GJB2 and autosomal dominant nonsyndromic hearing loss 3A: The majority of GJB2 mutations are recessively inherited and, being in homozygous or compound heterozygous states, result in nonsyndromic recessive deafness (DFNB1) while some of GJB2 mutations are dominantly inherited and lead to nonsyndromic autosomal dominant deafness (DFNA3) or several different syndromes associating hearing loss with skin disorders [2,4,20,21,22,23,24,25].