@article {505, title = {FAM92A Underlies Nonsyndromic Postaxial Polydactyly in Humans and an Abnormal Limb and Digit Skeletal Phenotype in Mice.}, journal = {J Bone Miner Res}, volume = {34}, year = {2019}, month = {2019 Feb}, pages = {375-386}, abstract = {

Polydactyly is a common congenital anomaly of the hand and foot. Postaxial polydactyly (PAP) is characterized by one or more posterior or postaxial digits. In a Pakistani family with autosomal recessive nonsyndromic postaxial polydactyly type A (PAPA), we performed genomewide genotyping, linkage analysis, and exome and Sanger sequencing. Exome sequencing revealed a homozygous nonsense variant (c.478C>T, p.[Arg160*]) in the FAM92A gene within the mapped region on 8q21.13-q24.12 that segregated with the PAPA phenotype. We found that FAM92A is expressed in the developing mouse limb and E11.5 limb bud including the progress zone and the apical ectodermal ridge, where it strongly localizes at the cilia level, suggesting an important role in limb patterning. The identified variant leads to a loss of the FAM92A/Chibby1 complex that is crucial for ciliogenesis and impairs the recruitment and the colocalization of FAM92A with Chibby1 at the base of the cilia. In addition, we show that Fam92a homozygous mice also exhibit an abnormal digit morphology, including metatarsal osteomas and polysyndactyly, in addition to distinct abnormalities on the deltoid tuberosity of their humeri. In conclusion, we present a new nonsyndromic PAPA ciliopathy due to a loss-of-function variant in FAM92A. {\textcopyright} 2018 American Society for Bone and Mineral Research.

}, issn = {1523-4681}, doi = {10.1002/jbmr.3594}, author = {Schrauwen, Isabelle and Giese, Arnaud Pj and Aziz, Abdul and Lafont, David Tino and Chakchouk, Imen and Santos-Cortez, Regie Lyn P and Lee, Kwanghyuk and Acharya, Anushree and Khan, Falak Sher and Ullah, Asmat and Nickerson, Deborah A and Bamshad, Michael J and Ali, Ghazanfar and Riazuddin, Saima and Ansar, Muhammad and Ahmad, Wasim and Ahmed, Zubair M and Leal, Suzanne M} } @article {549, title = {Global genetic insight contributed by consanguineous Pakistani families segregating hearing loss.}, journal = {Hum Mutat}, volume = {40}, year = {2019}, month = {2019 Jan}, pages = {53-72}, abstract = {

Consanguineous Pakistani pedigrees segregating deafness have contributed decisively to the discovery of 31 of the 68 genes associated with nonsyndromic autosomal recessive hearing loss (HL) worldwide. In this study, we utilized genome-wide genotyping, Sanger and exome sequencing to identify 163 DNA variants in 41 previously reported HL genes segregating in 321 Pakistani families. Of these, 70 (42.9\%) variants identified in 29 genes are novel. As expected from genetic studies of disorders segregating in consanguineous families, the majority of affected individuals (94.4\%) are homozygous for HL-associated variants, with the other variants being compound heterozygotes. The five most common HL genes in the Pakistani population are SLC26A4, MYO7A, GJB2, CIB2 and HGF, respectively. Our study provides a profile of the genetic etiology of HL in Pakistani families, which will allow for the development of more efficient genetic diagnostic tools, aid in accurate genetic counseling, and guide application of future gene-based therapies. These findings are also valuable in interpreting pathogenicity of variants that are potentially associated with HL in individuals of all ancestries. The Pakistani population, and its infrastructure for studying human genetics, will continue to be valuable to gene discovery for HL and other inherited disorders.

}, issn = {1098-1004}, doi = {10.1002/humu.23666}, author = {Richard, Elodie M and Santos-Cortez, Regie Lyn P and Faridi, Rabia and Rehman, Atteeq U and Lee, Kwanghyuk and Shahzad, Mohsin and Acharya, Anushree and Khan, Asma A and Imtiaz, Ayesha and Chakchouk, Imen and Takla, Christina and Abbe, Izoduwa and Rafeeq, Maria and Liaqat, Khurram and Chaudhry, Taimur and Bamshad, Michael J and Nickerson, Deborah A and Schrauwen, Isabelle and Khan, Shaheen N and Morell, Robert J and Zafar, Saba and Ansar, Muhammad and Ahmed, Zubair M and Ahmad, Wasim and Riazuddin, Sheikh and Friedman, Thomas B and Leal, Suzanne M and Riazuddin, Saima} } @article {660, title = {Identification of CACNA1D variants associated with sinoatrial node dysfunction and deafness in additional Pakistani families reveals a clinical significance.}, journal = {J Hum Genet}, volume = {64}, year = {2019}, month = {2019 Feb}, pages = {153-160}, abstract = {

Sinoatrial node dysfunction and deafness (SANDD) syndrome is rare and characterized by a low heart beat and severe-to-profound deafness. Additional features include fatigue, dizziness, and episodic syncope. The sinoatrial node (SAN) drives heart automaticity and continuously regulates heart rate. The CACNA1D gene encoding the Ca1.3 protein expressed in inner hair cells, atria and SAN, induces loss-of-function in channel activity and underlies SANDD. To date, only one variant c.1208_1209insGGG:p.(G403_V404insG) has been reported for SANDD syndrome. We studied five Pakistani families with SANDD and characterized a new missense variant p.(A376V) in CACNA1D in one family, and further characterized the founder variant p.(G403_V404insG) in four additional pedigrees. We show that affected individuals in the four families which segregate p.(G403_V404insG) share a 1.03 MB haplotype on 3p21.1 suggesting they share a common distant ancestor. In conclusion, we identified new and known variants in CACNA1D in five Pakistani families with SANDD. This study is of clinical importance as the CACNA1D founder variant is only observed in families from the Khyber Pakhtunkhwa (KPK) province, in Pakistan. Therefore, screening patients with congenital deafness for SAN dysfunction in this province could ensure adequate follow-up and prevent cardiac failure associated with SAN.

