DFNB48, a new nonsyndromic recessive deafness locus, maps to chromosome 15q23-q25.1

Nonsyndromic deafness locus (DFNB48) segregating as an autosomal recessive trait has been mapped to the long arm of chromosome 15 in bands q23-q25.1 in five large Pakistani families. The deafness phenotype in one of these five families (PKDF245) is linked to D15S1005 with a lod score of 8.6 at θ = 0, and there is a critical linkage interval of approximately 7 cM on the Marshfield human genetic map, bounded by microsatellite markers D15S216 (70.73 cM) and D15S1041 (77.69 cM). MYO9A, NR2E3, BBS4, and TMC3 are among the candidate genes in the DFNB48 region. The identification of another novel nonsyndromic recessive deafness locus demonstrates the high degree of locus heterogeneity for hearing impairment, particularly in the Pakistani population. Loci have been mapped either in endogamous population or in families with children of consanguineous marriages (Friedman and Griffith 2003). As a consequence of the unique socio-cultural practices in the population of Pakistan, aproximately 60% of marriages are consanquineous, of wich more than 80% are between first counsin (Hussain and Bittles 1998). These large consanguineous families are a powerful resource for genetic linkage studies of recessively inherited dis-order. In this communication, we report a novel deafness locus DFNB48 genetically mapped with the aid of five consanguineous families from remote areas of Sindh Province in Pakistan. This locus resides in an interval of approximately 7 cM on chromosome 15q23-q25.1.