhibited currents compared to VX-809 alone, or VX-809+VX-770. The negative effects of VX-770 and the Corr-4a protection are specific to the native I507-ATT ΔF508 CFTR without affecting the inherently more stable, synonymous variant I507-ATC ΔF508 CFTR. Our studies emphasize that stabilization of ΔF508 CFTR band B in the ER might improve its functional rescue by Orkambi.

  14. A nonsense mutation in the acid α-glucosidase gene causes Pompe disease in Finnish and Swedish Lapphunds.

    Science.gov (United States)

    Seppälä, Eija H; Reuser, Arnold J J; Lohi, Hannes

    2013-01-01

    Pompe disease is a recessively inherited and often fatal disorder caused by the deficiency of acid α-glucosidase, an enzyme encoded by the GAA gene and needed to break down glycogen in lysosomes. This glycogen storage disease type II has been reported also in Swedish Lapphund dogs. Here we describe the genetic defect in canine Pompe disease and show that three related breeds from Scandinavia carry the same mutation. The affected dogs are homozygous for the GAA c.2237G>A mutation leading to a premature stop codon at amino acid position 746. The corresponding mutation has previously been reported in humans and causes infantile Pompe disease in combination with a second fully deleterious mutation. The affected dogs from both the Finnish as well as the Swedish breed mimic infantile-onset Pompe disease genetically, but also clinico-pathologically. Therefore this canine model provides a valuable tool for preclinical studies aimed at the development of gene therapy in Pompe disease.

  15. A novel splicing mutation in COL1A1 gene caused type I osteogenesis imperfecta in a Chinese family.

    Science.gov (United States)

    Peng, Hao; Zhang, Yuhui; Long, Zhigao; Zhao, Ding; Guo, Zhenxin; Xue, Jinjie; Xie, Zhiguo; Xiong, Zhimin; Xu, Xiaojuan; Su, Wei; Wang, Bing; Xia, Kun; Hu, Zhengmao

    2012-07-10

    Osteogenesis imperfect (OI) is a heritable connective tissue disorder with bone fragility as a cardinal manifestation, accompanied by short stature, dentinogenesis imperfecta, hyperlaxity of ligaments and skin, blue sclerae and hearing loss. Dominant form of OI is caused by mutations in the type I procollagen genes, COL1A1/A2. Here we identified a novel splicing mutation c.3207+1G>A (GenBank ID: JQ236861) in the COL1A1 gene that caused type I OI in a Chinese family. RNA splicing analysis proved that this mutation created a new splicing site at c.3200, and then led to frameshift. This result further enriched the mutation spectrum of type I procollagen genes. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Mutations in ALDH1A3 represent a frequent cause of microphthalmia/anophthalmia in consanguineous families.

    Science.gov (United States)

    Abouzeid, Hana; Favez, Tatiana; Schmid, Angélique; Agosti, Céline; Youssef, Mohammed; Marzouk, Iman; El Shakankiry, Nihal; Bayoumi, Nader; Munier, Francis L; Schorderet, Daniel F

    2014-08-01

    Anophthalmia or microphthalmia (A/M), characterized by absent or small eye, can be unilateral or bilateral and represent developmental anomalies due to the mutations in several genes. Recently, mutations in aldehyde dehydrogenase family 1, member A3 (ALDH1A3) also known as retinaldehyde dehydrogenase 3, have been reported to cause A/M. Here, we screened a cohort of 75 patients with A/M and showed that mutations in ALDH1A3 occurred in six families. Based on this series, we estimate that mutations in ALDH1A3 represent a major cause of A/M in consanguineous families, and may be responsible for approximately 10% of the cases. Screening of this gene should be performed in a first line of investigation, together with SOX2.

  17. Low penetrance and effect on protein secretion of LGI1 mutations causing autosomal dominant lateral temporal epilepsy.

    Science.gov (United States)

    Di Bonaventura, Carlo; Operto, Francesca F; Busolin, Giorgia; Egeo, Gabriella; D'Aniello, Alfredo; Vitello, Libero; Smaniotto, Gessica; Furlan, Sandra; Diani, Erica; Michelucci, Roberto; Giallonardo, Anna Teresa; Coppola, Giangennaro; Nobile, Carlo

    2011-07-01

    To describe the clinical and genetic findings of four families with autosomal dominant lateral temporal epilepsy. A personal and family history was obtained from each affected and unaffected subject along with a physical and neurologic examination. Routine electroencephalography and magnetic resonance imaging (MRI) studies were performed in almost all patients. DNAs from family members were screened for LGI1 mutations. The effects of mutations on Lgi1 protein secretion were determined in transfected culture cells. The four families included a total of 11 patients (two deceased), six of whom had lateral temporal epilepsy with auditory aura. Age at onset was in the second decade of life; seizures were well controlled by antiepileptic treatment and MRI studies were normal. We found two pathogenic LGI1 mutations with uncommonly low penetrance: the R136W mutation, previously detected in a sporadic case with telephone-induced partial seizures, gave rise to the epileptic phenotype in three of nine mutation carriers in one family; the novel C179R mutation caused epilepsy in an isolated patient from a family where the mutation segregated. Another novel pathogenic mutation, I122T, and a nonsynonymous variant, I359V, were found in the two other families. Protein secretion tests showed that the R136W and I122T mutations inhibited secretion of the mutant proteins, whereas I359V had no effect on protein secretion; C179R was not tested, because of its predictable effect on protein folding. These findings suggest that some LGI1 mutations may have a weak penetrance in families with complex inheritance pattern, or isolated patients, and that the protein secretion test, together with other predictive criteria, may help recognize pathogenic LGI1 mutations. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  18. The common p.R114W HNF4A mutation causes a distinct clinical subtype of monogenic diabetes

    Science.gov (United States)

    Laver, Thomas W; Colclough, Kevin; Shepherd, Maggie; Patel, Kashyap; Houghton, Jayne AL; Dusatkova, Petra; Pruhova, Stepanka; Morris, Andrew D; Palmer, Colin N; McCarthy, Mark I; Ellard, Sian; Hattersley, Andrew T; Weedon, Michael N

    2016-01-01

    HNF4A mutations cause increased birth weight, transient neonatal hypoglycaemia and maturity onset diabetes of the young (MODY). The most frequently reported HNF4A mutation is p.R114W (previously p.R127W) but functional studies have shown inconsistent results, there is lack of co-segregation in some pedigrees and an unexpectedly high frequency in public variant databases. We confirm that p.R114W is a pathogenic mutation with an odds ratio of 30.4 (95% CI: 9.79 – 125, P=2x10-21) for diabetes in our MODY cohort compared to controls. p.R114W heterozygotes do not have the increased birth weight of patients with other HNF4A mutations (3476g vs. 4147g, P=0.0004) and fewer patients responded to sulfonylurea treatment (48% vs. 73%, P=0.038). p.R114W has reduced penetrance; only 54% of heterozygotes developed diabetes by age 30 compared to 71% for other HNF4A mutations. We re-define p.R114W as a pathogenic mutation causing a distinct clinical subtype of HNF4A MODY with reduced penetrance, reduced sensitivity to sulfonylurea treatment and no effect on birth weight. This has implications for diabetes treatment, management of pregnancy and predictive testing of at-risk relatives. The increasing availability of large-scale sequence data is likely to reveal similar examples of rare, low-penetrance MODY mutations. PMID:27486234

  19. The Common p.R114W HNF4A Mutation Causes a Distinct Clinical Subtype of Monogenic Diabetes.

    Science.gov (United States)

    Laver, Thomas W; Colclough, Kevin; Shepherd, Maggie; Patel, Kashyap; Houghton, Jayne A L; Dusatkova, Petra; Pruhova, Stepanka; Morris, Andrew D; Palmer, Colin N; McCarthy, Mark I; Ellard, Sian; Hattersley, Andrew T; Weedon, Michael N

    2016-10-01

    HNF4A mutations cause increased birth weight, transient neonatal hypoglycemia, and maturity onset diabetes of the young (MODY). The most frequently reported HNF4A mutation is p.R114W (previously p.R127W), but functional studies have shown inconsistent results; there is a lack of cosegregation in some pedigrees and an unexpectedly high frequency in public variant databases. We confirm that p.R114W is a pathogenic mutation with an odds ratio of 30.4 (95% CI 9.79-125, P = 2 × 10(-21)) for diabetes in our MODY cohort compared with control subjects. p.R114W heterozygotes did not have the increased birth weight of patients with other HNF4A mutations (3,476 g vs. 4,147 g, P = 0.0004), and fewer patients responded to sulfonylurea treatment (48% vs. 73%, P = 0.038). p.R114W has reduced penetrance; only 54% of heterozygotes developed diabetes by age 30 years compared with 71% for other HNF4A mutations. We redefine p.R114W as a pathogenic mutation that causes a distinct clinical subtype of HNF4A MODY with reduced penetrance, reduced sensitivity to sulfonylurea treatment, and no effect on birth weight. This has implications for diabetes treatment, management of pregnancy, and predictive testing of at-risk relatives. The increasing availability of large-scale sequence data is likely to reveal similar examples of rare, low-penetrance MODY mutations.

