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.
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 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.
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).
The DFNA2 locus for autosomal dominant nonsyndromic hearing impairment on chromosome 1p34 contains at least 2 genes responsible for hearing loss, GJB3 and KCNQ4.
Recessive mutations of MYO15A are associated with profound, nonsyndromic hearing loss DFNB3 in humans, and deafness and circling behavior in shaker 2 mice.
We estimate the prevalence of homozygous MYO15A mutations in autosomal recessive nonsyndromic deafness in Turkey as 0.062 (95% confidence interval is 0.020-0.105).
Mutation in PCDH15 may modify the phenotypic expression of the 7511T>C mutation in MT-TS1 in a Chinese Han family with maternally inherited nonsyndromic hearing loss.
This study validates the DFNB23 designation and supports the hypothesis that missense mutations in conserved motifs of PCDH15 cause nonsyndromic hearing loss.