Mutations in the KCNQ4 K+ channel gene, responsible for autosomal dominanthearing loss, cluster in the channel pore region

The DFNA2 locus for autosomal dominant nonsyndromic hearing impairment on c hromosome 1p34 contains at least 2 genes responsible for hearing loss, GJB3 and KCNQ4, GJB3 is a member of the connexin gene family and KCNQ4 is a vol tage-gated potassium channel, KCNQ4 mutations were first found in a French family, and later also in a Belgian, an American and two Dutch families. He re we present the analysis of the GJB3 and KCNQ4 genes in a third Dutch fam ily linked to DFNA2, No mutation was found in GJB3, but a missense mutation changing a conserved Leu residue into His (L274H) was found in the coding region of the KCNQ4 gene in all patients of this DFNA2 family, Examination of the position of all known KCNQ4 mutations showed a clustering of mutatio ns in the pore region of the KCNQ4 gene, responsible for the ion selectivit y of the channel. The clustering of mutations in this domain confirms its i mportance. Am. J, Med, Genet, 93:184-187, 2000, (C) 2000 Wiley-Liss, Inc.