Exome sequencing identifies novel and recurrent mutations in GJA8 and CRYGD associated with inherited cataract.
BACKGROUND
Inherited cataract is a clinically important and genetically heterogeneous cause of visual impairment. Typically, it presents at an early age with or without other ocular/systemic signs and lacks clear phenotype-genotype correlation rendering both clinical classification and molecular diagnosis challenging. Here we have utilized trio-based whole exome sequencing to discover mutations in candidate genes underlying autosomal dominant cataract segregating in three nuclear families.


RESULTS
In family A, we identified a recurrent heterozygous mutation in exon-2 of the gene encoding γD-crystallin (CRYGD; c.70C > A, p.Pro24Thr) that co-segregated with 'coralliform' lens opacities. Families B and C were found to harbor different novel variants in exon-2 of the gene coding for gap-junction protein α8 (GJA8; c.20T > C, p.Leu7Pro and c.293A > C, p.His98Pro). Each novel variant co-segregated with disease and was predicted in silico to have damaging effects on protein function.


CONCLUSIONS
Exome sequencing facilitates concurrent mutation-profiling of the burgeoning list of candidate genes for inherited cataract, and the results can provide enhanced clinical diagnosis and genetic counseling for affected families.
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA. mackayd@vision.wustl.edu.
Donna S
DS
Mackay
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA. bennett@vision.wustl.edu.
Thomas M
TM
Bennett
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA. culican@vision.wustl.edu.
Susan M
SM
Culican
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA. shiels@vision.wustl.edu.
Alan
A
Shiels
D002386:Cataract / Q000235:genetics* / Q000473:pathology; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D059472:Exome; D005260:Female; D020869:Gene Expression Profiling; D056726:Genetic Association Studies; D006579:Heterozygote; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D038222:gamma-Crystallins / Q000235:genetics* / Q000378:metabolism; D000099264:Connexin 50
D017630:Connexins; D038222:gamma-Crystallins; D000099264:Connexin 50; C504903:CRYGD protein, human