Mapping autosomal recessive intellectual disability: combined microarray and exome sequencing identifies 26 novel candidate genes in 192 consanguineous families.

Mol Psychiatry. 2017 Apr 11;:

Authors: Harripaul R, Vasli N, Mikhailov A, Rafiq MA, Mittal K, Windpassinger C, Sheikh TI, Noor A, Mahmood H, Downey S, Johnson M, Vleuten K, Bell L, Ilyas M, Khan FS, Khan V, Moradi M, Ayaz M, Naeem F, Heidari A, Ahmed I, Ghadami S, Agha Z, Zeinali S, Qamar R, Mozhdehipanah H, John P, Mir A, Ansar M, French L, Ayub M, Vincent JB

Abstract
Approximately 1% of the global population is affected by intellectual disability (ID), and the majority receive no molecular diagnosis. Previous studies have indicated high levels of genetic heterogeneity, with estimates of more than 2500 autosomal ID genes, the majority of which are autosomal recessive (AR). Here, we combined microarray genotyping, homozygosity-by-descent (HBD) mapping, copy number variation (CNV) analysis, and whole exome sequencing (WES) to identify disease genes/mutations in 192 multiplex Pakistani and Iranian consanguineous families with non-syndromic ID. We identified definite or candidate mutations (or CNVs) in 51% of families in 72 different genes, including 26 not previously reported for ARID. The new ARID genes include nine with loss-of-function mutations (ABI2, MAPK8, MPDZ, PIDD1, SLAIN1, TBC1D23, TRAPPC6B, UBA7 and USP44), and missense mutations include the first reports of variants in BDNF or TET1 associated with ID. The genes identified also showed overlap with de novo gene sets for other neuropsychiatric disorders. Transcriptional studies showed prominent expression in the prenatal brain. The high yield of AR mutations for ID indicated that this approach has excellent clinical potential and should inform clinical diagnostics, including clinical whole exome and genome sequencing, for populations in which consanguinity is common. As with other AR disorders, the relevance will also apply to outbred populations.Molecular Psychiatry advance online publication, 11 April 2017; doi:10.1038/mp.2017.60.

PMID: 28397838 [PubMed - as supplied by publisher]

Postmortem genetic testing should be recommended in sudden cardiac death cases due to thoracic aortic dissection.

Int J Legal Med. 2017 Apr 08;:

Authors: Gago-Díaz M, Ramos-Luis E, Zoppis S, Zorio E, Molina P, Braza-Boïls A, Giner J, Sobrino B, Amigo J, Blanco-Verea A, Carracedo Á, Brion M

Abstract
BACKGROUND: Acute thoracic aortic dissections and ruptures, the main life-threatening complications of the corresponding aneurysms, are an important cause of sudden cardiac death. Despite the usefulness of the molecular diagnosis of these conditions in the clinical setting, the corresponding forensic field remains largely unexplored. The main goal of this study was to explore and validate a new massive parallel sequencing candidate gene​ assay as a diagnostic tool for acute thoracic aortic dissection autopsy cases.
MATERIALS AND METHODS: Massive parallel sequencing of 22 thoracic aortic disease candidate genes performed in 17 cases of thoracic aortic dissection using AmpliSeq and Ion Proton technologies. Genetic variants were filtered by location, type, and frequency at the Exome Aggregation Consortium and an internal database and further classified based on the American College of Medical Genetics and Genomics (ACMG) recommendations published in 2015. All prioritized results were confirmed by traditional sequencing.
RESULTS: From the total of 10 potentially pathogenic genetic variants identified in 7 out of the 17 initial samples, 2 of them were further classified as pathogenic, 2 as likely pathogenic, 1 as possibly benign, and the remaining 5 as variants of uncertain significance, reaching a molecular autopsy yield of 23%, approximately.
CONCLUSIONS: This massive parallel sequencing candidate gene approach proved useful for the molecular autopsy of aortic dissection sudden cardiac death cases and should therefore be progressively incorporated into the forensic field, being especially beneficial for the anticipated diagnosis and risk stratification of any other family member at risk of developing the same condition.