}, keywords = {Adolescent, Calcium Channels, L-Type, Deafness, Female, Heart Diseases, Humans, Male, Mutation, Pakistan, Pedigree, Prognosis, Sinoatrial Node}, issn = {1435-232X}, doi = {10.1038/s10038-018-0542-8}, author = {Liaqat, Khurram and Schrauwen, Isabelle and Raza, Syed Irfan and Lee, Kwanghyuk and Hussain, Shabir and Chakchouk, Imen and Nasir, Abdul and Acharya, Anushree and Abbe, Izoduwa and Umair, Muhammad and Ansar, Muhammad and Ullah, Irfan and Shah, Khadim and Bamshad, Michael J and Nickerson, Deborah A and Ahmad, Wasim and Leal, Suzanne M} } @article {652, title = {Variants in KIAA0825 underlie autosomal recessive postaxial polydactyly.}, journal = {Hum Genet}, volume = {138}, year = {2019}, month = {2019 Jun}, pages = {593-600}, abstract = {

Postaxial polydactyly (PAP) is a common limb malformation that often leads to cosmetic and functional complications. Molecular evaluation of polydactyly can serve as a tool to elucidate genetic and signaling pathways that regulate limb development, specifically, the anterior-posterior specification of the limb. To date, only five genes have been identified for nonsyndromic PAP: FAM92A, GLI1, GLI3, IQCE and ZNF141. In this study, two Pakistani multiplex consanguineous families with autosomal recessive nonsyndromic PAP were clinically and molecularly evaluated. From both pedigrees, a DNA sample from an affected member underwent exome sequencing. In each family, we identified a segregating frameshift (c.591dupA [p.(Q198Tfs*21)]) and nonsense variant (c.2173A > T [p.(K725*)]) in KIAA0825 (also known as C5orf36). Although KIAA0825 encodes a protein of unknown function, it has been demonstrated that its murine ortholog is expressed during limb development. Our data contribute to the establishment of a catalog of genes important in limb patterning, which can aid in diagnosis and obtaining a better understanding of the biology of polydactyly.

}, keywords = {Animals, Consanguinity, Family Health, Female, Fingers, Genes, Recessive, Genetic Predisposition to Disease, Genotype, Humans, Intracellular Signaling Peptides and Proteins, Male, Mice, Inbred C57BL, Mutation, Pedigree, Phenotype, Polydactyly, Toes, Whole Exome Sequencing}, issn = {1432-1203}, doi = {10.1007/s00439-019-02000-0}, author = {Ullah, Irfan and Kakar, Naseebullah and Schrauwen, Isabelle and Hussain, Shabir and Chakchouk, Imen and Liaqat, Khurram and Acharya, Anushree and Wasif, Naveed and Santos-Cortez, Regie Lyn P and Khan, Saadullah and Aziz, Abdul and Lee, Kwanghyuk and Couthouis, Julien and Horn, Denise and Kragesteen, Bj{\o}rt K and Spielmann, Malte and Thiele, Holger and Nickerson, Deborah A and Bamshad, Michael J and Gitler, Aaron D and Ahmad, Jamil and Ansar, Muhammad and Borck, Guntram and Ahmad, Wasim and Leal, Suzanne M} } @article {512, title = {Confirmation of the Role of DHX38 in the Etiology of Early-Onset Retinitis Pigmentosa.}, journal = {Invest Ophthalmol Vis Sci}, volume = {59}, year = {2018}, month = {2018 09 04}, pages = {4552-4557}, abstract = {

Purpose: Retinitis pigmentosa (RP) is a genetically heterogeneous trait with autosomal-recessive (ar) inheritance underlying 50\% of genetic disease cases. Sixty-one arRP genes have been identified, and recently, DHX38 has been reported as a potential candidate gene for arRP with only a single family reported with a variant of unknown significance. We identified a missense variant in DHX38 that co-segregates with the arRP phenotype in two Pakistani families confirming the involvement of DHX38 in the etiology of early-onset RP.

Methods: Exome sequencing was performed using two DNA samples from affected members of Pakistani families (MA88 and MA157) with early onset arRP. Sanger sequencing of DNA samples from all family members confirmed the segregation of candidate variant within both families.

Results: A novel missense DHX38 variant c.971G>A; p.(Arg324Gln) was identified which segregates with the arRP phenotype and yielded a logarithm of the odds (LOD) score of 5.0 and 4.3 for families MA88 and MA157, respectively. This variant is predicted to be conserved and deleterious by several bioinformatics tools.

Conclusions: We identified a second deleterious DHX38 variant that segregates with arRP in two families, providing additional evidence that DHX38 is involved in RP etiology. DHX38 encodes for pre-mRNA splicing factor PRP16, which is important in catalyzing pre-mRNA splicing.

}, keywords = {Adolescent, Adult, Cataract, Computational Biology, DEAD-box RNA Helicases, Female, Genes, Recessive, Genetic Association Studies, Genetic Linkage, Humans, Male, Mutation, Missense, Nucleotide Mapping, Ophthalmoscopy, Pedigree, Retinitis Pigmentosa, RNA Splicing Factors, Sequence Analysis, DNA, Whole Exome Sequencing, Young Adult}, issn = {1552-5783}, doi = {10.1167/iovs.18-23849}, author = {Latif, Zahid and Chakchouk, Imen and Schrauwen, Isabelle and Lee, Kwanghyuk and Santos-Cortez, Regie Lyn P and Abbe, Izoduwa and Acharya, Anushree and Jarral, Afeefa and Ali, Imran and Ullah, Ehsan and Khan, Muhammad Nasim and Ali, Ghazanfar and Tahir, Tufail Hussain and Bamshad, Michael J and Nickerson, Deborah A and Ahmad, Wasim and Ansar, Muhammad and Leal, Suzanne M} } @article {626, title = {LTBP3 Pathogenic Variants Predispose Individuals to Thoracic Aortic Aneurysms and Dissections.}, journal = {Am J Hum Genet}, volume = {102}, year = {2018}, month = {2018 04 05}, pages = {706-712}, abstract = {

The major diseases affecting the thoracic aorta are aneurysms and acute dissections, and pathogenic variants in 11 genes are confirmed to lead to heritable thoracic aortic disease. However, many families in which multiple members have thoracic aortic disease do not have alterations in the known aortopathy genes. Genes highly expressed in the aorta were assessed for rare variants in exome sequencing data from such families, and compound rare heterozygous variants (p.Pro45Argfs25 and p.Glu750) in LTBP3 were identified in affected members of one family. A homozygous variant (p.Asn678_Gly681delinsThrCys) that introduces an additional cysteine into an epidermal growth factor (EGF)-like domain in the corresponding protein, latent TGF-β binding protein (LTBP-3), was identified in a second family. Individuals with compound heterozygous or homozygous variants in these families have aneurysms and dissections of the thoracic aorta, as well as aneurysms of the abdominal aorta and other arteries, along with dental abnormalities and short stature. Heterozygous carriers of the p.Asn678_Gly681delinsThrCys variant have later onset of thoracic aortic disease, as well as dental abnormalities. In these families, LTBP3 variants segregated with thoracic aortic disease with a combined LOD score of 3.9. Additionally, heterozygous rare LTBP3 variants were found in individuals with early onset of acute aortic dissections, and some of these variants disrupted LTBP-3 levels or EGF-like domains. When compared to wild-type mice, Ltbp3 mice have enlarged aortic roots and ascending aortas. In summary, homozygous LTBP3 pathogenic variants predispose individuals to thoracic aortic aneurysms and dissections, along with the previously described skeletal and dental abnormalities.

