Linkage of congenital, recessive deafness (DFNB4) to chromosome 7q31 and evidence for genetic heterogeneity in the Middle Eastern Druze population

Clinically significant hearing loss affects 1 in 1000 infants and it is estimated that at least 50% of these cases are due to a genetic cause. Some forms of inherited deafness are syndromic and affected individuals have a specific pattern of additional features while in other families the deafness is non-syndromic and there is no other recognizable phenotype. Analysis of several large families with syndromic and non-syndromic forms of deafness have been used in genetic linkage analysis to identify genes or gene locations that cause deafness. Here, we describe a large Middle-Eastern Druze family with recessive non-syndromic deafness and demonstrate linkage between deafness in this family and human chromosome 7q31 with a lod score exceeding 5. 5. This is the first evidence for a gene at this location that causes deafness. In addition, we found that deafness in three other Druze pedigrees, one related to the linked family, is not linked to this chromosomal location. This suggests that there are multiple nonallelic mutations for deafness in this genetic isolate.