PMID: 28391405 [PubMed - as supplied by publisher]

Identification of 2 Potentially Relevant Gene Mutations Involved in Strabismus Using Whole-Exome Sequencing.

Med Sci Monit. 2017 Apr 09;23:1719-1724

Authors: Min X, Fan H, Zhao G, Liu G

Abstract
BACKGROUND The etiology of strabismus has a genetic component. Our study aimed to localize the candidate causative gene mutant in a Chinese family with strabismus and to describe its underlying etiology. MATERIAL AND METHODS Genomic DNA was extracted from the affected individual and his parents in a Chinese pedigree with strabismus. The resulting exomes were sequenced by whole-exome sequencing. After variant calling and filtering, the candidate causative gene mutations were selected for the rarity and predicted damaging effect, which complied with the model of recessive disease transmission. RESULTS We examined a Chinese strabismus pedigree with the parents unaffected and 2 offspring affected. Whole-exome sequencing and bioinformatics filtering identified 2 variants including Abelson helper integration site 1 (AHI1) gene and nebulin (NEB) gene. The variant in the AHI1 gene, c.A3257G (p.E1086G), and the altered amino acid had a damaging effect on the encoded protein predicted by Polyphen2. Moreover, this change was located in the conserved SH3 domain of AHI1. Biallelic pathogenic variant in AHI1 gene can cause Joubert syndrome-related disorders with oculomotor apraxia characteristics. Additionally, c.A914G mutation was found in nebulin (NEB) gene. Therefore, we concluded that AHI1 c.3257A>G and NEB c.914 A>G were potential causal variants in this strabismus pedigree. CONCLUSIONS We detected an AHI1 homozygous mutation in the affected individual. Whole-exome sequencing is a powerful way to identify causally relevant genes, improving the understanding of this disorder.

PMID: 28391287 [PubMed - in process]

MYO15A splicing mutations in hearing loss: A review literature and report of a novel mutation.

Int J Pediatr Otorhinolaryngol. 2017 May;96:35-38

Authors: Motavaf M, Soveizi M, Maleki M, Mahdieh N

Abstract
Sensorineural hearing loss (SNHL) is the most prevalent genetic sensory defect in humans, affecting about 1 in 1000 newborns around the world. Non-syndromic SNHL accounts for nearly 70% of hereditary hearing loss and 80% of SNHL cases show an autosomal recessive mode of inheritance (ARNSHL). In the present study, we applied targeted-exome sequencing to a family with a single proband affected by congenital sensorineural hearing loss. 127 known genes were sequenced to find the causative mutation. One novel homozygous donor splice site mutation, c.4596 + 1G > A (IVS12 + 1G > A) was found in MYO15A gene. Analysis of this mutation within the family showed that the mutation segregates with hearing loss. New DNA sequencing technologies could lead to identification of the disease causing variants especially in highly heterogeneous disorders such as hearing loss.

PMID: 28390610 [PubMed - in process]

Myoepithelial carcinoma with RB1 mutation: remarkable chemosensitivity to carcinoma of unknown origin therapy.

BMC Cancer. 2017 Apr 08;17(1):250

Authors: Hoggard TM, Henderson-Jackson E, Bui MM, Caracciolo J, Teer JK, Yoder S, Binitie O, Gonzalez RJ, Brohl AS, Reed DR

Abstract
BACKGROUND: Myoepithelial carcinoma of soft tissue is a rare, malignant neoplasm that is morphologically and immunophenotypically similar to its counterpart in salivary gland. It demonstrates myoepithelial differentiation, possessing both epithelial and myogenic characteristics. Thought to be chemotherapy insensitive, the optimal treatment regimen of this tumor has yet to be established and only a select few cases in the literature discuss treatment efficacy in detail.
CASE PRESENTATION: Here we present a case of a young adult with metastatic myoepithelial carcinoma with an initial excellent response to systemic therapy utilizing carboplatin and paclitaxel with continued complete response after 3 years. The patient also underwent complete surgical excision and received adjuvant radiation to the primary site of disease. Exome sequencing revealed an inactivating mutation in RB1 which we believe to be the first such mutation to be reported in this cancer type.
CONCLUSIONS: Given increasing evidence suggesting RB1 loss is associated with responsiveness to conventional chemotherapies, particularly platinum-based regimens, we hypothesize that this genetic feature predisposed chemosensitivity in our patient's tumor.

