Deafness, Autosomal Recessive 23

A number sign (#) is used with this entry because autosomal recessive deafness-23 (DFNB23) is caused by homozygous mutation in the gene encoding protocadherin-15 (PCDH15; 605514) on chromosome 10q21.

Mutation in the PCDH15 gene can also cause Usher syndrome type IF (602083).

Clinical Features

Ahmed et al. (2003) reported 3 families with isolated deafness. Two of the families had no history of nyctalopia, and the funduscopy and electroretinograms were normal in 2 older affected individuals from each family (age range, 13-44 years). Vestibular responses were intact in affected individuals.

Doucette et al. (2009) reported a consanguineous family from Newfoundland, Canada, with isolated hearing loss that was neurosensory, prelingual, and severe to profound. Ancestors of the family had emigrated from England in the early 1800s to settle a fishing 'outport' on Newfoundland's southern coast. Detailed examination of 2 homozygous carriers in middle age showed no evidence of Usher syndrome and no vestibular abnormalities.

Molecular Genetics

In affected members of 2 unrelated families with isolated deafness, Ahmed et al. (2003) identified 2 different homozygous mutations in the PCDH15 gene (605514.0006 and 605514.0007, respectively).

In affected members of a consanguineous family from Newfoundland with isolated deafness, Doucette et al. (2009) identified a homozygous mutation in the PCDH15 gene (V528D; 605514.0010).