Genetic linkage analysis of DFNB7/11 locus in patients with autosomal recessive non syndromic hearing loss from Hamedan province

Hearing loss is a most common sensory deficit in humans. The hearing loss may be conductive, sensorineural, or mixed (syndromic or nonsyndromic), prelingual or postlingual. Due to the complexity of the hearing mechanism, it is not surprising that several hundred genes might be involved in causing hereditary hearing loss. So far 152 loci have been identified which are associated with the most common type of hearing loss. This study aimed to analyze genetic linkage of DFNB7/11 locus in families with autosomal recessive nonsyndromic hearing loss from Hamedan province.
In this descriptive laboratory study, 24 families from Hamedan province with autosomal recessive nonsyndromic hearing loss were examined. Selected families in this study had consanguinity and they were negative for GJB2 gene mutations. Linkage analysis was performed by 7 markers (STR) for DFNB7/11 locus.
After examining different families, one family of the 24 families (4.16%) showed linkage to the DFNB7/11 locus, but in examining different exons and promoter of TMC1 gene, no mutation was found. Lack of TMC1gene mutations in mentioned familyy suggests mutations exist in noncoding regions of TMC1 genes or new gene exists in this locus. SLINK value and LOD score of this family was 1.45 and 0.54 respectively.
Based on the results of this study, DFNB7/11 locus may not have important role in causing hearing loss of population studied, but further studies are necessary to determine more precisely the role of this locus in hearing loss in Iranian population.