PMID: 28390395 [PubMed - in process]

Familial Early-Onset Paget's Disease of Bone Associated with a Novel hnRNPA2B1 Mutation.

Calcif Tissue Int. 2017 Apr 07;:

Authors: Qi X, Pang Q, Wang J, Zhao Z, Wang O, Xu L, Mao J, Jiang Y, Li M, Xing X, Yu W, Asan, Xia W

Abstract
Paget disease of bone (PDB) is a common metabolic bone disease characterized by increased bone resorption and disorganized bone formation which affect single or multiple sites of bones. Although the exact cause of PDB is still controversial, genetic factors are considered to play an important role in PDB. Several genes involved in the differentiation or function of osteoclast were shown to be associated with PDB or related syndrome such as SQSTM1, TNFRSF11A, TNFRSF11B, and ZNF687. Multisystem proteinopathy (MSP), a newly proposed syndrome including inclusion body myopathy (IBM), PDB, frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS), is mainly caused by mutation in VCP gene. In 2013, a new casual gene for MSP was identified as hnRNPA2B1 gene. This may partly account for the inherited PDB traits which is however negative for mutation in already known causative PDB genes. We investigated a Chinese family with multiple affected individuals with PDB, but none of the members showed symptoms of IBM, FTD, or ALS. Three patients were evaluated clinically, biochemically, and radiographically. To screen for the responsible mutation, whole-exome sequencing was conducted in the proband, another patient, as well as a normal individual from the family. This revealed a novel heterozygous missense mutation of hnRNPA2B1 gene (c.929C>T, p. P310L) in the two patients which was then verified in all affected individuals. We describe here a novel missense mutation in hnRNPA2B1 gene in a large pedigree affected with PDB with members who do not present other manifestations of multisystem proteinopathy, such as IBM, FTD, and ALS.

PMID: 28389692 [PubMed - as supplied by publisher]

Large Scale Analysis of Variation in the Insulin-like Growth Factor Family in Humans Reveals Rare Disease Links and Common Polymorphisms.

J Biol Chem. 2017 Apr 07;:

Authors: Rotwein P

Abstract
The insulin-like growth factors IGF1 and IGF2 are closely related proteins that are essential for normal growth and development in humans and other species and play critical roles in many physiological and patho-physiological processes. IGF actions are mediated by trans-membrane receptors and modulated by IGF binding proteins. The importance of IGF actions in human physiology is strengthened by the rarity of inactivating mutations in their genes, and by the devastating impact caused by such mutations on normal development and somatic growth. Large-scale genome sequencing has the potential to provide new insights into human variation and disease susceptibility. Toward this end the availability of DNA sequence data from 60,706 people through the Exome Aggregation Consortium has prompted the analyses presented here. Results reveal a broad range of potential missense and other alterations in the coding regions of every IGF family gene but the vast majority of predicted changes were uncommon. The total number of different alleles detected per gene in the population varied over an ~15-fold range, from 57 for IGF1 to 872 for IGF2R, although when corrected for protein length, the rate ranged from 0.22 to 0.59 changes/codon among the 11 genes evaluated. Previously characterized disease-causing mutations in IGF2, IGF1R, IGF2R, or IGFALS all were found in the general population, but with allele frequencies of < 1:30,000. A few new highly prevalent amino acid polymorphisms also were identified. Collectively, these data provide a wealth of opportunities to understand the intricacies of IGF signaling and action in both physiological and pathological contexts.

PMID: 28389567 [PubMed - as supplied by publisher]

A burden of rare variants in BMPR2 and KCNK3 contributes to a risk of familial pulmonary arterial hypertension.

