@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 {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 {485, title = {A variant in LMX1A causes autosomal recessive severe-to-profound hearing impairment.}, journal = {Hum Genet}, volume = {137}, year = {2018}, month = {2018 Jul}, pages = {471-478}, abstract = {

Hereditary hearing impairment is a common sensory disorder that is genetically and phenotypically heterogeneous. In this study, we used a homozygosity mapping and exome sequencing strategy to study a consanguineous Pakistani family with autosomal recessive severe-to-profound hearing impairment. This led to the identification of a missense variant (p.Ile369Thr) in the LMX1A gene affecting a conserved residue in the C-terminus of the protein, which was predicted damaging by an in silico bioinformatics analysis. The p.Ile369Thr variant disrupts several C-terminal and homeodomain residue interactions, including an interaction with homeodomain residue p.Val241 that was previously found to be involved in autosomal dominant progressive HI. LIM-homeodomain factor Lmx1a is expressed in the inner ear through development, shows a progressive restriction to non-sensory epithelia, and is important in the separation of the sensory and non-sensory domains in the inner ear. Homozygous Lmx1a mutant mice (Dreher) are deaf with dysmorphic ears with an abnormal morphogenesis and fused and misshapen sensory organs; however, computed tomography performed on a hearing-impaired family member did not reveal any cochleovestibular malformations. Our results suggest that LMX1A is involved in both human autosomal recessive and dominant sensorineural hearing impairment.

}, keywords = {Adolescent, Adult, Animals, Child, Disease Models, Animal, Ear, Inner, Female, Genes, Dominant, Genes, Recessive, Hearing Loss, Hearing Loss, Sensorineural, Homozygote, Humans, LIM-Homeodomain Proteins, Male, Mice, Mutation, Missense, Pedigree, Transcription Factors, Whole Exome Sequencing}, issn = {1432-1203}, doi = {10.1007/s00439-018-1899-7}, author = {Schrauwen, Isabelle and Chakchouk, Imen and Liaqat, Khurram and Jan, Abid and Nasir, Abdul and Hussain, Shabir and Nickerson, Deborah A and Bamshad, Michael J and Ullah, Asmat and Ahmad, Wasim and Leal, Suzanne M} } @article {62, title = {A Syndromic Intellectual Disability Disorder Caused by Variants in TELO2, a Gene Encoding a Component of the TTT Complex.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 05 05}, pages = {909-918}, abstract = {

The proteins encoded by TELO2, TTI1, and TTI2 interact to form the TTT complex, a co-chaperone for maturation of the phosphatidylinositol 3-kinase-related protein kinases (PIKKs). Here we report six affected individuals from four families with intellectual disability (ID) and neurological and other congenital abnormalities associated with compound heterozygous variants in TELO2. Although their fibroblasts showed reduced steady-state levels of TELO2 and the other components of the TTT complex, PIKK functions were normal in cellular assays. Our results suggest that these TELO2 missense variants result in loss of function, perturb TTT complex stability, and cause an autosomal-recessive syndromic form of ID.

}, keywords = {Adolescent, Carrier Proteins, Child, Female, Humans, Intellectual Disability, Male, Molecular Chaperones, Pedigree, Phosphatidylinositol 3-Kinases, Protein-Serine-Threonine Kinases, Telomere-Binding Proteins}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.03.014}, author = {You, Jing and Sobreira, Nara L and Gable, Dustin L and Jurgens, Julie and Grange, Dorothy K and Belnap, Newell and Siniard, Ashley and Szelinger, Szabolcs and Schrauwen, Isabelle and Richholt, Ryan F and Vallee, Stephanie E and Dinulos, Mary Beth P and Valle, David and Armanios, Mary and Hoover-Fong, Julie} }