title: Whole exome sequencing in dominant cataract identifies a new causative factor, CRYBA2, and a variety of novel alleles in known genes.
abstract: Pediatric cataracts are observed in 1-15 per 10,000 births with 10-25 % of cases attributed to genetic causes; autosomal dominant inheritance is the most commonly observed pattern. Since the specific cataract phenotype is not sufficient to predict which gene is mutated, whole exome sequencing (WES) was utilized to concurrently screen all known cataract genes and to examine novel candidate factors for a disease-causing mutation in probands from 23 pedigrees affected with familial dominant cataract. Review of WES data for 36 known cataract genes identified causative mutations in nine pedigrees (39 %) in CRYAA, CRYBB1, CRYBB3, CRYGC (2), CRYGD, GJA8 (2), and MIP and an additional likely causative mutation in EYA1; the CRYBB3 mutation represents the first dominant allele in this gene and demonstrates incomplete penetrance. Examination of crystallin genes not yet linked to human disease identified a novel cataract gene, CRYBA2, a member of the βγ-crystallin superfamily. The p.(Val50Met) mutation in CRYBA2 cosegregated with disease phenotype in a four-generation pedigree with autosomal dominant congenital cataracts with incomplete penetrance. Expression studies detected cryba2 transcripts during early lens development in zebrafish, supporting its role in congenital disease. Our data highlight the extreme genetic heterogeneity of dominant cataract as the eleven causative/likely causative mutations affected nine different genes, and the majority of mutant alleles were novel. Furthermore, these data suggest that less than half of dominant cataract can be explained by mutations in currently known genes.
authors.affiliation: Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Reis
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Tyler
authors.forename: Sanaa
authors.initials: S
authors.lastname: Muheisen
authors.forename: Victor
authors.initials: V
authors.lastname: Raggio
authors.forename: Leonardo
authors.initials: L
authors.lastname: Salviati
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Han
authors.forename: Deborah
authors.initials: D
authors.lastname: Costakos
authors.forename: Hagith
authors.initials: H
authors.lastname: Yonath
authors.forename: Sarah
authors.initials: S
authors.lastname: Hall
authors.forename: Patricia
authors.initials: P
authors.lastname: Power
authors.forename: Elena V
authors.initials: EV
authors.lastname: Semina
mesh_terms: D000328:Adult; D000483:Alleles; D019943:Amino Acid Substitution; D000818:Animals; D002386:Cataract / Q000235:genetics* / Q000378:metabolism; D002675:Child, Preschool; D004252:DNA Mutational Analysis / Q000379:methods; D059472:Exome; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D005799:Genes, Dominant; D030342:Genetic Diseases, Inborn / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007223:Infant; D008297:Male; D020125:Mutation, Missense; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins / Q000096:biosynthesis / Q000235:genetics; D038205:beta-Crystallin A Chain / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D029961:Zebrafish Proteins; D038205:beta-Crystallin A Chain