Mutation of the gap junction protein alpha 8 (GJA8) gene causes autosomal recessive cataract

Background: GJA8 encodes connexin-50, a gap junction protein in the eye lens. Mutations in GJA8 have been reported in families with autosomal dominant cataract. Objective: To identify the disease gene in a family with congenital cataract of autosomal recessive inheritance. Methods: Eight candidate genes were screened for pathogenic alterations in affected and unaffected family members and in normal unrelated controls. Results: A single base insertion leading to frameshift at codon 203 of connexin 50 was found to co-segregate with disease in the family. Conclusions: These results confirm involvement of GJA8 in autosomal recessive cataract.