  20. A Turkish family with Sjögren-Larsson syndrome caused by a novel ALDH3A2 mutation

    Directory of Open Access Journals (Sweden)

    Faruk Incecik

    2013-01-01

    Full Text Available Sjögren-Larsson syndrome (SLS is an inherited neurocutaneous disorder caused by mutations in the aldehyde dehydrogenase family 3 member A2 (ALDH3A2 gene that encodes fatty aldehyde dehydrogenase. Affected patients display ichthyosis, mental retardation, and spastic diplegia. More than 70 mutations in ALDH3A2 have been discovered in SLS patients. We diagnosed two brothers age of 12 and 20 years with characteristic features of this rare syndrome. Magnetic resonance imaging showed demyelinating disease in both of them. We described a novel homozygous, c. 835 T > A (p.Y279N mutation in exon 6 in two patients.

  1. Enlarged parietal foramina caused by mutations in the homeobox genes ALX4 and MSX2: from genotype to phenotype

    OpenAIRE

    2006-01-01

    Heterozygous mutations of the homeobox genes ALX4 and MSX2 cause skull defects termed enlarged parietal foramina (PFM) and cranium bifidum (CB); a single MSX2 mutation has been documented in a unique craniosynostosis (CRS) family. However, the relative mutational contribution of these genes to PFM/CB and CRS is not known and information on genotype–phenotype correlations is incomplete. We analysed ALX4 and MSX2 in 11 new unrelated cases or families with PFM/CB, 181 cases of CRS, and a single ...

  2. Methylenetetrahydrofolate reductase mutations, a genetic cause for familial recurrent neural tube defects

    Directory of Open Access Journals (Sweden)

    Laxmi V Yaliwal

    2012-01-01

    Full Text Available Methylenetetrahydrofolate reductase (MTHFR gene mutations have been implicated as risk factors for neural tube defects (NTDs. The best-characterized MTHFR genetic mutation 677C→T is associated with a 2-4 fold increased risk of NTD if patient is homozygous for this mutation. This risk factor is modulated by folate levels in the body. A second mutation in the MTHFR gene is an A→C transition at position 1298. The 1298A→C mutation is also a risk factor for NTD, but with a smaller relative risk than 677C→T mutation. Under conditions of low folate intake or high folate requirements, such as pregnancy, this mutation could become of clinical importance. We present a case report with MTHFR genetic mutation, who presented with recurrent familial pregnancy losses due to anencephaly/NTDs.

  3. Saethre-Chotzen syndrome caused by TWIST 1 gene mutations: functional differentiation from Muenke coronal synostosis syndrome.

    Science.gov (United States)

    Kress, Wolfram; Schropp, Christian; Lieb, Gabriele; Petersen, Birgit; Büsse-Ratzka, Maria; Kunz, Jürgen; Reinhart, Edeltraut; Schäfer, Wolf-Dieter; Sold, Johanna; Hoppe, Florian; Pahnke, Jan; Trusen, Andreas; Sörensen, Niels; Krauss, Jürgen; Collmann, Hartmut

    2006-01-01

    The Saethre-Chotzen syndrome (SCS) is an autosomal dominant craniosynostosis syndrome with uni- or bilateral coronal synostosis and mild limb deformities. It is caused by loss-of-function mutations of the TWIST 1 gene. In an attempt to delineate functional features separating SCS from Muenke's syndrome, we screened patients presenting with coronal suture synostosis for mutations in the TWIST 1 gene, and for the Pro250Arg mutation in FGFR3. Within a total of 124 independent pedigrees, 39 (71 patients) were identified to carry 25 different mutations of TWIST 1 including 14 novel mutations, to which six whole gene deletions were added. The 71 patients were compared with 42 subjects from 24 pedigrees carrying the Pro250Arg mutation in FGFR3 and 65 subjects from 61 pedigrees without a detectable mutation. Classical SCS associated with a TWIST 1 mutation could be separated phenotypically from the Muenke phenotype on the basis of the following features: low-set frontal hairline, gross ptosis of eyelids, subnormal ear length, dilated parietal foramina, interdigital webbing, and hallux valgus or broad great toe with bifid distal phalanx. Functional differences were even more important: intracranial hypertension as a consequence of early progressive multisutural fusion was a significant problem in SCS only, while mental delay and sensorineural hearing loss were associated with the Muenke's syndrome. Contrary to previous reports, SCS patients with complete loss of one TWIST allele showed normal mental development.

  4. Prevalent and rare mutations in the gene encoding filaggrin cause ichthyosis vulgaris and predispose individuals to atopic dermatitis.

    Science.gov (United States)

    Sandilands, Aileen; O'Regan, Gráinne M; Liao, Haihui; Zhao, Yiwei; Terron-Kwiatkowski, Ana; Watson, Rosemarie M; Cassidy, Andrew J; Goudie, David R; Smith, Frances J D; McLean, W H Irwin; Irvine, Alan D

    2006-08-01

    Mutations in the filament aggregating protein (filaggrin) gene have recently been identified as the cause of the common genetic skin disorder ichthyosis vulgaris (IV), the most prevalent inherited disorder of keratinization. The main characteristics of IV are fine-scale on the arms and legs, palmar hyperlinearity, and keratosis pilaris. Here, we have studied six Irish families with IV for mutations in filaggrin. We have identified a new mutation, 3702delG, in addition to further instances of the reported mutations R501X and 2282del4, which are common in people of European origin. A case of a 2282del4 homozygote was also identified. Mutation 3702delG terminates protein translation in filaggrin repeat domain 3, whereas both recurrent mutations occur in repeat 1. These mutations are semidominant: heterozygotes have an intermediate phenotype most readily identified by palmar hyperlinearity and in some cases fine-scale and/or keratosis pilaris, whereas homozygotes or compound heterozygotes generally have more marked ichthyosis. Interestingly, the phenotypes of individuals homozygous for R501X, 2282del4, or compound heterozygous for R501X and 3702delG, were comparable, suggesting that mutations located centrally in the filaggrin repeats are also pathogenic.

  5. Two mutational hotspots in the interleukin-2 receptor {gamma} chain gene causing human X-linked severe combined immunodeficiency

    Energy Technology Data Exchange (ETDEWEB)

    Pepper, A.E.; Puck, J.M. [National Institutes of Health, Bethesda, MD (United States); Buckley, R.H. [and others

    1995-09-01

    Human severe combined immunodeficiency (SCID), a syndrome of profoundly impaired cellular and humoral immunity, is most commonly caused by mutations in the X-linked gene for interleukin-2 (IL-2) receptor {gamma} chain (IL2RG). For mutational analysis of IL2RG in males with SCID, SSCP screening was followed by DNA sequencing. Of 40 IL2RG mutations found in unrelated SCID patients, 6 were point mutations at the CpG dinucleotide at cDNA 690-691, encoding amino acid R226. This residue lies in the extracellular domain of the protein in a region not previously recognized to be significantly conserved in the cytokine receptor gene family, 11 amino acids upstream from the highly conserved WSXWS motif. Three additional instances of mutation at another CpG dinucleotide at cDNA 879 produced a premature termination signal in the intracellular domain of IL2RG, resulting in loss of the SH2-homologous intracellular domain known to be essential for signaling from the IL-2 receptor complex. Mutations at these two hotspots constitute >20% of the X-linked SCID mutations found by our group and a similar proportion of all reported IL2RG mutations. 41 refs., 5 figs., 1 tab.

  6. Genetic heterogeneity in Rubinstein-Taybi syndrome: mutations in both the CBP and EP300 genes cause disease.

    Science.gov (United States)

    Roelfsema, Jeroen H; White, Stefan J; Ariyürek, Yavuz; Bartholdi, Deborah; Niedrist, Dunja; Papadia, Francesco; Bacino, Carlos A; den Dunnen, Johan T; van Ommen, Gert-Jan B; Breuning, Martijn H; Hennekam, Raoul C; Peters, Dorien J M

    2005-04-01

    CREB-binding protein and p300 function as transcriptional coactivators in the regulation of gene expression through various signal-transduction pathways. Both are potent histone acetyl transferases. A certain level of CREB-binding protein is essential for normal development, since inactivation of one allele causes Rubinstein-Taybi syndrome (RSTS). There is a direct link between loss of acetyl transferase activity and RSTS, which indicates that the disorder is caused by aberrant chromatin regulation. We screened the entire CREB-binding protein gene (CBP) for mutations in patients with RSTS by using methods that find point mutations and larger rearrangements. In 92 patients, we were able to identify a total of 36 mutations in CBP. By using multiple ligation-dependent probe amplification, we found not only several deletions but also the first reported intragenic duplication in a patient with RSTS. We extended the search for mutations to the EP300 gene and showed that mutations in EP300 also cause this disorder. These are the first mutations identified in EP300 for a congenital disorder.

  7. Characterization of two novel missense mutations in the AQP2 gene causing nephrogenic diabetes insipidus.

    NARCIS (Netherlands)

    Iolascon, A.; Aglio, V.; Tamma, G.; D'Apolito, M.; Addabbo, F.; Procino, G.; Simonetti, M.C.; Montini, G.; Gesualdo, L.; Debler, E.W.; Svelto, M.; Valenti, G.

