Deafness, Autosomal Recessive 112

A number sign (#) is used with this entry because of evidence that autosomal recessive deafness-112 (DFNB112) is caused by homozygous mutation in the BDP1 gene (607012) on chromosome 5q13. One such family has been reported.

Description

DFNB112 is characterized by postlingual progressive sensorineural hearing impairment (Girotto et al., 2013).

Clinical Features

Girotto et al. (2013) reported a consanguineous Qatari family in which 4 sibs had bilateral postlingual early-onset progressive sensorineural hearing impairment. Hearing loss, which was first noted at age 2 to 4 years, initially involved mild loss of medium and high frequencies, but gradually progressed to include low frequencies, with moderate to severe loss of medium and high frequencies. The affected individuals showed no apparent syndromic features.

Mapping

In a consanguineous Qatari family with postlingual progressive sensorineural hearing loss, negative for mutation in the most common worldwide nonsyndromic hearing loss-associated genes, Girotto et al. (2013) performed linkage analysis and obtained the maximum achievable lod score of 3.8 at a 40-Mb region on chromosome 5q13. There were 2 peaks, the first ranging from rs853803 to rs623297 (chr5:67,761,853-72,408,339) and the second ranging from rs12153302 to rs17371964 (chr5:73,777,378-107,296,793).

Molecular Genetics

In a consanguineous Qatari family with postlingual progressive sensorineural hearing loss mapping to chromosome 5q13, Girotto et al. (2013) performed exome analysis of the targeted region and identified homozygosity for a nonstop mutation in the BDP1 gene (X2625E; 607012.0001) that segregated with disease and was not found in controls. The authors noted that the BDP1 gene maps in the DFNB49 (610153) locus, but stated that no predicted pathogenic mutations were detected in the MARVELD2 gene (610572) in this family.