BMC Pulm Med. 2017 Apr 07;17(1):57

Authors: Higasa K, Ogawa A, Terao C, Shimizu M, Kosugi S, Yamada R, Date H, Matsubara H, Matsuda F

Abstract
BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe lung disease with only few effective treatments available. Familial cases of PAH are usually recognized as an autosomal dominant disease, but incomplete penetrance of the disease makes it difficult to identify pathogenic variants in accordance with a Mendelian pattern of inheritance.
METHODS: To elucidate the complex genetic basis of PAH, we obtained whole exome- or genome-sequencing data of 17 subjects from 9 families with heritable PAH and applied gene-based association analysis with 9 index patients and 300 PAH-free controls.
RESULTS: A burden of rare variants in BMPR2 significantly contributed to the risk of the disease (p = 6.0 × 10(-8)). Eight of nine families carried four previously reported single nucleotide variants and four novel insertion/deletion variants in the gene. One of the novel variants was a large 6.5 kilobase-deletion. In the remaining one family, the patient carried a pathogenic variant in a member of potassium channels, KCNK3, which was the first replicative finding of channelopathy in an Asian population.
CONCLUSIONS: The variety of rare pathogenic variants suggests that gene-based association analysis using genome-wide sequencing data from increased number of samples is essential to tracing the genetic heterogeneity and developing an appropriate panel for genetic testing.

PMID: 28388887 [PubMed - in process]

A recognizable systemic connective tissue disorder with polyvalvular heart dystrophy and dysmorphism associated with TAB2 mutations.

Clin Genet. 2017 Apr 06;:

Authors: Ritelli M, Morlino S, Giacopuzzi E, Bernardini L, Torres B, Santoro G, Ravasio V, Chiarelli N, D'Angelantonio D, Novelli A, Grammatico P, Colombi M, Castori M

Abstract
Deletions encompassing TAK1-binding protein 2 (TAB2) associate with isolated and syndromic congenital heart defects. Rare missense variants are found in patients with a similar phenotype as well as in a single individual with frontometaphyseal dysplasia. We describe a family and an additional sporadic patient with polyvalvular heart disease, generalized joint hypermobility and related musculoskeletal complications, soft, velvety and hyperextensible skin, short limbs, hearing impairment, and facial dysmorphism. In the first family, whole exome sequencing disclosed the novel TAB2 c.1398dup (p.Thr467Tyrfs*6) variant that eliminates the C-terminal zinc finger domain essential for activation of TAK1 (TGFβ-activated kinase 1)-dependent signaling pathways. The sporadic case carryed a ~2 Mb de novo deletion including 28 genes also comprising TAB2. This study reveal an association between TAB2 mutations and a phenotype resembling Ehlers-Danlos syndrome with severe polyvalvular heart disease and subtle facial dysmorphism. Our findings support the existence of a wider spectrum of clinical phenotypes associated with TAB2 perturbations and emphasize the role of TAK1 signaling network in human development.

PMID: 28386937 [PubMed - as supplied by publisher]

Mutated PET117 causes complex IV deficiency and is associated with neurodevelopmental regression and medulla oblongata lesions.

Hum Genet. 2017 Apr 06;:

Authors: Renkema GH, Visser G, Baertling F, Wintjes LT, Wolters VM, van Montfrans J, de Kort GA, Nikkels PG, van Hasselt PM, van der Crabben SN, Rodenburg RJ

Abstract
The genetic basis of the many progressive, multi systemic, mitochondrial diseases that cause a lack of cellular ATP production is heterogeneous, with defects found both in the mitochondrial genome as well as in the nuclear genome. Many different mutations have been found in the genes encoding subunits of the enzyme complexes of the oxidative phosphorylation system. In addition, mutations in genes encoding proteins involved in the assembly of these complexes are known to cause mitochondrial disorders. Here we describe two sisters with a mitochondrial disease characterized by lesions in the medulla oblongata, as demonstrated by brain magnetic resonance imaging, and an isolated complex IV deficiency and reduced levels of individual complex IV subunits. Whole exome sequencing revealed a homozygous nonsense mutation resulting in a premature stop codon in the gene encoding Pet117, a small protein that has previously been predicted to be a complex IV assembly factor. PET117 has not been identified as a mitochondrial disease gene before. Lentiviral complementation of patient fibroblasts with wild-type PET117 restored the complex IV deficiency, proving that the gene defect is responsible for the complex IV deficiency in the patients, and indicating a pivotal role of this protein in the proper functioning of complex IV. Although previous studies had suggested a possible role of this protein in the insertion of copper into complex IV, studies in patient fibroblasts could not confirm this. This case presentation thus implicates mutations in PET117 as a novel cause of mitochondrial disease.