    2007-01-01

    Here, we report the aquaporin 2 (AQP2) mutational analysis of a patient with nephrogenic diabetes insipidus heterozygote due to two novel missense mutations. Direct sequencing of DNA in the male patient revealed that he was compound heterozygote for two mutations in the AQP2 gene: a thymine-to-adeni

  8. Murine muscular dystrophy caused by a mutation in the laminin alpha 2 (Lama2) gene

    DEFF Research Database (Denmark)

    Xu, H; Wu, X R; Wewer, U M;

    1994-01-01

    The classic murine muscular dystrophy strain, dy, was first described almost 40 years ago. We have identified the molecular basis of an allele of dy, called dy2J, by detecting a mutation in the laminin alpha 2 chain gene--the first identified mutation in laminin-2. The G to A mutation in a splice...

  9. The TMEM43 Newfoundland mutation p.S358L causing ARVC-5 was imported from Europe and increases the stiffness of the cell nucleus

    NARCIS (Netherlands)

    Milting, Hendrik; Klauke, Baerbel; Christensen, Alex Hoerby; Muesebeck, Joerg; Walhorn, Volker; Grannemann, Soeren; Muennich, Tamara; Saric, Tomo; Rasmussen, Torsten Bloch; Jensen, Henrik Kjaerulf; Mogensen, Jens; Baecker, Carolin; Romaker, Elena; Laser, Kai Thorsten; Knyphausen, Edzard zu; Kassner, Astrid; Gummert, Jan; Judge, Daniel P.; Connors, Sean; Hodgkinson, Kathy; Young, Terry-L.; van der Zwaag, Paul A.; van Tintelen, J. Peter; Anselmetti, Dario

    2015-01-01

    Aims Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare genetic condition caused predominantly by mutations within desmosomal genes. The mutation leading to ARVC-5 was recently identified on the island of Newfoundland and caused by the fully penetrant missense mutation p.S358L in TMEM4

  10. PI3K/AKT pathway mutations cause a spectrum of brain malformations from megalencephaly to focal cortical dysplasia.

    Science.gov (United States)

    Jansen, Laura A; Mirzaa, Ghayda M; Ishak, Gisele E; O'Roak, Brian J; Hiatt, Joseph B; Roden, William H; Gunter, Sonya A; Christian, Susan L; Collins, Sarah; Adams, Carissa; Rivière, Jean-Baptiste; St-Onge, Judith; Ojemann, Jeffrey G; Shendure, Jay; Hevner, Robert F; Dobyns, William B

    2015-06-01

    Malformations of cortical development containing dysplastic neuronal and glial elements, including hemimegalencephaly and focal cortical dysplasia, are common causes of intractable paediatric epilepsy. In this study we performed multiplex targeted sequencing of 10 genes in the PI3K/AKT pathway on brain tissue from 33 children who underwent surgical resection of dysplastic cortex for the treatment of intractable epilepsy. Sequencing results were correlated with clinical, imaging, pathological and immunohistological phenotypes. We identified mosaic activating mutations in PIK3CA and AKT3 in this cohort, including cancer-associated hotspot PIK3CA mutations in dysplastic megalencephaly, hemimegalencephaly, and focal cortical dysplasia type IIa. In addition, a germline PTEN mutation was identified in a male with hemimegalencephaly but no peripheral manifestations of the PTEN hamartoma tumour syndrome. A spectrum of clinical, imaging and pathological abnormalities was found in this cohort. While patients with more severe brain imaging abnormalities and systemic manifestations were more likely to have detected mutations, routine histopathological studies did not predict mutation status. In addition, elevated levels of phosphorylated S6 ribosomal protein were identified in both neurons and astrocytes of all hemimegalencephaly and focal cortical dysplasia type II specimens, regardless of the presence or absence of detected PI3K/AKT pathway mutations. In contrast, expression patterns of the T308 and S473 phosphorylated forms of AKT and in vitro AKT kinase activities discriminated between mutation-positive dysplasia cortex, mutation-negative dysplasia cortex, and non-dysplasia epilepsy cortex. Our findings identify PI3K/AKT pathway mutations as an important cause of epileptogenic brain malformations and establish megalencephaly, hemimegalencephaly, and focal cortical dysplasia as part of a single pathogenic spectrum. © The Author (2015). Published by Oxford University Press

  11. Intronic mutations outside of Alu-repeat-rich domains of the LDL receptor gene are a cause of familial hypercholesterolemia.

    Science.gov (United States)

    Amsellem, Sabine; Briffaut, Dorothée; Carrié, Alain; Rabès, Jean Pierre; Girardet, Jean Philippe; Fredenrich, Alexandre; Moulin, Philippe; Krempf, Michel; Reznik, Yves; Vialettes, Bernard; de Gennes, Jean Luc; Brukert, Eric; Benlian, Pascale

    2002-12-01

    Familial hypercholesterolemia (FH), a frequent monogenic condition complicated by premature cardiovascular disease, is characterized by high allelic heterogeneity at the low-density lipoprotein receptor ( LDLR) locus. Despite more than a decade of genetic testing, knowledge about intronic disease-causing mutations has remained limited because of lack of available genomic sequences. Based on the finding from bioinformatic analysis that Alu repeats represent 85% of LDLR intronic sequences outside exon-intron junctions, we designed a strategy to improve the exploration of genomic regions in the vicinity of exons in 110 FH subjects from an admixed population. In the first group of 42 patients of negative mutation carriers, as previously established by former screening strategies (denaturing gradient gel electrophoresis, DNA sequencing with former primers overlapping splice-sites, Southern Blotting), about half ( n=22) were found to be carriers of at least one heterozygous mutation. Among a second group of 68 newly recruited patients, 27% of mutation carriers ( n=37) had a splicing regulatory mutation. Overall, out of the 54 mutations identified, 13 were intronic, and 18 were novel, out of which nearly half were intronic. Two novel intronic mutations (IVS8-10G-->A within the polypyrimidine tract and IVS7+10G-->A downstream of donor site) might create potential aberrant splice sites according to neural-network computed estimation, contrary to 31 common single nucleotide variations also identified at exon-intron junctions. This new strategy of detecting the most likely disease-causing LDLR mutations outside of Alu-rich genomic regions reveals that intronic mutations may have a greater impact than previously reported on the molecular basis of FH.

  12. Enlarged parietal foramina caused by mutations in the homeobox genes ALX4 and MSX2: from genotype to phenotype.

    Science.gov (United States)

    Mavrogiannis, Lampros A; Taylor, Indira B; Davies, Sally J; Ramos, Feliciano J; Olivares, José L; Wilkie, Andrew O M

    2006-02-01

    Heterozygous mutations of the homeobox genes ALX4 and MSX2 cause skull defects termed enlarged parietal foramina (PFM) and cranium bifidum (CB); a single MSX2 mutation has been documented in a unique craniosynostosis (CRS) family. However, the relative mutational contribution of these genes to PFM/CB and CRS is not known and information on genotype-phenotype correlations is incomplete. We analysed ALX4 and MSX2 in 11 new unrelated cases or families with PFM/CB, 181 cases of CRS, and a single family segregating a submicroscopic deletion of 11p11.2, including ALX4. We explored the correlations between skull defect size and age, gene, and mutation type, and reviewed additional phenotypic manifestations. Four PFM cases had mutations in either ALX4 or MSX2; including previous families, we have identified six ALX4 and six MSX2 mutations, accounting for 11/13 familial, but only 1/6 sporadic cases. The deletion family confirms the delineation of a mental retardation locus to within 1.1 Mb region of 11p11.2. Overall, no significant size difference was found between ALX4- and MSX2-related skull defects, but the ALX4 mutation p.R218Q tends to result in persistent CB and is associated with anatomical abnormalities of the posterior fossa. We conclude that PFM caused by mutations in ALX4 and MSX2 have a similar prevalence and are usually clinically indistinguishable. Mutation screening has a high pickup rate in PFM, especially in familial cases, but is not indicated in CRS.

  13. EYS Mutations Causing Autosomal Recessive Retinitis Pigmentosa: Changes of Retinal Structure and Function with Disease Progression

    Directory of Open Access Journals (Sweden)

    David B. McGuigan

    2017-07-01

    Full Text Available Mutations in the EYS (eyes shut homolog gene are a common cause of autosomal recessive (ar retinitis pigmentosa (RP. Without a mammalian model of human EYS disease, there is limited understanding of details of disease expression and rates of progression of the retinal degeneration. We studied clinically and with chromatic static perimetry, spectral-domain optical coherence tomography (OCT, and en face autofluoresence imaging, a cohort of 15 patients (ages 12–51 at first visit, some of whom had longitudinal data of function and structure. Rod sensitivity was able to be measured by chromatic perimetry in most patients at their earliest visits and some patients retained patchy rod function into the fifth decade of life. As expected from RP, cone sensitivity persisted after rod function was no longer measurable. The photoreceptor nuclear layer of the central retina was abnormal except at the fovea in most patients at first visit. Perifoveal disease measured over a period of years indicated that photoreceptor structural loss was followed by dysmorphology of the inner retina and loss of retinal pigment epithelial integrity. Although there could be variability in severity, preliminary analyses of the rates of vision loss suggested that EYS is a more rapidly progressive disease than other ciliopathies causing arRP, such as USH2A and MAK.