}, keywords = {Adult, Aged, 80 and over, Aneurysm, Dissecting, Animals, Aortic Aneurysm, Thoracic, Blood Pressure, Female, Genetic Predisposition to Disease, Homozygote, Humans, Latent TGF-beta Binding Proteins, Male, Mice, Middle Aged, Mutation, Pedigree}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2018.03.002}, author = {Guo, Dong-Chuan and Regalado, Ellen S and Pinard, Amelie and Chen, Jiyuan and Lee, Kwanghyuk and Rigelsky, Christina and Zilberberg, Lior and Hostetler, Ellen M and Aldred, Micheala and Wallace, Stephanie E and Prakash, Siddharth K and Leal, Suzanne M and Bamshad, Michael J and Nickerson, Deborah A and Natowicz, Marvin and Rifkin, Daniel B and Milewicz, Dianna M} } @article {498, title = {Novel candidate genes and variants underlying autosomal recessive neurodevelopmental disorders with intellectual disability.}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Sep}, pages = {735-752}, abstract = {

Identification of Mendelian genes for neurodevelopmental disorders using exome sequencing to study autosomal recessive (AR) consanguineous pedigrees has been highly successful. To identify causal variants for syndromic and non-syndromic intellectual disability (ID), exome sequencing was performed using DNA samples from 22 consanguineous Pakistani families with ARID, of which 21 have additional phenotypes including microcephaly. To aid in variant identification, homozygosity mapping and linkage analysis were performed. DNA samples from affected family member(s) from every pedigree underwent exome sequencing. Identified rare damaging exome variants were tested for co-segregation with ID using Sanger sequencing. For seven ARID families, variants were identified in genes not previously associated with ID, including: EI24, FXR1 and TET3 for which knockout mouse models have brain defects; and CACNG7 and TRAPPC10 where cell studies suggest roles in important neural pathways. For two families, the novel ARID genes CARNMT1 and GARNL3 lie within previously reported ID microdeletion regions. We also observed homozygous variants in two ID candidate genes, GRAMD1B and TBRG1, for which each has been previously reported in a single family. An additional 14 families have homozygous variants in established ID genes, of which 11 variants are novel. All ARID genes have increased expression in specific structures of the developing and adult human brain and 91\% of the genes are differentially expressed in utero or during early childhood. The identification of novel ARID candidate genes and variants adds to the knowledge base that is required to further understand human brain function and development.

}, keywords = {Adult, Consanguinity, Family, Female, Genes, Recessive, Genetic Markers, Humans, Intellectual Disability, Male, Middle Aged, Mutation, Neurodevelopmental Disorders, Pedigree}, issn = {1432-1203}, doi = {10.1007/s00439-018-1928-6}, author = {Santos-Cortez, Regie Lyn P and Khan, Valeed and Khan, Falak Sher and Mughal, Zaib-Un-Nisa and Chakchouk, Imen and Lee, Kwanghyuk and Rasheed, Memoona and Hamza, Rifat and Acharya, Anushree and Ullah, Ehsan and Saqib, Muhammad Arif Nadeem and Abbe, Izoduwa and Ali, Ghazanfar and Hassan, Muhammad Jawad and Khan, Saadullah and Azeem, Zahid and Ullah, Irfan and Bamshad, Michael J and Nickerson, Deborah A and Schrauwen, Isabelle and Ahmad, Wasim and Ansar, Muhammad and Leal, Suzanne M} } @article {623, title = {A novel homozygous variant in BMPR1B underlies acromesomelic dysplasia Hunter-Thompson type.}, journal = {Ann Hum Genet}, volume = {82}, year = {2018}, month = {2018 May}, pages = {129-134}, abstract = {

Acromesomelic dysplasia is genetically heterogeneous group of skeletal disorders characterized by short stature and acromelia and mesomelia of limbs. Acromesomelic dysplasia segregates in an autosomal recessive pattern and is caused by biallelic sequence variants in three genes (NPR2, GDF5, and BMPR1B). A consanguineous family of Pakistani origin segregating a subtype of acromesomelic dysplasia called Hunter-Thompson was clinically and genetically evaluated. Genotyping of microsatellite markers and linkage analysis revealed a 7.78 Mb homozygous region on chromosome 4q22.3, which harbors BMPR1B. Sequence analysis of the gene revealed a novel homozygous missense variant (c.1190T~>~G, p.Met397Arg) that segregates with the disease phenotype within the family and produced a Logarithm of odds (LOD) score of 3.9 with the disease phenotype. This study reports on the first familial case of acromesomelic dysplasia Hunter-Thompson type. It is also the first report of BMPR1B underlying the etiology of acromesomelic dysplasia Hunter-Thompson type.

}, issn = {1469-1809}, doi = {10.1111/ahg.12233}, author = {Ullah, Asmat and Umair, Muhammad and Muhammad, Dost and Bilal, Muhammad and Lee, Kwanghyuk and Leal, Suzanne M and Ahmad, Wasim} } @article {632, title = {Sequence variants in nine different genes underlying rare skin disorders in 10 consanguineous families.}, journal = {Int J Dermatol}, volume = {56}, year = {2017}, month = {2017 Dec}, pages = {1406-1413}, abstract = {

BACKGROUND: Genodermatoses represent genetic anomalies of skin tissues including hair follicles, sebaceous glands, eccrine glands, nails, and teeth. Ten consanguineous families segregating various genodermatosis phenotypes were investigated in the present study.

METHODS: Homozygosity mapping, exome, and Sanger sequencing were employed to search for the disease-causing variants in the 10 families.

RESULTS: Exome sequencing identified seven homozygous sequence variants in different families, including: c.27delT in FERMT1; c.836delA in ABHD5; c.2453C>T in ERCC5; c.5314C>T in COL7A1; c.1630C>T in ALOXE3; c.502C>T in PPOX; and c.10G>T in ALDH3A2. Sanger sequencing revealed three homozygous variants: c.1718~+~2A>G in FERMT1; c.10459A>T in FLG; and c.92delT in the KRT14 genes as the underlying genetic cause of skin phenotypes.

CONCLUSION: This study supports the use of exome sequencing as a powerful, efficient tool for identifying genes that underlie rare monogenic skin disorders.