PMID: 28386624 [PubMed - as supplied by publisher]

Generalized verrucosis and abnormal T cell activation due to homozygous TAOK2 mutation.

J Dermatol Sci. 2017 Mar 27;:

Authors: Molho-Pessach V, Ramot Y, Mogilevsky M, Cohen-Daniel L, Eisenstein EM, Abu-Libdeh A, Siam I, Berger M, Karni R, Zlotogorski A

Abstract
BACKGROUND: Generalized verrucosis (GV) is a chronic and progressive cutaneous human papillomavirus (HPV) infection resulting in multiple warts and associated with acquired or genetic immune defects. We identified a consanguineous Arab family manifesting GV and recurrent bacterial and viral infections, in association with inflammatory bowel disease (IBD).
OBJECTIVE: To identify the mutated gene responsible for GV, recurrent infections and IBD, in this family.
METHODS: Flow cytometry of peripheral blood mononuclear cells was performed, as well as proliferation and cell cycle assays of T cells. Whole exome sequencing was utilized to detect candidate mutated genes, assuming an autosomal recessive mode of inheritance. Skin fibroblasts from a patient, the mother and control were incubated with sorbitol to detect the phosphorylation ability of TAOK2, and a clonogenic assay was performed to assess the survival and proliferative capacity of fibroblasts' colonies.
RESULTS: Despite normal immunophenotyping of T and B cells, T cell proliferation upon activation was impaired in a patient compared to a heterozygous family member and a control. Genetic analyses identified a rare homozygous missense variant, c.2098C>T (p.R700C) in the TAOK2 gene, segregating with the disease phenotype in the family. TAOK2 encodes the TAO2 kinase, a mitogen activated protein kinase kinase kinase (MAP3K) in the p38-MAPK cascade. The mutation is predicted to disrupt its normal folding and molecular interaction; however, no impairment was observed in TAOK2 kinase activity toward its downstream target, MEK3/6, in patient's fibroblasts. Despite this normal kinase activity, a noticeably higher survival/proliferation of patient's skin fibroblasts was found.
CONCLUSIONS: A mutation in TAOK2 appears to cause a novel form of primary immunodeficiency, characterized by an impaired T cell proliferation upon activation. This novel cause of GV gives further support to the importance of the p38-MAPK pathway in the immune response against HPV, and possibly also in the pathogenesis of IBD.

PMID: 28385331 [PubMed - as supplied by publisher]

Exome Sequence Analysis of 14 Families With High Myopia.

Invest Ophthalmol Vis Sci. 2017 Apr 01;58(4):1982-1990

Authors: Kloss BA, Tompson SW, Whisenhunt KN, Quow KL, Huang SJ, Pavelec DM, Rosenberg T, Young TL

Abstract
Purpose: To identify causal gene mutations in 14 families with autosomal dominant (AD) high myopia using exome sequencing.
Methods: Select individuals from 14 large Caucasian families with high myopia were exome sequenced. Gene variants were filtered to identify potential pathogenic changes. Sanger sequencing was used to confirm variants in original DNA, and to test for disease cosegregation in additional family members. Candidate genes and chromosomal loci previously associated with myopic refractive error and its endophenotypes were comprehensively screened.
Results: In 14 high myopia families, we identified 73 rare and 31 novel gene variants as candidates for pathogenicity. In seven of these families, two of the novel and eight of the rare variants were within known myopia loci. A total of 104 heterozygous nonsynonymous rare variants in 104 genes were identified in 10 out of 14 probands. Each variant cosegregated with affection status. No rare variants were identified in genes known to cause myopia or in genes closest to published genome-wide association study association signals for refractive error or its endophenotypes.
Conclusions: Whole exome sequencing was performed to determine gene variants implicated in the pathogenesis of AD high myopia. This study provides new genes for consideration in the pathogenesis of high myopia, and may aid in the development of genetic profiling of those at greatest risk for attendant ocular morbidities of this disorder.

