Genetic linkage Analysis of DFNB1)GJB6 (and DFNB4 (SLC26A4) loci with Autosomal Recessive Non-Syndromic Hearing Loss (ARNSHL) in Kermanshah, a western province of Iran

Hearing Loss (HL) is the most common sensory disorder in human with an incidence of about one in 650 alive neonates. It is estimated that at least 50% of pre-lingual HL has a genetic basis. Almost 70% of genetic HL are non-syndromic (NSHL) and of NSHL cases, the autosomal recessive form (ARNSHL) comprises about 80%. Iranian population especially the Kurdish ethnicity with high consanguinity rate offers suitable opportunity for the study of ARNSHL. The aim of this study was to clarify the role of DFNB1 (GJB6) and DFNB4 (SLC26A4) loci in ARNSHL in Kermanshah, Iran.
DFNB1 (GJB6) and DFNB4 (SLC26A4) loci were analysed in a cohort study on 28 ARNSHL families (GJB2- negative) from Kermanshah province in Iran. Genetic linkage analysis was applied on 140 samples from 140 individuals by polymerase chain reaction – polyacrylamide gel electrophoresis (PCR-PAGE) technique. Silver staining was used for visualizing the bands. At least, two informative screening markers were analyzed for each locus. Haplotypes were analyzed to determine linkage.
None of the families studied showed linkage to DFNB1 and DFNB4 loci.
Our experiment, similar to previous studies, imply the absence of GJB6 mutations in Iran. None of the families showed linkage to DFNB4 locus. As it normally ranks second after DFNB1 in Iran and other parts of the world, more studies are warranted on more families to elucidate the role of this locus as well as other loci in etiogy of ARNSHL.