Connexin 26 gene: defining the role of the V1531 mutation

Mutations in the GJB2 gene, which encodes the gap junction protein Connexin 26 (Cx26), are the major cause of genetic non-syndromic hearing loss. The role of several GJB2 mutations in causing hereditary deafness remains controversial. By combining genetic, clinical and biochemical studies, we have analysed the possible pathogenetic role of the V153I mutation. Molecular epidemiological studies revealed a V153I allele frequency in the normal hearing population of 0.49. The same allele has been detected at the homozygous state in a normal hearing subject. Finally, functional data obtained in transiently transfected HeLa cells showed that V153I was correctly synthesized and targeted to the plasma membrane and the formed intercellular channels function was not disturbed, as the intercellular diffusion of Lucifer Yellow remained unchanged. These findings provide new insights against a possible pathogenetic role of the V153I mutation of the GJB2 gene, and indicate it as a possible neutral variant. Furthermore, these data can also help physicians to provide better genetic counselling to at-risk couples.