  14. Mutation at the Evi1 locus in Junbo mice causes susceptibility to otitis media.

    Directory of Open Access Journals (Sweden)

    Nicholas Parkinson

    2006-10-01

    Full Text Available Otitis media (OM, inflammation of the middle ear, remains the most common cause of hearing impairment in children. It is also the most common cause of surgery in children in the developed world. There is evidence from studies of the human population and mouse models that there is a significant genetic component predisposing to OM, yet nothing is known about the underlying genetic pathways involved in humans. We identified an N-ethyl-N-nitrosourea-induced dominant mouse mutant Junbo with hearing loss due to chronic suppurative OM and otorrhea. This develops from acute OM that arises spontaneously in the postnatal period, with the age of onset and early severity dependent on the microbiological status of the mice and their air quality. We have identified the causal mutation, a missense change in the C-terminal zinc finger region of the transcription factor Evi1. This protein is expressed in middle ear basal epithelial cells, fibroblasts, and neutrophil leukocytes at postnatal day 13 and 21 when inflammatory changes are underway. The identification and characterization of the Junbo mutant elaborates a novel role for Evi1 in mammalian disease and implicates a new pathway in genetic predisposition to OM.

  15. Structural Basis for a Human Glycosylation Disorder Caused by Mutation of the COG4 Gene

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, B.; Smith, R; Ungar, D; Nakamura, A; Jeffrey, P; Lupashin, V; Hughson, F

    2009-01-01

    The proper glycosylation of proteins trafficking through the Golgi apparatus depends upon the conserved oligomeric Golgi (COG) complex. Defects in COG can cause fatal congenital disorders of glycosylation (CDGs) in humans. The recent discovery of a form of CDG, caused in part by a COG4 missense mutation changing Arg 729 to Trp, prompted us to determine the 1.9 A crystal structure of a Cog4 C-terminal fragment. Arg 729 is found to occupy a key position at the center of a salt bridge network, thereby stabilizing Cog4's small C-terminal domain. Studies in HeLa cells reveal that this C-terminal domain, while not needed for the incorporation of Cog4 into COG complexes, is essential for the proper glycosylation of cell surface proteins. We also find that Cog4 bears a strong structural resemblance to exocyst and Dsl1p complex subunits. These complexes and others have been proposed to function by mediating the initial tethering between transport vesicles and their membrane targets; the emerging structural similarities provide strong evidence of a common evolutionary origin and may reflect shared mechanisms of action.

  16. Mutation at the Evi1 locus in Junbo mice causes susceptibility to otitis media.

    Science.gov (United States)

    Parkinson, Nicholas; Hardisty-Hughes, Rachel E; Tateossian, Hilda; Tsai, Hsun-Tien; Brooker, Debra; Morse, Sue; Lalane, Zuzanna; MacKenzie, Francesca; Fray, Martin; Glenister, Pete; Woodward, Anne-Marie; Polley, Sian; Barbaric, Ivana; Dear, Neil; Hough, Tertius A; Hunter, A Jackie; Cheeseman, Michael T; Brown, Steve D M

    2006-10-06

    Otitis media (OM), inflammation of the middle ear, remains the most common cause of hearing impairment in children. It is also the most common cause of surgery in children in the developed world. There is evidence from studies of the human population and mouse models that there is a significant genetic component predisposing to OM, yet nothing is known about the underlying genetic pathways involved in humans. We identified an N-ethyl-N-nitrosourea-induced dominant mouse mutant Junbo with hearing loss due to chronic suppurative OM and otorrhea. This develops from acute OM that arises spontaneously in the postnatal period, with the age of onset and early severity dependent on the microbiological status of the mice and their air quality. We have identified the causal mutation, a missense change in the C-terminal zinc finger region of the transcription factor Evi1. This protein is expressed in middle ear basal epithelial cells, fibroblasts, and neutrophil leukocytes at postnatal day 13 and 21 when inflammatory changes are underway. The identification and characterization of the Junbo mutant elaborates a novel role for Evi1 in mammalian disease and implicates a new pathway in genetic predisposition to OM.

  17. Intersex (ix) mutations of Drosophila melanogaster cause nonrandom cell death in genital disc and can induce tumours in genitals in response to decapentaplegic (dppdisk) mutations

    Indian Academy of Sciences (India)

    R. N. chatterjee; P. Chatterjee; S. Kuthe; M. Acharyya-Ari; R. Chatterjee

    2015-06-01

    In Drosophila melanogaster, the intersex (ix) is a terminally positioned gene in somatic sex determination hierarchy and function with the female specific product of double sex (DSXF) to implement female sexual differentiation. The null phenotype of ix is to transform diplo-X individuals into intersexes while leaving haplo-X animals unaffected. This study on the effect of different intersex mutations on genital disc development provides the following major results: (i) similar range of a characteristic array of morphological structures (from almost double sex terminalia to extreme reduction of terminal appendages) was displayed by the terminalia of XX ix1/ix1, XX ix2/ix2 and XX ix5/ix5 individuals; (ii) an increased number of apoptotic cells were found to occur in a localized manner in mature third instar larval genital discs of ix individuals; (iii) ix mutations can induce high frequency of neoplastic tumours in genitals in the presence of decapentaplegic (dppdisk) mutations; and (iv) heteroallelic combinations of dppdisk mutations can also induce tumours in intersex genitals with variable expressivity. On the basis of these findings, we suggest that: (i) loss of function of ix causes massive cell death in both male and female genital primordia of genital discs, resulting phenotype mimicking in male and female characteristics in genitals; and (ii) at the discs, the apoptotic cells persist as ‘undead’ cells that can induce oncogenic transformation in the neighbouring disc cells when dpp signalling is blocked or reduced by dppdisk mutations.

  18. Loss-of-function mutations in PTPN11 cause metachondromatosis, but not Ollier disease or Maffucci syndrome.

    Science.gov (United States)

    Bowen, Margot E; Boyden, Eric D; Holm, Ingrid A; Campos-Xavier, Belinda; Bonafé, Luisa; Superti-Furga, Andrea; Ikegawa, Shiro; Cormier-Daire, Valerie; Bovée, Judith V; Pansuriya, Twinkal C; de Sousa, Sérgio B; Savarirayan, Ravi; Andreucci, Elena; Vikkula, Miikka; Garavelli, Livia; Pottinger, Caroline; Ogino, Toshihiko; Sakai, Akinori; Regazzoni, Bianca M; Wuyts, Wim; Sangiorgi, Luca; Pedrini, Elena; Zhu, Mei; Kozakewich, Harry P; Kasser, James R; Seidman, Jon G; Kurek, Kyle C; Warman, Matthew L

    2011-04-01

    Metachondromatosis (MC) is a rare, autosomal dominant, incompletely penetrant combined exostosis and enchondromatosis tumor syndrome. MC is clinically distinct from other multiple exostosis or multiple enchondromatosis syndromes and is unlinked to EXT1 and EXT2, the genes responsible for autosomal dominant multiple osteochondromas (MO). To identify a gene for MC, we performed linkage analysis with high-density SNP arrays in a single family, used a targeted array to capture exons and promoter sequences from the linked interval in 16 participants from 11 MC families, and sequenced the captured DNA using high-throughput parallel sequencing technologies. DNA capture and parallel sequencing identified heterozygous putative loss-of-function mutations in PTPN11 in 4 of the 11 families. Sanger sequence analysis of PTPN11 coding regions in a total of 17 MC families identified mutations in 10 of them (5 frameshift, 2 nonsense, and 3 splice-site mutations). Copy number analysis of sequencing reads from a second targeted capture that included the entire PTPN11 gene identified an additional family with a 15 kb deletion spanning exon 7 of PTPN11. Microdissected MC lesions from two patients with PTPN11 mutations demonstrated loss-of-heterozygosity for the wild-type allele. We next sequenced PTPN11 in DNA samples from 54 patients with the multiple enchondromatosis disorders Ollier disease or Maffucci syndrome, but found no coding sequence PTPN11 mutations. We conclude that heterozygous loss-of-function mutations in PTPN11 are a frequent cause of MC, that lesions in patients with MC appear to arise following a "second hit," that MC may be locus heterogeneous since 1 familial and 5 sporadically occurring cases lacked obvious disease-causing PTPN11 mutations, and that PTPN11 mutations are not a common cause of Ollier disease or Maffucci syndrome.

  19. Loss-of-function mutations in PTPN11 cause metachondromatosis, but not Ollier disease or Maffucci syndrome.

    Directory of Open Access Journals (Sweden)

    Margot E Bowen

    2011-04-01

    Full Text Available Metachondromatosis (MC is a rare, autosomal dominant, incompletely penetrant combined exostosis and enchondromatosis tumor syndrome. MC is clinically distinct from other multiple exostosis or multiple enchondromatosis syndromes and is unlinked to EXT1 and EXT2, the genes responsible for autosomal dominant multiple osteochondromas (MO. To identify a gene for MC, we performed linkage analysis with high-density SNP arrays in a single family, used a targeted array to capture exons and promoter sequences from the linked interval in 16 participants from 11 MC families, and sequenced the captured DNA using high-throughput parallel sequencing technologies. DNA capture and parallel sequencing identified heterozygous putative loss-of-function mutations in PTPN11 in 4 of the 11 families. Sanger sequence analysis of PTPN11 coding regions in a total of 17 MC families identified mutations in 10 of them (5 frameshift, 2 nonsense, and 3 splice-site mutations. Copy number analysis of sequencing reads from a second targeted capture that included the entire PTPN11 gene identified an additional family with a 15 kb deletion spanning exon 7 of PTPN11. Microdissected MC lesions from two patients with PTPN11 mutations demonstrated loss-of-heterozygosity for the wild-type allele. We next sequenced PTPN11 in DNA samples from 54 patients with the multiple enchondromatosis disorders Ollier disease or Maffucci syndrome, but found no coding sequence PTPN11 mutations. We conclude that heterozygous loss-of-function mutations in PTPN11 are a frequent cause of MC, that lesions in patients with MC appear to arise following a "second hit," that MC may be locus heterogeneous since 1 familial and 5 sporadically occurring cases lacked obvious disease-causing PTPN11 mutations, and that PTPN11 mutations are not a common cause of Ollier disease or Maffucci syndrome.

