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

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