}, keywords = {1-Acylglycerol-3-Phosphate O-Acyltransferase, Aldehyde Oxidoreductases, Blister, Collagen Type VII, Consanguinity, DNA Mutational Analysis, DNA-Binding Proteins, Endonucleases, Epidermolysis Bullosa, Epidermolysis Bullosa Dystrophica, Epidermolysis Bullosa Simplex, Exome, Female, Flavoproteins, Homozygote, Humans, Ichthyosiform Erythroderma, Congenital, Ichthyosis Vulgaris, Ichthyosis, Lamellar, INDEL Mutation, Intermediate Filament Proteins, Keratin-14, Lipid Metabolism, Inborn Errors, Lipoxygenase, Male, Membrane Proteins, Mitochondrial Proteins, Muscular Diseases, Neoplasm Proteins, Nuclear Proteins, Pedigree, Periodontal Diseases, Phenotype, Photosensitivity Disorders, Porphyria, Variegate, Protoporphyrinogen Oxidase, Rare Diseases, Sjogren-Larsson Syndrome, Skin Diseases, Genetic, Transcription Factors, Xeroderma Pigmentosum}, issn = {1365-4632}, doi = {10.1111/ijd.13778}, author = {Shah, Khadim and Mehmood, Sabba and Jan, Abid and Abbe, Izoduwa and Hussain Ali, Raja and Khan, Anwar and Chishti, Muhammad S and Lee, Kwanghyuk and Ahmad, Farooq and Ansar, Muhammad and Shahzad, Shaheen and Nickerson, Deborah A and Bamshad, Michael J and Coucke, Paul J and Santos-Cortez, Regie L P and Spritz, Richard A and Leal, Suzanne M and Ahmad, Wasim} } @article {89, title = {Autosomal-Recessive Hearing Impairment Due to Rare Missense Variants within S1PR2.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 Feb 04}, pages = {331-8}, abstract = {

The sphingosine-1-phosphate receptors (S1PRs) are a well-studied class of transmembrane G protein-coupled sphingolipid receptors that mediate multiple cellular processes. However, S1PRs have not been previously reported to be involved in the genetic etiology of human traits. S1PR2 lies within the autosomal-recessive nonsyndromic hearing impairment (ARNSHI) locus DFNB68 on 19p13.2. From exome sequence data we identified two pathogenic S1PR2 variants, c.323G>C (p.Arg108Pro) and c.419A>G (p.Tyr140Cys). Each of these variants co-segregates with congenital profound hearing impairment in consanguineous Pakistani families with maximum LOD scores of 6.4 for family DEM4154 and 3.3 for family PKDF1400. Neither S1PR2 missense variant was reported among \~{}120,000 chromosomes in the Exome Aggregation Consortium database, in 76 unrelated Pakistani exomes, or in 720 Pakistani control chromosomes. Both DNA variants affect highly conserved residues of S1PR2 and are predicted to be damaging by multiple bioinformatics tools. Molecular modeling predicts that these variants affect binding of sphingosine-1-phosphate (p.Arg108Pro) and G protein docking (p.Tyr140Cys). In the previously reported S1pr2(-/-) mice, stria vascularis abnormalities, organ of Corti degeneration, and profound hearing loss were~observed. Additionally, hair cell defects were seen in both knockout mice and morphant zebrafish. Family PKDF1400 presents with ARNSHI, which is consistent with the lack of gross malformations in S1pr2(-/-) mice, whereas family DEM4154 has lower limb malformations in addition to hearing loss. Our findings suggest the possibility of developing therapies against hair cell damage (e.g., from ototoxic drugs) through targeted stimulation of S1PR2.

}, keywords = {Amino Acid Sequence, Asian Continental Ancestry Group, Chromosomes, Human, Pair 19, Exome, Genes, Recessive, Hearing Loss, Humans, Lod Score, Logistic Models, Lysophospholipids, Models, Molecular, Molecular Sequence Data, Mutation, Missense, Pedigree, Phenotype, Receptors, Lysosphingolipid, Sphingosine}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2015.12.004}, author = {Santos-Cortez, Regie Lyn P and Faridi, Rabia and Rehman, Atteeq U and Lee, Kwanghyuk and Ansar, Muhammad and Wang, Xin and Morell, Robert J and Isaacson, Rivka and Belyantseva, Inna A and Dai, Hang and Acharya, Anushree and Qaiser, Tanveer A and Muhammad, Dost and Ali, Rana Amjad and Shams, Sulaiman and Hassan, Muhammad Jawad and Shahzad, Shaheen and Raza, Syed Irfan and Bashir, Zil-E-Huma and Smith, Joshua D and Nickerson, Deborah A and Bamshad, Michael J and Riazuddin, Sheikh and Ahmad, Wasim and Friedman, Thomas B and Leal, Suzanne M} } @article {100, title = {Expansion of the spectrum of ITGB6-related disorders to adolescent alopecia, dentogingival abnormalities and intellectual disability.}, journal = {Eur J Hum Genet}, volume = {24}, year = {2016}, month = {2016 08}, pages = {1223-7}, abstract = {

Alopecia with mental retardation (APMR) is a very rare disorder. In this study, we report on a consanguineous Pakistani family (AP91) with mild-to-moderate intellectual disability, adolescent alopecia and dentogingival abnormalities. Using homozygosity mapping, linkage analysis and exome sequencing, we identified a novel rare missense variant c.898G>A (p.(Glu300Lys)) in ITGB6, which co-segregates with the phenotype within the family and is predicted to be deleterious. Structural modeling shows that Glu300 lies in the β-propeller domain, and is surrounded by several residues that are important for heterodimerization with α integrin. Previous studies showed that ITGB6 variants can cause amelogenesis imperfecta in humans, but patients from family AP91 who are homozygous for the c.898G>A variant present with neurological and dermatological features, indicating a role for ITGB6 beyond enamel formation. Our study demonstrates that a rare deleterious variant within ITGB6 causes not only dentogingival anomalies but also intellectual disability and alopecia.

}, keywords = {Adolescent, Adult, Alopecia, Child, Female, Humans, Integrin beta Chains, Intellectual Disability, Male, Mutation, Missense, Pedigree, Phenotype, Protein Domains, Syndrome, Tooth Abnormalities}, issn = {1476-5438}, doi = {10.1038/ejhg.2015.260}, author = {Ansar, Muhammad and Jan, Abid and Santos-Cortez, Regie Lyn P and Wang, Xin and Suliman, Muhammad and Acharya, Anushree and Habib, Rabia and Abbe, Izoduwa and Ali, Ghazanfar and Lee, Kwanghyuk and Smith, Joshua D and Nickerson, Deborah A and Shendure, Jay and Bamshad, Michael J and Ahmad, Wasim and Leal, Suzanne M} } @article {83, title = {Mitral regurgitation as a phenotypic manifestation of nonphotosensitive trichothiodystrophy due to a splice variant in MPLKIP.}, journal = {BMC Med Genet}, volume = {17}, year = {2016}, month = {2016 Feb 16}, pages = {13}, abstract = {

BACKGROUND: Nonphotosensitive trichothiodystrophy (TTDN) is a rare autosomal recessive disorder of neuroectodermal origin. The condition is marked by hair abnormalities, intellectual impairment, nail dystrophies and susceptibility to infections but with no UV sensitivity.