  20. A patient with two mitochondrial DNA mutations causing PEO and LHON.

    Science.gov (United States)

    Melberg, Atle; Moslemi, Ali-Reza; Palm, Oscar; Raininko, Raili; Stålberg, Erik; Oldfors, Anders

    2009-01-01

    We report a 22-year-old man with PEO and optic atrophy. PEO developed before the onset of optic atrophy. The patient showed mitochondrial myopathy with cytochrome c oxidase deficient fibers. In skeletal muscle the patient was homoplasmic for the mtDNA G11778A Leber hereditary optic neuropathy (LHON) mutation and heteroplasmic for the mtDNA 5 kb "common" deletion mutation. In blood only the homoplasmic LHON mutation was identified. The occurrence of two pathogenic mtDNA mutations is exceedingly rare. The clinical findings in this patient indicate that the combination of the two mtDNA mutations resulted in the expected combined phenotype since the mtDNA deletion mutation accounted for the PEO and the mtDNA G11778A point mutation for the optic atrophy.

  1. Mutations in the MORC2 gene cause axonal Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Sevilla, Teresa; Lupo, Vincenzo; Martínez-Rubio, Dolores; Sancho, Paula; Sivera, Rafael; Chumillas, María J; García-Romero, Mar; Pascual-Pascual, Samuel I; Muelas, Nuria; Dopazo, Joaquín; Vílchez, Juan J; Palau, Francesc; Espinós, Carmen

    2016-01-01

    Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variants. The phenotype was variable and included patients with congenital or infantile onset, as well as others whose symptoms started in the second decade. The patients with early onset developed a spinal muscular atrophy-like picture, whereas in the later onset cases, the initial symptoms were cramps, distal weakness and sensory impairment. Weakness and atrophy progressed in a random and asymmetric fashion and involved limb girdle muscles, leading to a severe incapacity in adulthood. Sensory loss was always prominent and proportional to disease severity. Electrophysiological studies were consistent with an asymmetric axonal motor and sensory neuropathy, while fasciculations and myokymia were recorded rather frequently by needle electromyography. Sural nerve biopsy revealed pronounced multifocal depletion of myelinated fibres with some regenerative clusters and occasional small onion bulbs. Morc2 is expressed in both axons and Schwann cells of mouse peripheral nerve. Different roles in biological processes have been described for MORC2. As the silencing of Charcot-Marie-Tooth disease genes have been associated with DNA damage response, it is tempting to speculate that a deregulation of this pathway may be linked to the axonal degeneration observed in MORC2 neuropathy, thus adding a

  2. A novel splice acceptor mutation in the DSPP gene causing dentinogenesis imperfecta type II.

    Science.gov (United States)

    Kim, J W; Nam, S H; Jang, K T; Lee, S H; Kim, C C; Hahn, S H; Hu, J C C; Simmer, J P

    2004-08-01

    The dentin sialophosphoprotein (DSPP) gene (4q21.3) encodes two major noncollagenous dentin matrix proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Defects in the human gene encoding DSPP cause inherited dentin defects, and these defects can be associated with bilateral progressive high-frequency sensorineural hearing loss. Clinically, five different patterns of inherited dentin defects are distinguished and are classified as dentinogenesis imperfecta (DGI) types I, II, and III, and dentin dysplasia types I and II. The genetic basis for this clinical heterogeneity is unknown. Among the 11 members recruited from the studied kindred, five were affected with autosomal dominant DGI type II. The mutation (g.1188C-->G, IVS2-3C-->G) lay in the third from the last nucleotide of intron 2 and changed its sequence from CAG to GAG. The mutation was correlated with the affection status and was absent in 104 unaffected individuals (208 alleles) with the same ethnic and geological background. The proband was in the primary dentition stage and presented with multiple pulp exposures. The occlusal surface of his dental enamel was generally abraded, and the dentin was heavily worn and uniformly shaded brown. The dental pulp chambers appeared originally to be within normal limits without any sign of obliteration, but over time (by age 4), the pulp chambers became partially or completely obliterated. The oldest affected member (age 59) showed mild hearing loss at high-frequency (8 kHz). Permanent dentition was severely affected in the adults, who had advanced dental attrition, premature loss of teeth, and extensive dental reconstruction.

  3. Mutations in HAO1 encoding glycolate oxidase cause isolated glycolic aciduria.

    Science.gov (United States)

    Frishberg, Yaacov; Zeharia, Avraham; Lyakhovetsky, Roman; Bargal, Ruth; Belostotsky, Ruth

    2014-08-01

    The primary hyperoxalurias are a group of recessive kidney diseases, characterised by extensive accumulation of calcium oxalate that progressively coalesces into kidney stones. Oxalate overproduction is facilitated by perturbations in the metabolism of glyoxylate, the product of glycolate oxidation, and the immediate precursor of oxalate. Glycolic aciduria associated with hyperoxaluria is regarded as the hallmark of type 1 primary hyperoxaluria. The genetic basis of isolated glycolic aciduria is reported here. Two brothers, born to consanguineous healthy parents of Arab descent, were evaluated for psychomotor delay associated with triple-A-like syndrome (anisocoria, alacrima and achalasia). The proband showed markedly increased urinary glycolic acid excretion with normal excretion of oxalate, citrate and glycerate. Abdominal ultrasound showed normal-sized kidneys with normal echotexture. The genetic nature of triple-A-like syndrome in this kindred was found to be unrelated to this metabolic abnormality. Direct DNA sequencing of glycolate oxidase gene (HAO1) revealed a homozygous c.814-1G>C mutation in the invariant -1 position of intron 5 splice acceptor site. Since HAO1 is a liver-specific enzyme, the effect of this novel mutation on splicing was validated by an in vitro hybrid-minigene approach. We confirmed the appearance of an abnormal splice variant in cells transfected with mutant minigene vector. Our results pinpoint the expression of defective splice variant of glycolate oxidase as the cause of isolated asymptomatic glycolic aciduria. This observation contributes to the development of novel approaches, namely, substrate reduction, for the treatment of primary hyperoxaluria type I. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

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    Monika B Dolinska

    Full Text Available BACKGROUND: Tyrosinase (TYR catalyzes the rate-limiting, first step in melanin production and its gene (TYR is mutated in many cases of oculocutaneous albinism (OCA1, an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes. METHODOLOGY/PRINCIPAL FINDINGS: The intra-melanosomal domain of human tyrosinase (residues 19-469 and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure. CONCLUSIONS/SIGNIFICANCE: The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  5. Degeneration of proprioceptive sensory nerve endings in mice harboring amyotrophic lateral sclerosis-causing mutations.

    Science.gov (United States)

    Vaughan, Sydney K; Kemp, Zachary; Hatzipetros, Theo; Vieira, Fernando; Valdez, Gregorio

    2015-12-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that primarily targets the motor system. Although much is known about the effects of ALS on motor neurons and glial cells, little is known about its effect on proprioceptive sensory neurons. This study examines proprioceptive sensory neurons in mice harboring mutations associated with ALS, in SOD1(G93A) and TDP43(A315T) transgenic mice. In both transgenic lines, we found fewer proprioceptive sensory neurons containing fluorescently tagged cholera toxin in their soma five days after injecting this retrograde tracer into the tibialis anterior muscle. We asked whether this is due to neuronal loss or selective degeneration of peripheral nerve endings. We found no difference in the total number and size of proprioceptive sensory neuron soma between symptomatic SOD1(G93A) and control mice. However, analysis of proprioceptive nerve endings in muscles revealed early and significant alterations at Ia/II proprioceptive nerve endings in muscle spindles before the symptomatic phase of the disease. Although these changes occur alongside those at α-motor axons in SOD1(G93A) mice, Ia/II sensory nerve endings degenerate in the absence of obvious alterations in α-motor axons in TDP43(A315T) transgenic mice. We next asked whether proprioceptive nerve endings are similarly affected in the spinal cord and found that nerve endings terminating on α-motor neurons are affected during the symptomatic phase and after peripheral nerve endings begin to degenerate. Overall, we show that Ia/II proprioceptive sensory neurons are affected by ALS-causing mutations, with pathological changes starting at their peripheral nerve endings.

  6. Connexin26 Mutations Causing Palmoplantar Keratoderma and Deafness Interact with Connexin43, Modifying Gap Junction and Hemichannel Properties.