PMID: 28384719 [PubMed - in process]

Candidate Gene Analysis Identifies Mutations in CYP1B1 and LTBP2 in Indian Families with Primary Congenital Glaucoma.

Genet Test Mol Biomarkers. 2017 Apr;21(4):252-258

Authors: Yang Y, Zhang L, Li S, Zhu X, Sundaresan P

Abstract
BACKGROUND: Primary congenital glaucoma (PCG) is a severe ocular disorder that presents early in life. Cytochrome P4501B1 (CYP1B1) and latent transforming growth factor-beta-binding protein 2 (LTBP2) are the most commonly mutated genes in PCG.
AIM: To investigate the causative genetic mutations in eight Indian families with PCG.
MATERIALS AND METHODS: Whole-exome sequencing was applied to analyze the genomic DNA samples from PCG probands. Sanger sequencing was utilized to confirm the identified mutations.
RESULTS: We identified four homozygous missense mutations (c.1405C>T, p.R469W; c.1397G>T, p.G466V; c.1198C>T, p.P400S; and c.1103G>A, p.R368H) in CYP1B1 and one nonsense mutation (c.2421G>A, p.W807X) in LTBP2 in eight Indian families. Among the five mutations identified, G466V in CYP1B1 and W807X in LTBP2 represent novel mutations.
CONCLUSIONS: Our study expands the mutational spectrum of PCG in the Indian population.

PMID: 28384041 [PubMed - in process]

Autozygosity reveals recessive mutations and novel mechanisms in dominant genes: implications in variant interpretation.

Genet Med. 2017 Apr 06;:

Authors: Monies D, Maddirevula S, Kurdi W, Alanazy MH, Alkhalidi H, Al-Owain M, Sulaiman RA, Faqeih E, Goljan E, Ibrahim N, Abdulwahab F, Hashem M, Abouelhoda M, Shaheen R, Arold ST, Alkuraya FS

Abstract
PURPOSE: The purpose of this study is to describe recessive alleles in strictly dominant genes. Identifying recessive mutations in genes for which only dominant disease or risk alleles have been reported can expand our understanding of the medical relevance of these genes both phenotypically and mechanistically. The Saudi population is enriched for autozygosity, which enhances the homozygous occurrence of alleles, including pathogenic alleles in genes that have been associated only with a dominant inheritance pattern.
METHODS: Exome sequencing of patients from consanguineous families with likely recessive phenotypes was performed. In one family, the genotype of the deceased children was inferred from their parents due to lack of available samples.
RESULTS: We describe the identification of 11 recessive variants (5 of which are reported here for the first time) in 11 genes for which only dominant disease or risk alleles have been reported. The observed phenotypes for these recessive variants were novel (e.g., FBN2-related myopathy and CSF1R-related brain malformation and osteopetrosis), typical (e.g., ACTG2-related visceral myopathy), or an apparently healthy state (e.g., PDE11A), consistent with the corresponding mouse knockout phenotypes.
CONCLUSION: Our results show that, in the era of genomic sequencing and "reverse phenotyping," recessive variants in dominant genes should not be dismissed based on perceived "incompatibility" with the patient's phenotype before careful consideration.Genet Med advance online publication 06 April 2017Genetics in Medicine (2017); doi:10.1038/gim.2017.22.

PMID: 28383543 [PubMed - as supplied by publisher]

A Dominant Mutation in Nuclear Receptor Interacting Protein 1 Causes Urinary Tract Malformations via Dysregulation of Retinoic Acid Signaling.

