@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 {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 {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 {152, title = {Rare A2ML1 variants confer susceptibility to otitis media.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 Aug}, pages = {917-20}, abstract = {

A duplication variant within the middle ear-specific gene A2ML1 cosegregates with otitis media in an indigenous Filipino pedigree (LOD score = 7.5 at reduced penetrance) and lies within a founder haplotype that is also shared by 3 otitis-prone European-American and Hispanic-American children but is absent in non-otitis-prone children and >62,000 next-generation sequences. We identified seven additional A2ML1 variants in six otitis-prone children. Collectively, our studies support a role for A2ML1 in the pathophysiology of otitis media.

}, keywords = {alpha-Macroglobulins, Animals, Base Sequence, Child, Cochlea, Exome, Family Health, Female, Gene Duplication, Gene Frequency, Genetic Predisposition to Disease, Genotype, Haplotypes, Humans, Male, Mice, Inbred C57BL, Models, Molecular, Otitis Media, Pedigree, Principal Component Analysis, Protein Conformation, Sequence Analysis, DNA}, issn = {1546-1718}, doi = {10.1038/ng.3347}, author = {Santos-Cortez, Regie Lyn P and Chiong, Charlotte M and Reyes-Quintos, Ma Rina T and Tantoco, Ma Leah C and Wang, Xin and Acharya, Anushree and Abbe, Izoduwa and Giese, Arnaud P and Smith, Joshua D and Allen, E Kaitlynn and Li, Biao and Cutiongco-de la Paz, Eva Maria and Garcia, Marieflor Cristy and Llanes, Erasmo Gonzalo D V and Labra, Patrick John and Gloria-Cruz, Teresa Luisa I and Chan, Abner L and Wang, Gao T and Daly, Kathleen A and Shendure, Jay and Bamshad, Michael J and Nickerson, Deborah A and Patel, Janak A and Riazuddin, Saima and Sale, Michele M and Chonmaitree, Tasnee and Ahmed, Zubair M and Abes, Generoso T 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 {279, title = {Rare-variant extensions of the transmission disequilibrium test: application to autism exome sequence data.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Jan 02}, pages = {33-46}, abstract = {

Many population-based rare-variant (RV) association tests, which aggregate variants across a region, have been developed to analyze sequence data. A drawback of analyzing population-based data is that it is difficult to adequately control for population substructure and admixture, and spurious associations can occur. For RVs, this problem can be substantial, because the spectrum of rare variation can differ greatly between populations. A solution is to analyze parent-child trio data, by using the transmission disequilibrium test (TDT), which is robust to population substructure and admixture. We extended the TDT to test for RV associations using four commonly used methods. We demonstrate that for all RV-TDT methods, using proper analysis strategies, type I error is well-controlled even when there are high levels of population substructure or admixture. For trio data, unlike for population-based data, RV allele-counting association methods will lead to inflated type I errors. However type I errors can be properly controlled by obtaining p values empirically through haplotype permutation. The power of the RV-TDT methods was evaluated and compared to the analysis of case-control data with a number of genetic and disease models. The RV-TDT was also used to analyze exome data from 199 Simons Simplex Collection autism trios and an association was observed with variants in ABCA7. Given the problem of adequately controlling for population substructure and admixture in RV association studies and the growing number of sequence-based trio studies, the RV-TDT is extremely beneficial to elucidate the involvement of RVs in the etiology of complex traits.

}, keywords = {Alleles, Autistic Disorder, Computer Simulation, Exome, Gene Frequency, Genetic Association Studies, Genetic Predisposition to Disease, Genetic Variation, Haplotypes, Humans, Linkage Disequilibrium, Models, Genetic, Phenotype, Sequence Analysis, DNA}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.11.021}, author = {He, Zongxiao and O{\textquoteright}Roak, Brian J and Smith, Joshua D and Wang, Gao and Hooker, Stanley and Santos-Cortez, Regie Lyn P and Li, Biao and Kan, Mengyuan and Krumm, Nik and Nickerson, Deborah A and Shendure, Jay and Eichler, Evan E and Leal, Suzanne M} }