    Science.gov (United States)

    Shuja, Zunaira; Li, Leping; Gupta, Shashank; Meşe, Gülistan; White, Thomas W

    2016-01-01

    Mutations in GJB2 (connexin [Cx]26) cause either deafness or deafness associated with skin diseases. That different disorders can be caused by distinct mutations within the same gene suggests that unique channel activities are influenced by each class of mutation. We have examined the functional characteristics of two human mutations, Cx26-H73R and Cx26-S183F, causing palmoplantar keratoderma (PPK) and deafness. Both failed to form gap junction channels or hemichannels when expressed alone. Coexpression of the mutants with wild-type Cx43 showed a transdominant inhibition of Cx43 gap junction channels, without reductions in Cx43 protein synthesis. In addition, the presence of mutant Cx26 shifted Cx43 channel gating and kinetics toward a more Cx26-like behavior. Coimmunoprecipitation showed Cx43 being pulled down more efficiently with mutant Cx26 than wild-type, confirming the enhanced formation of heteromeric connexons. Finally, the formation of heteromeric connexons resulted in significantly increased Cx43 hemichannel activity in the presence of Cx26 mutants. These findings suggest a common mechanism whereby Cx26 mutations causing PPK and deafness transdominantly influence multiple functions of wild-type Cx43. They also implicate a role for aberrant hemichannel activity in the pathogenesis of PPK and further highlight an emerging role for Cx43 in genetic skin diseases.

  7. Novel PAX9 and COL1A2 missense mutations causing tooth agenesis and OI/DGI without skeletal abnormalities.

    Directory of Open Access Journals (Sweden)

    Shih-Kai Wang

    Full Text Available Inherited dentin defects are classified into three types of dentinogenesis imperfecta (DGI and two types of dentin dysplasia (DD. The genetic etiology of DD-I is unknown. Defects in dentin sialophosphoprotein (DSPP cause DD type II and DGI types II and III. DGI type I is the oral manifestation of osteogenesis imperfecta (OI, a systemic disease typically caused by defects in COL1A1 or COL1A2. Mutations in MSX1, PAX9, AXIN2, EDA and WNT10A can cause non-syndromic familial tooth agenesis. In this study a simplex pattern of clinical dentinogenesis imperfecta juxtaposed with a dominant pattern of hypodontia (mild tooth agenesis was evaluated, and available family members were recruited. Mutational analyses of the candidate genes for DGI and hypodontia were performed and the results validated. A spontaneous novel mutation in COL1A2 (c.1171G>A; p.Gly391Ser causing only dentin defects and a novel mutation in PAX9 (c.43T>A; p.Phe15Ile causing hypodontia were identified and correlated with the phenotypic presentations in the family. Bone radiographs of the proband's dominant leg and foot were within normal limits. We conclude that when no DSPP mutation is identified in clinically determined isolated DGI cases, COL1A1 and COL1A2 should be considered as candidate genes. PAX9 mutation p.Phe15Ile within the N-terminal β-hairpin structure of the PAX9 paired domain causes tooth agenesis.

  8. De Novo and Inherited Mutations in COL4A2, Encoding the Type IV Collagen α2 Chain Cause Porencephaly

    Science.gov (United States)

    Yoneda, Yuriko; Haginoya, Kazuhiro; Arai, Hiroshi; Yamaoka, Shigeo; Tsurusaki, Yoshinori; Doi, Hiroshi; Miyake, Noriko; Yokochi, Kenji; Osaka, Hitoshi; Kato, Mitsuhiro; Matsumoto, Naomichi; Saitsu, Hirotomo

    2012-01-01

    Porencephaly is a neurological disorder characterized by fluid-filled cysts or cavities in the brain that often cause hemiplegia. It has been suggested that porencephalic cavities result from focal cerebral degeneration involving hemorrhages. De novo or inherited heterozygous mutations in COL4A1, which encodes the type IV α1 collagen chain that is essential for structural integrity for vascular basement membranes, have been reported in individuals with porencephaly. Most mutations occurred at conserved Gly residues in the Gly-Xaa-Yaa repeats of the triple-helical domain, leading to alterations of the α1α1α2 heterotrimers. Here we report on two individuals with porencephaly caused by a heterozygous missense mutation in COL4A2, which encodes the type IV α2 collagen chain. Mutations c.3455G>A and c.3110G>A, one in each of the individuals, cause Gly residues in the Gly-Xaa-Yaa repeat to be substituted as p.Gly1152Asp and p.Gly1037Glu, respectively, probably resulting in alterations of the α1α1α2 heterotrimers. The c.3455G>A mutation was found in the proband's mother, who showed very mild monoparesis of the left upper extremity, and the maternal elder uncle, who had congenital hemiplegia. The maternal grandfather harboring the mutation is asymptomatic. The c.3110G>A mutation occurred de novo. Our study confirmed that abnormalities of the α1α1α2 heterotrimers of type IV collagen cause porencephaly and stresses the importance of screening for COL4A2 as well as for COL4A1. PMID:22209246

  9. No Association between Loss-of-Function Mutations in filaggrin and Diabetes, Cardiovascular Disease, and All-Cause Mortality

    Science.gov (United States)

    Husemoen, Lise Lotte N.; Skaaby, Tea; Jørgensen, Torben; Thyssen, Jacob P.; Meldgaard, Michael; Szecsi, Pal B.; Stender, Steen; Johansen, Jeanne Duus; Linneberg, Allan

    2013-01-01

    Background Common loss-of-function mutations in the filaggrin gene (FLG) are a major predisposing risk factor for atopic disease due to reduced epidermal filaggrin protein levels. We previously observed an association between these mutations and type 2 diabetes and hypothesized that an inherited impairment of skin barrier functions could facilitate low-grade inflammation and hence increase the risk of diabetes and cardiovascular disease. We examined the association between loss-of-function mutations in FLG and diabetes, stroke, ischemic heart disease (IHD), and all-cause mortality in the general population. Methods The R501X and 2282del4 loss-of function mutations in FLG were genotyped in four Danish study populations including a total of 13373 adults aged 15-77 years. Two of the studies also genotyped the R2447X mutation. By linkage to Danish national central registers we obtained information for all participants on dates of diagnoses of diabetes, stroke, and IHD, as well as all-cause mortality. Data were analyzed by Cox proportional hazard models and combined by fixed effect meta-analyses. Results In meta-analyses combining the results from the four individual studies, carriage of loss-of-function mutations in FLG was not associated with incident diabetes (hazard ratio (HR) (95% confidence intervals (CI)) = 0.95 (0.73, 1.23), stroke (HR (95% CI) = 1.27 (0.97, 1.65), ischemic heart disease (HR (95%CI) = 0.92 (0.71, 1.19), and all-cause mortality (HR (95%CI) = 1.02 (0.83, 1.25)). Similar results were obtained when including prevalent cases in logistic regression models. Conclusion Our results suggest that loss-of-function mutations in FLG are not associated with type 2 diabetes, cardiovascular disease, and all-cause mortality. However, larger studies with longer follow-up are needed to exclude any associations. PMID:24367652

  10. No association between loss-of-function mutations in filaggrin and diabetes, cardiovascular disease, and all-cause mortality.

    Directory of Open Access Journals (Sweden)

    Lise Lotte N Husemoen

    Full Text Available BACKGROUND: Common loss-of-function mutations in the filaggrin gene (FLG are a major predisposing risk factor for atopic disease due to reduced epidermal filaggrin protein levels. We previously observed an association between these mutations and type 2 diabetes and hypothesized that an inherited impairment of skin barrier functions could facilitate low-grade inflammation and hence increase the risk of diabetes and cardiovascular disease. We examined the association between loss-of-function mutations in FLG and diabetes, stroke, ischemic heart disease (IHD, and all-cause mortality in the general population. METHODS: The R501X and 2282del4 loss-of function mutations in FLG were genotyped in four Danish study populations including a total of 13373 adults aged 15-77 years. Two of the studies also genotyped the R2447X mutation. By linkage to Danish national central registers we obtained information for all participants on dates of diagnoses of diabetes, stroke, and IHD, as well as all-cause mortality. Data were analyzed by Cox proportional hazard models and combined by fixed effect meta-analyses. RESULTS: In meta-analyses combining the results from the four individual studies, carriage of loss-of-function mutations in FLG was not associated with incident diabetes (hazard ratio (HR (95% confidence intervals (CI = 0.95 (0.73, 1.23, stroke (HR (95% CI = 1.27 (0.97, 1.65, ischemic heart disease (HR (95%CI = 0.92 (0.71, 1.19, and all-cause mortality (HR (95%CI = 1.02 (0.83, 1.25. Similar results were obtained when including prevalent cases in logistic regression models. CONCLUSION: Our results suggest that loss-of-function mutations in FLG are not associated with type 2 diabetes, cardiovascular disease, and all-cause mortality. However, larger studies with longer follow-up are needed to exclude any associations.