J Am Soc Nephrol. 2017 Apr 05;:

Authors: Vivante A, Mann N, Yonath H, Weiss AC, Getwan M, Kaminski MM, Bohnenpoll T, Teyssier C, Chen J, Shril S, van der Ven AT, Ityel H, Schmidt JM, Widmeier E, Bauer SB, Sanna-Cherchi S, Gharavi AG, Lu W, Magen D, Shukrun R, Lifton RP, Tasic V, Stanescu HC, Cavaillès V, Kleta R, Anikster Y, Dekel B, Kispert A, Lienkamp SS, Hildebrandt F

Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) are the most common cause of CKD in the first three decades of life. However, for most patients with CAKUT, the causative mutation remains unknown. We identified a kindred with an autosomal dominant form of CAKUT. By whole-exome sequencing, we identified a heterozygous truncating mutation (c.279delG, p.Trp93fs*) of the nuclear receptor interacting protein 1 gene (NRIP1) in all seven affected members. NRIP1 encodes a nuclear receptor transcriptional cofactor that directly interacts with the retinoic acid receptors (RARs) to modulate retinoic acid transcriptional activity. Unlike wild-type NRIP1, the altered NRIP1 protein did not translocate to the nucleus, did not interact with RARα, and failed to inhibit retinoic acid-dependent transcriptional activity upon expression in HEK293 cells. Notably, we also showed that treatment with retinoic acid enhanced NRIP1 binding to RARα RNA in situ hybridization confirmed Nrip1 expression in the developing urogenital system of the mouse. In explant cultures of embryonic kidney rudiments, retinoic acid stimulated Nrip1 expression, whereas a pan-RAR antagonist strongly reduced it. Furthermore, mice heterozygous for a null allele of Nrip1 showed a CAKUT-spectrum phenotype. Finally, expression and knockdown experiments in Xenopus laevis confirmed an evolutionarily conserved role for NRIP1 in renal development. These data indicate that dominant NRIP1 mutations can cause CAKUT by interference with retinoic acid transcriptional signaling, shedding light on the well documented association between abnormal vitamin A levels and renal malformations in humans, and suggest a possible gene-environment pathomechanism in this disease.

PMID: 28381549 [PubMed - as supplied by publisher]

RGR variants in different forms of retinal diseases: The undetermined role of truncation mutations.

Mol Med Rep. 2016 Nov;14(5):4811-4815

Authors: Li J, Xiao X, Li S, Jia X, Guo X, Zhang Q

Abstract
It has been previously reported that mutations in retinal G protein coupled receptor (RGR) are associated with retinitis pigmentosa. The present study aims to systemically analyze the potential role of variants of RGR in retinal diseases. Variants in coding regions and splice sites of RGR were selected from a whole exome sequencing dataset of 820 probands with various forms of genetic ocular diseases. Potential variants of RGR were further confirmed by Sanger sequencing and analyzed in available family members. Clinical data was reviewed for patients with RGR variants. As a result, a total of five variants in RGR were detected in six probands with different types of ocular diseases. Of the five variants, two were novel heterozygous truncation variations, c.266C>A (p.S89*) and c.722_723delCC (p.S241Yfs*29), identified in two probands with high myopia and confirmed by Sanger sequencing. Segregation analysis on available family members demonstrated p.S89* and p.S241Yfs*29 were also present in unaffected relatives. The other three variants of RGR were heterozygous missense variants randomly occurring in patients with different genetic ocular diseases. No homozygous or compound heterozygous variants were detected. The results of the present study suggested that the heterozygous truncation variants in RGR were less likely to be pathogenic. Further studies are expected to evaluate the pathogenicity of variants in RGR.

PMID: 27748892 [PubMed - indexed for MEDLINE]

The first Japanese case of leukodystrophy with ovarian failure arising from novel compound heterozygous AARS2 mutations.