METHODS: We identified three consanguineous Pakistani families with varied TTDN features and used homozygosity mapping, linkage analysis, and Sanger and exome sequencing in order to identify pathogenic variants. Haplotype analysis was performed and haplotype age estimated. A splicing assay was used to validate the effect of the MPLKIP splice variant on expression.

RESULTS: Affected individuals from all families exhibit several TTDN features along with a heart-specific feature, i.e. mitral regurgitation. Exome sequencing in the probands from families ED168 and ED241 identified a homozygous splice mutation c.339 + 1G > A within MPLKIP. The same splice variant co-segregates with TTDN in a third family ED210. The MPLKIP splice variant was not found in public databases, e.g. the Exome Aggregation Consortium, and in unrelated Pakistani controls. Functional analysis of the splice variant confirmed intron retention, which leads to protein truncation and loss of a phosphorylation site. Haplotype analysis identified a 585.1-kb haplotype which includes the MPLKIP variant, supporting the existence of a founder haplotype that is estimated to be 25,900 years old.

CONCLUSION: This study extends the allelic and phenotypic spectra of MPLKIP-related TTDN, to include a splice variant that causes cardiomyopathy as part of the TTDN phenotype.

}, keywords = {Adaptor Proteins, Signal Transducing, Adolescent, Adult, Alleles, Asian Continental Ancestry Group, Child, Cloning, Molecular, Exome, Female, Genetic Linkage, Haplotypes, HEK293 Cells, Homozygote, Humans, Introns, Male, Mitral Valve Insufficiency, Pakistan, Pedigree, Phenotype, Polymorphism, Single Nucleotide, RNA Splicing, Sequence Analysis, DNA, Trichothiodystrophy Syndromes, Young Adult}, issn = {1471-2350}, doi = {10.1186/s12881-016-0275-5}, author = {Shah, Khadim and Ali, Raja Hussain and Ansar, Muhammad and Lee, Kwanghyuk and Chishti, Muhammad Salman and Abbe, Izoduwa and Li, Biao and Smith, Joshua D and Nickerson, Deborah A and Shendure, Jay and Coucke, Paul J and Steyaert, Wouter and Bamshad, Michael J and Santos-Cortez, Regie Lyn P and Leal, Suzanne M and Ahmad, Wasim} } @article {42, title = {Mutational Spectrum of MYO15A and the Molecular Mechanisms of DFNB3 Human Deafness.}, journal = {Hum Mutat}, volume = {37}, year = {2016}, month = {2016 10}, pages = {991-1003}, abstract = {

Deafness in humans is a common neurosensory disorder and is genetically heterogeneous. Across diverse ethnic groups, mutations of MYO15A at the DFNB3 locus appear to be the third or fourth most common cause of autosomal-recessive, nonsyndromic deafness. In 49 of the 67 exons of MYO15A, there are currently 192 recessive mutations identified, including 14 novel mutations reported here. These mutations are distributed uniformly across MYO15A with one enigmatic exception; the alternatively spliced giant exon 2, encoding 1,233 residues, has 17 truncating mutations but no convincing deafness-causing missense mutations. MYO15A encodes three distinct isoform classes, one of which is 395 kDa (3,530 residues), the largest member of the myosin superfamily of molecular motors. Studies of Myo15 mouse models that recapitulate DFNB3 revealed two different pathogenic mechanisms of hearing loss. In the inner ear, myosin 15 is necessary both for the development and the long-term maintenance of stereocilia, mechanosensory sound-transducing organelles that extend from the apical surface of hair cells. The goal of this Mutation Update is to provide a comprehensive review of mutations and functions of MYO15A.

}, keywords = {Alternative Splicing, Animals, Deafness, Disease Models, Animal, Ear, Inner, Exons, Gene Expression Regulation, Developmental, Humans, Mice, Mutation, Myosins, Stereocilia}, issn = {1098-1004}, doi = {10.1002/humu.23042}, author = {Rehman, Atteeq U and Bird, Jonathan E and Faridi, Rabia and Shahzad, Mohsin and Shah, Sujay and Lee, Kwanghyuk and Khan, Shaheen N and Imtiaz, Ayesha and Ahmed, Zubair M and Riazuddin, Saima and Santos-Cortez, Regie Lyn P and Ahmad, Wasim and Leal, Suzanne M and Riazuddin, Sheikh and Friedman, Thomas B} } @article {116, title = {Novel mutations in the genes TGM1 and ALOXE3 underlying autosomal recessive congenital ichthyosis.}, journal = {Int J Dermatol}, volume = {55}, year = {2016}, month = {2016 May}, pages = {524-30}, abstract = {

BACKGROUND: Ichthyoses are clinically characterized by scaling or hyperkeratosis of the skin or both. It can be an isolated condition limited to the skin or appear secondarily with involvement of other cutaneous or systemic abnormalities.

METHODS: The present study investigated clinical and molecular characterization of three consanguineous families (A, B, C) segregating two different forms of autosomal recessive congenital ichthyosis (ARCI). Linkage in three consanguineous families (A, B, C) segregating two different forms of ARCI was searched by typing microsatellite and single nucleotide polymorphism marker analysis. Sequencing of the two genes TGM1 and ALOXE3 was performed by the dideoxy chain termination method.

RESULTS: Genome-wide linkage analysis established linkage in family A to TGM1 gene on chromosome 14q11 and in families B and C to ALOXE3 gene on chromosome 17p13. Subsequently, sequencing of these genes using samples from affected family members led to the identification of three novel mutations: a missense variant p.Trp455Arg in TGM1 (family A); a nonsense variant p.Arg140* in ALOXE3 (family B); and a complex rearrangement in ALOXE3 (family C).

CONCLUSION: The present study further extends the spectrum of mutations in the two genes involved in causing ARCI. Characterizing the clinical spectrum resulting from mutations in the TGM1 and ALOXE3 genes will improve diagnosis and may direct clinical care of the family members.

