In a large kindred of German descent, we found a novel allele that segregates with deafness when present in trans with the 35delG allele of GJB2. Qualitative polymerase chain reaction-based allele-specific expression assays showed that expression of both GJB2 and GJB6 from the novel allele is dramatically reduced. This is the first evidence of a deafness-associated regulatory mutation of GJB2 and of potential coregulation of GJB2 and GJB6.