Novel mutations in GJB2 encoding connexin-26 in Japanese patients with keratitis-ichthyosis-deafness syndrome

Background: Germline missense mutations in the GJB2 gene that encodes connexin-26 (Cx26) have recently been found to be the cause of the keratitis-ichthyosis-deafness (KID) syndrome. Objectives: To define the GJB2 mutations in three Japanese patients with KID syndrome. Methods: Genomic DNA was extracted from peripheral blood and used to amplify the GJB2 gene. Direct sequencing and endonuclease digestion were used for mutation analysis and DNA-based diagnosis. Results: We identified two heterozygous mis-sense mutations (D50Y, D50N) in the GJB2 gene in three Japanese patients with KID syndrome. All mutations were located on the first extracellular domain of Cx26. Conclusions: These data expand the GJB2 mutation database and show that a dominant mutation of Cx26 can cause KID syndrome in Japanese patients.