  11. A novel CYP27B1 mutation causes a feline vitamin D-dependent rickets type IA.

    Science.gov (United States)

    Grahn, Robert A; Ellis, Melanie R; Grahn, Jennifer C; Lyons, Leslie A

    2012-08-01

    A 12-week-old domestic cat presented at a local veterinary clinic with hypocalcemia and skeletal abnormalities suggestive of rickets. Osteomalacia (rickets) is a disease caused by impaired bone mineralization leading to an increased prevalence of fractures and deformity. Described in a variety of species, rickets is most commonly caused by vitamin D or calcium deficiencies owing to both environmental and or genetic abnormalities. Vitamin D-dependent rickets type 1A (VDDR-1A) is a result of the enzymatic pathway defect caused by mutations in the 25-hydroxyvitamin D(3)-1-alpha-hydroxylase gene [cytochrome P27 B1 (CYP27B1)]. Calcitriol, the active form of vitamin D(3), regulates calcium homeostasis, which requires sufficient dietary calcium availability and correct hormonal function for proper bone growth and maintenance. Patient calcitriol concentrations were low while calcidiol levels were normal suggestive of VDDR-1A. The entire DNA coding sequencing of CYP27B1 was evaluated. The affected cat was wild type for previously identified VDDR-1A causative mutations. However, six novel mutations were identified, one of which was a nonsense mutation at G637T in exon 4. The exon 4 G637T nonsense mutation results in a premature protein truncation, changing a glutamic acid to a stop codon, E213X, likely causing the clinical presentation of rickets. The previously documented genetic mutation resulting in feline VDDR-1A rickets, as well as the case presented in this research, result from novel exon 4 CYP27B1 mutations, thus exon 4 should be the initial focus of future sequencing efforts.

  12. A Hereditary Enteropathy Caused by Mutations in the SLCO2A1 Gene, Encoding a Prostaglandin Transporter.

    Directory of Open Access Journals (Sweden)

    Junji Umeno

    2015-11-01

    Full Text Available Previously, we proposed a rare autosomal recessive inherited enteropathy characterized by persistent blood and protein loss from the small intestine as chronic nonspecific multiple ulcers of the small intestine (CNSU. By whole-exome sequencing in five Japanese patients with CNSU and one unaffected individual, we found four candidate mutations in the SLCO2A1 gene, encoding a prostaglandin transporter. The pathogenicity of the mutations was supported by segregation analysis and genotyping data in controls. By Sanger sequencing of the coding regions, 11 of 12 other CNSU patients and 2 of 603 patients with a diagnosis of Crohn's disease were found to have homozygous or compound heterozygous SLCO2A1 mutations. In total, we identified recessive SLCO2A1 mutations located at seven sites. Using RT-PCR, we demonstrated that the identified splice-site mutations altered the RNA splicing, and introduced a premature stop codon. Tracer prostaglandin E2 uptake analysis showed that the mutant SLCO2A1 protein for each mutation exhibited impaired prostaglandin transport. Immunohistochemistry and immunofluorescence analyses revealed that SLCO2A1 protein was expressed on the cellular membrane of vascular endothelial cells in the small intestinal mucosa in control subjects, but was not detected in affected individuals. These findings indicate that loss-of-function mutations in the SLCO2A1 gene encoding a prostaglandin transporter cause the hereditary enteropathy CNSU. We suggest a more appropriate nomenclature of "chronic enteropathy associated with SLCO2A1 gene" (CEAS.

  13. De novo heterozygous mutations in SMC3 cause a range of Cornelia de Lange syndrome-overlapping phenotypes.

    Science.gov (United States)

    Gil-Rodríguez, María Concepción; Deardorff, Matthew A; Ansari, Morad; Tan, Christopher A; Parenti, Ilaria; Baquero-Montoya, Carolina; Ousager, Lilian B; Puisac, Beatriz; Hernández-Marcos, María; Teresa-Rodrigo, María Esperanza; Marcos-Alcalde, Iñigo; Wesselink, Jan-Jaap; Lusa-Bernal, Silvia; Bijlsma, Emilia K; Braunholz, Diana; Bueno-Martinez, Inés; Clark, Dinah; Cooper, Nicola S; Curry, Cynthia J; Fisher, Richard; Fryer, Alan; Ganesh, Jaya; Gervasini, Cristina; Gillessen-Kaesbach, Gabriele; Guo, Yiran; Hakonarson, Hakon; Hopkin, Robert J; Kaur, Maninder; Keating, Brendan J; Kibaek, María; Kinning, Esther; Kleefstra, Tjitske; Kline, Antonie D; Kuchinskaya, Ekaterina; Larizza, Lidia; Li, Yun R; Liu, Xuanzhu; Mariani, Milena; Picker, Jonathan D; Pié, Ángeles; Pozojevic, Jelena; Queralt, Ethel; Richer, Julie; Roeder, Elizabeth; Sinha, Anubha; Scott, Richard H; So, Joyce; Wusik, Katherine A; Wilson, Louise; Zhang, Jianguo; Gómez-Puertas, Paulino; Casale, César H; Ström, Lena; Selicorni, Angelo; Ramos, Feliciano J; Jackson, Laird G; Krantz, Ian D; Das, Soma; Hennekam, Raoul C M; Kaiser, Frank J; FitzPatrick, David R; Pié, Juan

    2015-04-01

    Cornelia de Lange syndrome (CdLS) is characterized by facial dysmorphism, growth failure, intellectual disability, limb malformations, and multiple organ involvement. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), account for at least 70% of patients with CdLS or CdLS-like phenotypes. To date, only the clinical features from a single CdLS patient with SMC3 mutation has been published. Here, we report the efforts of an international research and clinical collaboration to provide clinical comparison of 16 patients with CdLS-like features caused by mutations in SMC3. Modeling of the mutation effects on protein structure suggests a dominant-negative effect on the multimeric cohesin complex. When compared with typical CdLS, many SMC3-associated phenotypes are also characterized by postnatal microcephaly but with a less distinctive craniofacial appearance, a milder prenatal growth retardation that worsens in childhood, few congenital heart defects, and an absence of limb deficiencies. While most mutations are unique, two unrelated affected individuals shared the same mutation but presented with different phenotypes. This work confirms that de novo SMC3 mutations account for ∼ 1%-2% of CdLS-like phenotypes. © 2015 WILEY PERIODICALS, INC.

  14. Uroporphyrinogen III synthase erythroid promoter mutations in adjacent GATA1 and CP2 elements cause congenital erythropoietic porphyria.

    Science.gov (United States)

    Solis, C; Aizencang, G I; Astrin, K H; Bishop, D F; Desnick, R J

    2001-03-01

    Congenital erythropoietic porphyria, an autosomal recessive inborn error of heme biosynthesis, results from the markedly deficient activity of uroporphyrinogen III synthase. Extensive mutation analyses of 40 unrelated patients only identified approximately 90% of mutant alleles. Sequencing the recently discovered erythroid-specific promoter in six patients with a single undefined allele identified four novel mutations clustered in a 20-bp region: (a) a -70T to C transition in a putative GATA-1 consensus binding element, (b) a -76G to A transition, (c) a -86C to A transversion in three unrelated patients, and (d) a -90C to A transversion in a putative CP2 binding motif. Also, a -224T to C polymorphism was present in approximately 4% of 200 unrelated Caucasian alleles. We inserted these mutant sequences into luciferase reporter constructs. When transfected into K562 erythroid cells, these constructs yielded 3 +/- 1, 54 +/- 3, 43 +/- 6, and 8 +/- 1%, respectively, of the reporter activity conferred by the wild-type promoter. Electrophoretic mobility shift assays indicated that the -70C mutation altered GATA1 binding, whereas the adjacent -76A mutation did not. Similarly, the -90C mutation altered CP2 binding, whereas the -86A mutation did not. Thus, these four pathogenic erythroid promoter mutations impaired erythroid-specific transcription, caused CEP, and identified functionally important GATA1 and CP2 transcriptional binding elements for erythroid-specific heme biosynthesis.

  15. Rapid detection of the ACMG/ACOG-recommended 23 CFTR disease-causing mutations using ion torrent semiconductor sequencing.

    Science.gov (United States)

    Elliott, Aaron M; Radecki, Joy; Moghis, Bellal; Li, Xiang; Kammesheidt, Anja

    2012-04-01

    Cystic fibrosis (CF) is one of the most frequently diagnosed autosomal-recessive diseases in the Caucasian population. For general-population CF carrier screening, the American College of Medical Genetics (ACMG)/American College of Obstetricians and Gynecologists (ACOG) have recommended a core panel of 23 mutations that will identify 49-98% of carriers, depending on ethnic background. Using a genotyping technology that can rapidly identify disease-causing mutations is important for high-throughput general-population carrier screening, confirming clinical diagnosis, determining treatment options, and prenatal diagnosis. Here, we describe a proof-of-concept study to determine whether the Ion Torrent Personal Genome Machine (PGM) sequencer platform can reliably identify all ACMG/ACOG 23 CF transmembrane conductance regulator (CFTR) mutations. A WT CF specimen along with mutant DNA specimens representing all 23 CFTR mutations were sequenced bidirectionally on the Ion Torrent 314 chip to determine the accuracy of the PGM for CFTR variant detection. We were able to reliably identify all of the targeted mutations except for 2184delA, which lies in a difficult, 7-mer homopolymer tract. Based on our study, we believe PGM sequencing may be a suitable technology for identifying CFTR mutations in the future. However, as a result of the elevated rate of base-calling errors within homopolymer stretches, mutations within such regions currently need to be evaluated carefully using an alternative method.

  16. Mapping and exome sequencing identifies a mutation in the IARS gene as the cause of hereditary perinatal weak calf syndrome.

