Cochleosaccular dysplasia associated with a connexin 26 mutation in keratitis-ichthyosis-deafness syndrome

OBJECTIVE: The objective of this study was to characterize the temporal bone phenotype associated with a mutation of GJB2 (encoding connexin 26). STUDY DESIGN: The authors conducted correlative clinical, molecular genetic, and postmortem histopathologic analysis. METHODS: The study subject was a male infant with keratitis-ichthyosis-deafness (KID) syndrome. We performed a nucleotide sequence analysis of GJB2 and a histopathologic analysis of the temporal bones. RESULTS: The subject was heterozygous for G45E, a previously reported KID syndrome mutation of GJB2. The primary inner ear abnormality was dysplasia of the cochlear and saccular neuroepithelium. CONCLUSIONS: GJB2 mutations can cause deafness in KID syndrome, and possibly in other GJB2 mutant phenotypes, by disrupting cochlear differentiation.