Objective: The goal of this study was to characterize the disease-causing mutations in a Chinese family with congenital nuclear and posterior polar cataracts.
Methods: Clinical data of patients in the family were recorded using slit-lamp photography and high definition video. Genomic DNA samples were extracted from the peripheral blood of the pedigree members and 100 healthy controls. Mutation screening was performed in the candidate genes by bi-directional sequencing of the amplified products.
Results: The congenital cataract phenotype of the pedigree was identified by slit-lamp examinations and observation during surgery as nuclear and posterior polar cataracts. Through the sequencing of the candidate genes, a heterozygous c. 418C>T change was detected in the coding region of the γD-crystallin gene (CRYGD). As a result of this change, a highly conserved arginine residue was replaced by a stop codon (p. R140X). This change was discovered among all of the affected individuals with cataracts, but not among the unaffected family members or the 100 ethnically matched controls.
Conclusions: This study identified a novel congenital nuclear and posterior polar cataract phenotype caused by the recurrent mutation p. R140X in CRYGD.
Keywords: Greek key motif; congenital cataract; mutation; stop codon; γD-crystallin.