A nonsense mutation of CRYGC associated with autosomal dominant congenital nuclear cataracts and microcornea in a Chinese pedigree

PURPOSE To report the identification of a nonsense mutation in γC-crystallin (CRYGC) associated with autosomal dominant congenital nuclear cataracts and microcornea in a Chinese family. METHODS We investigated four generations of a Chinese family six of whose members were affected by nuclear cataracts and microcornea. The genomic DNA was extracted from peripheral blood leukocytes. All reported nuclear cataract-related candidate genes were screened for causative mutations by direct DNA sequencing. The effects of amino acid changes on the structure and function of proteins were predicted by bioinformatics analysis. RESULTS All affected individuals in this family exhibited nuclear cataracts and microcornea. Direct sequencing of the candidate gene cluster showed a c.471G>A transition in exon 3 of CRYGC, which co-segregated according to family members with cataracts, and was not observed in 100 normal controls. This single nucleotide change was predicted to introduce a translation stop codon at tryptophan 157 (W157X). Bioinformatics analysis showed that the mutation was predicted to affect the function and secondary structure of the CRYGC protein. CONCLUSIONS This study identified a disease-causing mutation c.471G>A in CRYGC in a Chinese family with cataracts, expanding the mutation spectrum of CRYGC causing congenital cataracts.