}, keywords = {Adolescent, Chromosomes, Human, Pair 14, Chromosomes, Human, Pair 17, Codon, Nonsense, Consanguinity, Female, Gene Rearrangement, Genotype, Humans, Ichthyosiform Erythroderma, Congenital, Ichthyosis, Lamellar, Lipoxygenase, Male, Mutation, Missense, Pakistan, Pedigree, Phenotype, Transglutaminases, Young Adult}, issn = {1365-4632}, doi = {10.1111/ijd.12950}, author = {Ullah, Rahim and Ansar, Muhammad and Durrani, Zaka Ullah and Lee, Kwanghyuk and Santos-Cortez, Regie Lyn P and Muhammad, Dost and Ali, Mahboob and Zia, Muhammad and Ayub, Muhammad and Khan, Suliman and Smith, Josh D and Nickerson, Deborah A and Shendure, Jay and Bamshad, Michael and Leal, Suzanne M and Ahmad, Wasim} } @article {204, title = {Challenges and solutions for gene identification in the presence of familial locus heterogeneity.}, journal = {Eur J Hum Genet}, volume = {23}, year = {2015}, month = {2015 Sep}, pages = {1207-15}, abstract = {

Next-generation sequencing (NGS) of exomes and genomes has accelerated the identification of genes involved in Mendelian phenotypes. However, many NGS studies fall short of identifying causal variants, with estimates for success rates as low as 25\% for uncovering the pathological variant underlying disease etiology. An important reason for such failures is familial locus heterogeneity, where within a single pedigree causal variants in two or more genes underlie Mendelian trait etiology. As examples of intra- and inter-sibship familial locus heterogeneity, we present 10 consanguineous Pakistani families segregating hearing impairment due to homozygous variants in two different hearing impairment genes and a European-American pedigree in which hearing impairment is caused by four variants in three different genes. We have identified 41 additional pedigrees with syndromic and nonsyndromic hearing impairment for which a single previously reported hearing impairment gene has been identified but only segregates with the phenotype in a subset of affected pedigree members. We estimate that locus heterogeneity occurs in 15.3\% (95\% confidence interval: 11.9\%, 19.9\%) of the families in our collection. We demonstrate novel approaches to apply linkage analysis and homozygosity mapping (for autosomal recessive consanguineous pedigrees), which can be used to detect locus heterogeneity using either NGS or SNP array data. Results from linkage analysis and homozygosity mapping can also be used to group sibships or individuals most likely to be segregating the same causal variants and thereby increase the success rate of gene identification.

}, keywords = {Asian Continental Ancestry Group, Calcium-Binding Proteins, Chromosome Mapping, Connexin 26, Connexins, Consanguinity, European Continental Ancestry Group, Female, Genes, Recessive, Genetic Heterogeneity, Genetic Linkage, Genetic Loci, Genetic Predisposition to Disease, Genome, Human, Genotype, Hearing Loss, Hepatocyte Growth Factor, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Male, Membrane Transport Proteins, Mutation, Pedigree, Phenotype, Sulfate Transporters}, issn = {1476-5438}, doi = {10.1038/ejhg.2014.266}, author = {Rehman, Atteeq U and Santos-Cortez, Regie Lyn P and Drummond, Meghan C and Shahzad, Mohsin and Lee, Kwanghyuk and Morell, Robert J and Ansar, Muhammad and Jan, Abid and Wang, Xin and Aziz, Abdul and Riazuddin, Saima and Smith, Joshua D and Wang, Gao T and Ahmed, Zubair M and Gul, Khitab and Shearer, A Eliot and Smith, Richard J H and Shendure, Jay and Bamshad, Michael J and Nickerson, Deborah A and Hinnant, John and Khan, Shaheen N and Fisher, Rachel A and Ahmad, Wasim and Friderici, Karen H and Riazuddin, Sheikh and Friedman, Thomas B and Wilch, Ellen S and Leal, Suzanne M} } @article {173, title = {COPA mutations impair ER-Golgi transport and cause hereditary autoimmune-mediated lung disease and arthritis.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 Jun}, pages = {654-60}, abstract = {

Unbiased genetic studies have uncovered surprising molecular mechanisms in human cellular immunity and autoimmunity. We performed whole-exome sequencing and targeted sequencing in five families with an apparent mendelian syndrome of autoimmunity characterized by high-titer autoantibodies, inflammatory arthritis and interstitial lung disease. We identified four unique deleterious variants in the COPA gene (encoding coatomer subunit α) affecting the same functional domain. Hypothesizing that mutant COPA leads to defective intracellular transport via coat protein complex I (COPI), we show that COPA variants impair binding to proteins targeted for retrograde Golgi-to-ER transport. Additionally, expression of mutant COPA results in ER stress and the upregulation of cytokines priming for a T helper type 17 (TH17) response. Patient-derived CD4(+) T cells also demonstrate significant skewing toward a TH17 phenotype that is implicated in autoimmunity. Our findings uncover an unexpected molecular link between a vesicular transport protein and a syndrome of autoimmunity manifested by lung and joint disease.

}, keywords = {Amino Acid Sequence, Arthritis, Autoimmune Diseases, Child, Preschool, Coatomer Protein, Endoplasmic Reticulum, Endoplasmic Reticulum Stress, Female, Genetic Association Studies, Genetic Predisposition to Disease, Golgi Apparatus, HEK293 Cells, Humans, Infant, Lod Score, Lung Diseases, Interstitial, Male, Molecular Sequence Data, Pedigree, Protein Transport}, issn = {1546-1718}, doi = {10.1038/ng.3279}, author = {Watkin, Levi B and Jessen, Birthe and Wiszniewski, Wojciech and Vece, Timothy J and Jan, Max and Sha, Youbao and Thamsen, Maike and Santos-Cortez, Regie L P and Lee, Kwanghyuk and Gambin, Tomasz and Forbes, Lisa R and Law, Christopher S and Stray-Pedersen, Asbj{\o}rg and Cheng, Mickie H and Mace, Emily M and Anderson, Mark S and Liu, Dongfang and Tang, Ling Fung and Nicholas, Sarah K and Nahmod, Karen and Makedonas, George and Canter, Debra L and Kwok, Pui-Yan and Hicks, John and Jones, Kirk D and Penney, Samantha and Jhangiani, Shalini N and Rosenblum, Michael D and Dell, Sharon D and Waterfield, Michael R and Papa, Feroz R and Muzny, Donna M and Zaitlen, Noah and Leal, Suzanne M and Gonzaga-Jauregui, Claudia and Boerwinkle, Eric and Eissa, N Tony and Gibbs, Richard A and Lupski, James R and Orange, Jordan S and Shum, Anthony K} } @article {150, title = {A homozygous missense variant in type I keratin KRT25 causes autosomal recessive woolly hair.}, journal = {J Med Genet}, volume = {52}, year = {2015}, month = {2015 Oct}, pages = {676-80}, abstract = {

BACKGROUND: Woolly hair (WH) is a hair abnormality that is primarily characterised by tightly curled hair with abnormal growth.

METHODS: In two unrelated consanguineous Pakistani families with non-syndromic autosomal recessive (AR) WH, homozygosity mapping and linkage analysis identified a locus within 17q21.1-q22, which contains the type I keratin gene cluster. A DNA sample from an affected individual from each family underwent exome sequencing.