    Directory of Open Access Journals (Sweden)

    Takashi Hirano

    Full Text Available We identified an IARS (isoleucyl-tRNA synthetase c.235G>C (p.Val79Leu substitution as the causative mutation for neonatal weakness with intrauterine growth retardation (perinatal weak calf syndrome. In Japanese Black cattle, the syndrome was frequently found in calves sired by Bull A. Hence, we employed homozygosity mapping and linkage analysis. In order to identify the perinatal weak calf syndrome locus in a 4.04-Mb region of BTA 8, we analysed a paternal half-sibling family with a BovineSNP50 BeadChip and microsatellites. In this critical region, we performed exome sequencing to identify a causative mutation. Three variants were detected as possible candidates for causative mutations that were predicted to disrupt the protein function, including a G>C (p.Val79Leu mutation in IARS c.235. The IARS c.235G>C mutation was not a homozygous risk allele in the 36 healthy offspring of Bull A. Moreover, the IARS Val79 residue and its flanking regions were evolutionarily and highly conserved. The IARS mutant (Leu79 had decreased aminoacylation activity. Additionally, the homozygous mutation was not found in any of 1526 healthy cattle. Therefore, we concluded that the IARS c.235G>C mutation was the cause of hereditary perinatal weak calf syndrome.

  17. Dense cataract and microphthalmia (dcm) in BALB/c mice is caused by mutations in the GJA8 locus

    Indian Academy of Sciences (India)

    Baskar Bakthavachalu; Sarmishtha Kalanke; Sanjeev Galande; B. Ramanamurthy; Pradeep Parab; Kalidas N. Kohale; Vasudevan Seshadri

    2010-08-01

    A spontaneous mutation in BALB/c mice that causes congenital dense cataract and microphthalmia (dcm) was reported previously. This abnormality was found to be inheritable and the mode of inheritance indicated that this phenotype is due to mutation of an autosomal recessive gene. We performed genetic screen to identify the underlying mutations through linkage analysis with the dcm progenies of F1 intercross. We identified the region of mutation on chromosome 3 and further mapping and sequence analysis identified the mutation in the GJA8 gene that encodes for connexin 50. The mutation represents a single nucleotide change at position 64 (G to C) that results in a change in the amino acid glycine to arginine at position 22 (G22R) and is identical to the mutation previously characterized as lop10. However, the phenotype of these mice differ from that of lop10 mice and since it is one of the very few genetic models with recessive pattern of inheritance, we propose that dcm mice can serve as a useful model for studying the dynamics and interaction of the gap junction formation in mouse eye development.

  18. Compound heterozygous PNPLA6 mutations cause Boucher-Neuhäuser syndrome with late-onset ataxia.

    Science.gov (United States)

    Deik, A; Johannes, B; Rucker, J C; Sánchez, E; Brodie, S E; Deegan, E; Landy, K; Kajiwara, Y; Scelsa, S; Saunders-Pullman, R; Paisán-Ruiz, C

    2014-12-01

    PNPLA6 mutations, known to be associated with the development of motor neuron phenotypes, have recently been identified in families with Boucher-Neuhäuser syndrome. Boucher-Neuhäuser is a rare autosomal recessive syndrome characterized by the co-occurrence of cerebellar ataxia, hypogonadotropic hypogonadism, and chorioretinal dystrophy. Gait ataxia in Boucher-Neuhäuser usually manifests before early adulthood, although onset in the third or fourth decade has also been reported. However, given the recent identification of PNPLA6 mutations as the cause of this condition, the determining factors of age of symptom onset still need to be established. Here, we have identified a sporadic Boucher-Neuhäuser case with late-onset gait ataxia and relatively milder retinal changes due to compound heterozygous PNPLA6 mutations. Compound heterozygosity was confirmed by cloning and sequencing the patient's genomic DNA from coding exons 26-29. Furthermore, both mutations (one novel and one known) fell in the phospholipase esterase domain, where most pathogenic mutations seem to cluster. Taken together, we herein confirm PNPLA6 mutations as the leading cause of Boucher-Neuhäuser syndrome and suggest inquiring about a history of hypogonadism or visual changes in patients presenting with late-onset gait ataxia. We also advocate for neuroophthalmologic evaluation in suspected cases.

  19. Genotype–phenotype characteristics and baseline natural history of heritable neuropathies caused by mutations in the MPZ gene

    Science.gov (United States)

    Feely, Shawna; Scherer, Steven S.; Herrmann, David N.; Burns, Joshua; Muntoni, Francesco; Li, Jun; Siskind, Carly E.; Day, John W.; Laura, Matilde; Sumner, Charlotte J.; Lloyd, Thomas E.; Ramchandren, Sindhu; Shy, Rosemary R.; Grider, Tiffany; Bacon, Chelsea; Finkel, Richard S.; Yum, Sabrina W.; Moroni, Isabella; Piscosquito, Giuseppe; Pareyson, Davide; Reilly, Mary M.; Shy, Michael E.

    2015-01-01

    We aimed to characterize genotype–phenotype correlations and establish baseline clinical data for peripheral neuropathies caused by mutations in the myelin protein zero (MPZ) gene. MPZ mutations are the second leading cause of Charcot–Marie–Tooth disease type 1. Recent research makes clinical trials for patients with MPZ mutations a realistic possibility. However, the clinical severity varies with different mutations and natural history data on progression is sparse. We present cross-sectional data to begin to define the phenotypic spectrum and clinical baseline of patients with these mutations. A cohort of patients with MPZ gene mutations was identified in 13 centres of the Inherited Neuropathies Consortium - Rare Disease Clinical Research Consortium (INC-RDCRC) between 2009 and 2012 and at Wayne State University between 1996 and 2009. Patient phenotypes were quantified by the Charcot–Marie–Tooth disease neuropathy score version 1 or 2 and the Charcot–Marie–Tooth disease paediatric scale outcome instruments. Genetic testing was performed in all patients and/or in first- or second-degree relatives to document mutation in MPZ gene indicating diagnosis of Charcot–Marie–Tooth disease type 1B. There were 103 patients from 71 families with 47 different MPZ mutations with a mean age of 40 years (range 3–84 years). Patients and mutations were separated into infantile, childhood and adult-onset groups. The infantile onset group had higher Charcot–Marie–Tooth disease neuropathy score version 1 or 2 and slower nerve conductions than the other groups, and severity increased with age. Twenty-three patients had no family history of Charcot–Marie–Tooth disease. Sixty-one patients wore foot/ankle orthoses, 19 required walking assistance or support, and 10 required wheelchairs. There was hearing loss in 21 and scoliosis in 17. Forty-two patients did not begin walking until after 15 months of age. Half of the infantile onset patients then required

  20. Novel WISP3 mutations causing spondyloepiphyseal dysplasia tarda with progressive arthropathy in two unrelated Chinese families.

    Science.gov (United States)

    Liu, Limin; Li, Nan; Zhao, Zhen; Li, Wei; Xia, Weibo

    2015-03-01

    Spondyloepiphyseal dysplasia tarda with progressive arthropathy (SEDT-PA) is an autosomal recessive skeletal disorder resulting from pathogenic mutations in the Wnt1-inducible signaling pathway protein 3 (WISP3) gene. This disorder predominantly involves the skeletal system, with the leading features of platyspondyly, metaphyseal dysplasia of limbs and extremities, and progressive degeneration of joints. To date, 53 distinct forms of WISP3 mutations have been detected globally, eleven of which originated from Chinese patients. In the current study, we reported the clinical manifestations and radiographic features of two unrelated Chinese SEDT-PA patients. Through genetic analysis, two novel mutations (c.624delA, c.105dupT) as well as one recurrent mutation (c.342T>G) were identified in the WISP3 gene. Our study contributed to the further expansion of the WISP3 mutation spectrum, and demonstrated the genotype-phenotype relationship between mutations in the WISP3 gene and clinical findings of SEDT-PA.

  1. Identification of CNGA3 mutations in 46 families: common cause of achromatopsia and cone-rod dystrophies in Chinese patients.

    Science.gov (United States)

    Li, Shiqiang; Huang, Li; Xiao, Xueshan; Jia, Xiaoyun; Guo, Xiangming; Zhang, Qingjiong

    2014-09-01

    Mutations in CNGA3 are the most common cause of achromatopsia and cone-rod dystrophies. To identify CNGA3 mutations in patients with cone dystrophies or Leber congenital amaurosis. Clinical data and genomic DNA in 267 Chinese probands from 138 families with cone dystrophies and 129 families with Leber congenital amaurosis collected at the Zhongshan Ophthalmic Center, Guangzhou, China. Variants in CNGA3 and associated phenotypes, assessed by Sanger sequencing of CNGA3, bioinformatics of variants, and segregation analysis. Homozygous or compound heterozygous mutations in CNGA3, including 26 novel and 13 known mutations, were identified in 46 probands from 138 families with cone dystrophies, but none were found in any of the probands from 129 families with Leber congenital amaurosis. The 46 probands with CNGA3 mutations could be further classified as likely having achromatopsia (18 probands) and cone-rod dystrophies (28 probands) based on electroretinographic recordings. Analysis of family members in 17 of 46 families demonstrated good segregation of the disease with the CNGA3 mutations. To our knowledge, this study is the first systemic analysis of CNGA3 in Chinese patients and expands the mutational spectrum and associated phenotypes. Our results suggest that CNGA3 mutations are a common cause of cone-rod dystrophies and achromatopsia in the Chinese population. These data indicate that CNGA3-associated cone dystrophies may be a common form of early-onset severe retinal dystrophies. Therapeutic potential such as gene therapy targeting this gene may benefit some children with early-onset severe retinal dystrophies.