J Hum Genet. 2016 Oct;61(10):899-902

Authors: Hamatani M, Jingami N, Tsurusaki Y, Shimada S, Shimojima K, Asada-Utsugi M, Yoshinaga K, Uemura N, Yamashita H, Uemura K, Takahashi R, Matsumoto N, Yamamoto T

Abstract
Even now, only a portion of leukodystrophy patients are correctly diagnosed, though various causative genes have been identified. In the present report, we describe a case of adult-onset leukodystrophy in a woman with ovarian failure. By whole-exome sequencing, a compound heterozygous mutation consisting of NM_020745.3 (AARS2_v001):c.1145C>A and NM_020745.3 (AARS2_v001):c.2255+1G>A was identified. Neither of the mutations has been previously reported, and this is the first report of alanyl-transfer RNA synthetase 2 mutation in Asia. We anticipate that further studies of the molecular basis of leukodystrophy will provide insight into its pathogenesis and hopefully lead to sophisticated diagnostic and treatment strategies.

PMID: 27251004 [PubMed - indexed for MEDLINE]

De novo MEIS2 mutation causes syndromic developmental delay with persistent gastro-esophageal reflux.

J Hum Genet. 2016 Sep;61(9):835-8

Authors: Fujita A, Isidor B, Piloquet H, Corre P, Okamoto N, Nakashima M, Tsurusaki Y, Saitsu H, Miyake N, Matsumoto N

Abstract
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.

PMID: 27225850 [PubMed - indexed for MEDLINE]

A PDE3A mutation in familial hypertension and brachydactyly syndrome.

J Hum Genet. 2016 Aug;61(8):701-3

Authors: Boda H, Uchida H, Takaiso N, Ouchi Y, Fujita N, Kuno A, Hata T, Nagatani A, Funamoto Y, Miyata M, Yoshikawa T, Kurahashi H, Inagaki H

Abstract
Hypertension and brachydactyly syndrome (HTNB) with short stature is an autosomal-dominant disorder. Mutations in the PDE3A gene located at 12p12.2-p11.2 were recently identified in HTNB families. We found a novel heterozygous missense mutation c.1336T>C in exon 4 of the PDE3A gene in a Japanese family with multiple HTNB patients. This mutation was found to be completely linked to the family members who inherited this condition. The mutation, resulting in p.Ser446Pro, was located within the cluster region of reported mutations. This mutation may also affect the phosphodiesterase activity of PDE3A to reduce the cyclic AMP level in the cell and thereby influencing the development of limbs and the function of the cardiovascular system.

PMID: 27053290 [PubMed - indexed for MEDLINE]

De novo KCNH1 mutations in four patients with syndromic developmental delay, hypotonia and seizures.

J Hum Genet. 2016 May;61(5):381-7

Authors: Fukai R, Saitsu H, Tsurusaki Y, Sakai Y, Haginoya K, Takahashi K, Hubshman MW, Okamoto N, Nakashima M, Tanaka F, Miyake N, Matsumoto N

Abstract
The voltage-gated Kv10.1 potassium channel, also known as ether-a-go-go-related gene 1, encoded by KCNH1 (potassium voltage-gated channel, subfamily H (eag related), member 1) is predominantly expressed in the central nervous system. Recently, de novo missense KCNH1 mutations have been identified in six patients with Zimmermann-Laband syndrome and in four patients with Temple-Baraitser syndrome. These syndromes were historically considered distinct. Here we report three de novo missense KCNH1 mutations in four patients with syndromic developmental delay and epilepsy. Two novel KCNH1 mutations (p.R357Q and p.R357P), found in three patients, were located at the evolutionally highly conserved arginine in the channel voltage-sensor domain (S4). Another mutation (p.G496E) was found in the channel pore domain (S6) helix, which acts as a hinge in activation gating and mainly conducts non-inactivating outward potassium current. A previously reported p.G496R mutation was shown to produce no voltage-dependent outward current in CHO cells, suggesting that p.G496E may also disrupt the proper function of the Kv channel pore. Our report confirms that KCNH1 mutations are associated with syndromic neurodevelopmental disorder, and also support the functional importance of the S4 domain.

PMID: 26818738 [PubMed - indexed for MEDLINE]