Mutations in potassium voltage-gated channel subfamily Q member 4 (KCNQ4) are etiologically linked to nonsyndromic hearing loss (NSHL), deafness nonsyndromic autosomal dominant 2 (DFNA2).
Once the <i>KCNQ4</i> pathogenic variant has been identified in a family member, prenatal testing for a pregnancy at increased risk and preimplantation genetic diagnosis for DFNA2nonsyndromic hearing loss are possible.
Mutations in the SLC26A4 gene have been shown to cause a type of deafness referred to as large vestibular aqueduct syndrome (LVAS), whereas mutations in the GJB3 gene have been associated with nonsyndromic deafness.
In a recent study, we have identified a missense mutation, p.V174M, in the connexin 31 encoded by the GJB3 gene, in a patient with nonsyndromic hearing loss.
Mutations of GJB2 and SLC26A4 are two major genetic causes, whereas mutations of GJB3 and 12s rRNA result in the development of hearing loss in a small percentage of sporadic nonsyndromic hearing loss cases.
Our results suggest the variants of GJC3, GJB4, and GJB3 may be the common genetic risk factor, after variants of GJB2, for the development of nonsyndromic HL in Taiwan.
The DFNA2 locus for autosomal dominant nonsyndromic hearing impairment on chromosome 1p34 contains at least 2 genes responsible for hearing loss, GJB3 and KCNQ4.