RESULTS: A homozygous missense variant c.950T>C (p.(Leu317Pro)) within KRT25 segregated with ARWH in both families, and has a combined maximum two-point LOD score of 7.9 at ϴ=0. The KRT25 variant is predicted to result in disruption of the second α-helical rod domain and the entire protein structure, thus possibly interfering with heterodimerisation of K25 with type II keratins within the inner root sheath (IRS) of the hair follicle and the medulla of the hair shaft.

CONCLUSIONS: Our findings implicate a novel gene involved in human hair abnormality, and are consistent with the curled, fragile hair found in mice with Krt25 mutations, and further support the role of IRS-specific type I keratins in hair follicle development and maintenance of hair texture.

}, keywords = {Child, Child, Preschool, Consanguinity, Hair, Hair Diseases, Humans, Keratins, Type I, Male, Mutation, Missense, Pakistan, Pedigree, Sequence Analysis, DNA}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2015-103255}, author = {Ansar, Muhammad and Raza, Syed Irfan and Lee, Kwanghyuk and Shahi, Shamim and Acharya, Anushree and Dai, Hang and Smith, Joshua D and Shendure, Jay and Bamshad, Michael J and Nickerson, Deborah A and Santos-Cortez, Regie Lyn P and Ahmad, Wasim and Leal, Suzanne M} } @article {157, title = {Mutation of ATF6 causes autosomal recessive achromatopsia.}, journal = {Hum Genet}, volume = {134}, year = {2015}, month = {2015 Sep}, pages = {941-50}, abstract = {

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.

}, keywords = {Activating Transcription Factor 6, Adolescent, Animals, Asian Continental Ancestry Group, Color Vision Defects, Consanguinity, DNA Mutational Analysis, Exome, Female, Frameshift Mutation, Genotyping Techniques, Homozygote, Humans, Limit of Detection, Male, Mice, Mice, Inbred C57BL, Pakistan, Pedigree, Phenotype, Retina, Signal Transduction}, issn = {1432-1203}, doi = {10.1007/s00439-015-1571-4}, author = {Ansar, Muhammad and Santos-Cortez, Regie Lyn P and Saqib, Muhammad Arif Nadeem and Zulfiqar, Fareeha and Lee, Kwanghyuk and Ashraf, Naeem Mahmood and Ullah, Ehsan and Wang, Xin and Sajid, Sundus and Khan, Falak Sher and Amin-ud-Din, Muhammad and Smith, Joshua D and Shendure, Jay and Bamshad, Michael J and Nickerson, Deborah A and Hameed, Abdul and Riazuddin, Saima and Ahmed, Zubair M and Ahmad, Wasim and Leal, Suzanne M} } @article {267, title = {Adenylate cyclase 1 (ADCY1) mutations cause recessive hearing impairment in humans and defects in hair cell function and hearing in zebrafish.}, journal = {Hum Mol Genet}, volume = {23}, year = {2014}, month = {2014 Jun 15}, pages = {3289-98}, abstract = {

Cyclic AMP (cAMP) production, which is important for mechanotransduction within the inner ear, is catalyzed by adenylate cyclases (AC). However, knowledge of the role of ACs in hearing is limited. Previously, a novel autosomal recessive non-syndromic hearing impairment locus DFNB44 was mapped to chromosome 7p14.1-q11.22 in a consanguineous family from Pakistan. Through whole-exome sequencing of DNA samples from hearing-impaired family members, a nonsense mutation c.3112C>T (p.Arg1038*) within adenylate cyclase 1 (ADCY1) was identified. This stop-gained mutation segregated with hearing impairment within the family and was not identified in ethnically matched controls or within variant databases. This mutation is predicted to cause the loss of 82 amino acids from the carboxyl tail, including highly conserved residues within the catalytic domain, plus a calmodulin-stimulation defect, both of which are expected to decrease enzymatic efficiency. Individuals who are homozygous for this mutation had symmetric, mild-to-moderate mixed hearing impairment. Zebrafish adcy1b morphants had no FM1-43 dye uptake and lacked startle response, indicating hair cell dysfunction and gross hearing impairment. In the mouse, Adcy1 expression was observed throughout inner ear development and maturation. ADCY1 was localized to the cytoplasm of supporting cells and hair cells of the cochlea and vestibule and also to cochlear hair cell nuclei and stereocilia. Ex vivo studies in COS-7 cells suggest that the carboxyl tail of ADCY1 is essential for localization to actin-based microvilli. These results demonstrate that ADCY1 has an evolutionarily conserved role in hearing and that cAMP signaling is important to hair cell function within the inner ear.

}, keywords = {Adenylyl Cyclases, Animals, Cercopithecus aethiops, Codon, Nonsense, COS Cells, Cyclic AMP, Cytoplasm, Ear, Inner, Female, Hair Cells, Auditory, Hearing Loss, Humans, Labyrinth Supporting Cells, Male, Mice, Zebrafish}, issn = {1460-2083}, doi = {10.1093/hmg/ddu042}, author = {Santos-Cortez, Regie Lyn P and Lee, Kwanghyuk and Giese, Arnaud P and Ansar, Muhammad and Amin-ud-Din, Muhammad and Rehn, Kira and Wang, Xin and Aziz, Abdul and Chiu, Ilene and Hussain Ali, Raja and Smith, Joshua D and Shendure, Jay and Bamshad, Michael and Nickerson, Deborah A and Ahmed, Zubair M and Ahmad, Wasim and Riazuddin, Saima and Leal, Suzanne M} } @article {274, title = {Mutations in TBC1D24, a gene associated with epilepsy, also cause nonsyndromic deafness DFNB86.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Jan 02}, pages = {144-52}, abstract = {

Inherited deafness is clinically and genetically heterogeneous. We recently mapped DFNB86, a locus associated with nonsyndromic deafness, to chromosome 16p. In this study, whole-exome sequencing was performed with genomic DNA from affected individuals from three large consanguineous families in which markers linked to DFNB86 segregate with profound deafness. Analyses of these data revealed homozygous mutation c.208G>T (p.Asp70Tyr) or c.878G>C (p.Arg293Pro) in TBC1D24 as the underlying cause of deafness in the three families. Sanger sequence analysis of TBC1D24 in an additional large family in which deafness segregates with DFNB86 identified the c.208G>T (p.Asp70Tyr) substitution. These mutations affect TBC1D24 amino acid residues that are conserved in orthologs ranging from fruit fly to human. Neither variant was observed in databases of single-nucleotide variants or in 634 chromosomes from ethnically matched control subjects. TBC1D24 in the mouse inner ear was immunolocalized predominantly to spiral ganglion neurons, indicating that DFNB86 deafness might be an auditory neuropathy spectrum disorder. Previously, six recessive mutations in TBC1D24 were reported to cause seizures (hearing loss was not reported) ranging in severity from epilepsy with otherwise normal development to epileptic encephalopathy resulting in childhood death. Two of our four families in which deafness segregates with mutant alleles of TBC1D24 were available for neurological examination. Cosegregation of epilepsy and deafness was not observed in these two families. Although the causal relationship between genotype and phenotype is not presently understood, our findings, combined with published data, indicate that recessive alleles of TBC1D24 can cause either epilepsy or nonsyndromic deafness.

