the incidence of pre-lingual hearing loss (hl) is about 1 in 1000 neonates. more than 60% of cases are inherited. non-syndromic hl (nshl) is extremely heterogeneous: more than 130 loci have been identified so far. the most common form of nshl is the autosomal recessive form (arnshl). in this study, a cohort of 36 big arnshl pedigrees with 4 or more patients from 7 provinces of iran was investig...