}, keywords = {Alleles, Amino Acid Sequence, Carrier Proteins, Chromosomes, Human, Pair 16, Consanguinity, Deafness, Epilepsy, Exome, Exons, Female, Genes, Recessive, Genetic Loci, Genome-Wide Association Study, Heterozygote, Homozygote, Humans, Male, Molecular Sequence Data, Mutation, Pakistan, Pedigree, Phenotype, Polymorphism, Single Nucleotide, RNA, Messenger, Sequence Analysis, DNA}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.12.004}, author = {Rehman, Atteeq U and Santos-Cortez, Regie Lyn P and Morell, Robert J and Drummond, Meghan C and Ito, Taku and Lee, Kwanghyuk and Khan, Asma A and Basra, Muhammad Asim R and Wasif, Naveed and Ayub, Muhammad and Ali, Rana A and Raza, Syed I and Nickerson, Deborah A and Shendure, Jay and Bamshad, Michael and Riazuddin, Saima and Billington, Neil and Khan, Shaheen N and Friedman, Penelope L and Griffith, Andrew J and Ahmad, Wasim and Riazuddin, Sheikh and Leal, Suzanne M and Friedman, Thomas B} } @article {299, title = {Mutations in KARS, encoding lysyl-tRNA synthetase, cause autosomal-recessive nonsyndromic hearing impairment DFNB89.}, journal = {Am J Hum Genet}, volume = {93}, year = {2013}, month = {2013 Jul 11}, pages = {132-40}, abstract = {

Previously, DFNB89, a locus associated with autosomal-recessive nonsyndromic hearing impairment (ARNSHI), was mapped to chromosomal region 16q21-q23.2 in three unrelated, consanguineous Pakistani families. Through whole-exome sequencing of a hearing-impaired individual from each family, missense mutations were identified at highly conserved residues of lysyl-tRNA synthetase (KARS): the c.1129G>A (p.Asp377Asn) variant was found in one family, and the c.517T>C (p.Tyr173His) variant was found in the other two families. Both variants were predicted to be damaging by multiple bioinformatics tools. The two variants both segregated with the nonsyndromic-hearing-impairment phenotype within the three families, and neither mutation was identified in ethnically matched controls or within variant databases. Individuals homozygous for KARS mutations had symmetric, severe hearing impairment across all frequencies but did not show evidence of auditory or limb neuropathy. It has been demonstrated that KARS is expressed in hair cells of zebrafish, chickens, and mice. Moreover, KARS has strong localization to the spiral ligament region of the cochlea, as well as to Deiters{\textquoteright} cells, the sulcus epithelium, the basilar membrane, and the surface of the spiral limbus. It is hypothesized that KARS variants affect aminoacylation in inner-ear cells by interfering with binding activity to tRNA or p38 and with tetramer formation. The identification of rare KARS variants in ARNSHI-affected families defines a gene that is associated with ARNSHI.

}, keywords = {Animals, Case-Control Studies, Chickens, Cochlea, Computational Biology, Consanguinity, Female, Genetic Linkage, Hair Cells, Auditory, Inner, Haplotypes, Hearing Loss, Homozygote, Humans, Lysine-tRNA Ligase, Male, Mice, Mutation, Missense, Pedigree, Transfer RNA Aminoacylation, Zebrafish}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.05.018}, author = {Santos-Cortez, Regie Lyn P and Lee, Kwanghyuk and Azeem, Zahid and Antonellis, Patrick J and Pollock, Lana M and Khan, Saadullah and Andrade-Elizondo, Paula B and Chiu, Ilene and Adams, Mark D and Basit, Sulman and Smith, Joshua D and Nickerson, Deborah A and McDermott, Brian M and Ahmad, Wasim and Leal, Suzanne M} } @article {308, title = {Perrault syndrome is caused by recessive mutations in CLPP, encoding a mitochondrial ATP-dependent chambered protease.}, journal = {Am J Hum Genet}, volume = {92}, year = {2013}, month = {2013 Apr 04}, pages = {605-13}, abstract = {

Perrault syndrome is a genetically and clinically heterogeneous autosomal-recessive condition characterized by sensorineural hearing loss and ovarian failure. By a combination of linkage analysis, homozygosity mapping, and exome sequencing in three families, we identified mutations in CLPP as the likely cause of this phenotype. In each family, affected individuals were homozygous for a different pathogenic CLPP allele: c.433A>C (p.Thr145Pro), c.440G>C (p.Cys147Ser), or an experimentally demonstrated splice-donor-site mutation, c.270+4A>G. CLPP, a component of a mitochondrial ATP-dependent proteolytic complex, is a highly conserved endopeptidase encoded by CLPP and forms an element of the evolutionarily ancient mitochondrial unfolded-protein response (UPR(mt)) stress signaling pathway. Crystal-structure modeling suggests that both substitutions would alter the structure of the CLPP barrel chamber that captures unfolded proteins and exposes them to proteolysis. Together with the previous identification of mutations in HARS2, encoding mitochondrial histidyl-tRNA synthetase, mutations in CLPP expose dysfunction of mitochondrial protein homeostasis as a cause of Perrault syndrome.

}, keywords = {Adenosine Triphosphate, Adolescent, Adult, ATP-Dependent Proteases, Endopeptidase Clp, Exome, Female, Genes, Recessive, Gonadal Dysgenesis, 46,XX, Hearing Loss, Sensorineural, Homozygote, Humans, In Situ Hybridization, Male, Mitochondria, Mutation, Pedigree, Phenotype, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.02.013}, author = {Jenkinson, Emma M and Rehman, Atteeq U and Walsh, Tom and Clayton-Smith, Jill and Lee, Kwanghyuk and Morell, Robert J and Drummond, Meghan C and Khan, Shaheen N and Naeem, Muhammad Asif and Rauf, Bushra and Billington, Neil and Schultz, Julie M and Urquhart, Jill E and Lee, Ming K and Berry, Andrew and Hanley, Neil A and Mehta, Sarju and Cilliers, Deirdre and Clayton, Peter E and Kingston, Helen and Smith, Miriam J and Warner, Thomas T and Black, Graeme C and Trump, Dorothy and Davis, Julian R E and Ahmad, Wasim and Leal, Suzanne M and Riazuddin, Sheikh and King, Mary-Claire and Friedman, Thomas B and Newman, William G} }