GJB۲ gene related nonsyndromic hearing loss in Mazandaran Province, north of Iran

Backgrounds: Congenital hearing loss is the most common sensory deficit in the world andmutations in the GJB۲ gene are the most common cause of deafness in many populations. Thefrequency of GJB۲ mutations is estimated at ۱۶% in Iran and varies among different provinceswith a decreasing trend from north to south. The aim of this study was to investigate thefrequency of GJB۲ mutations in Mazandaran province, north of Iran, among non-syndromichearing loss patients.Materials and Methods: ۲۶۲ patients from ۲۰۴ families participated in this study. Aftergenomic DNA extraction, GJB۲ gene analysis was carried out using DNA sequencing of bothcoding and non-coding regions by the ABI ۳۱۳۰XL genetic analyzer.Results: ۳۰.۱۵% of all subjects showed mutations in the GJB۲ gene. Four mutations, includingc.۳۵delG (Gly۱۲Valfs*), IVSI-۱+۱G>A, c.۹۵G>A (Arg۳۲His), and c.۲۲۴ G>A (Arg۷۵Gln)comprises ۶۹.۸۹% of all mutations in this study. ۳۵delG and IVSI-۱ were the most commonmutations among patients respectively. Codon ۷۵ mutation (c.۲۲۴G>A, p: Arg۷۵Gln) withautosomal dominant inheritance was seen in ۷ cases from ۳ families. ۲۲ patients showed onlyone mutation in the GJB۲ gene and in ۱۲۶ (۴۸.۰۹%) individuals, parents had a consanguineousmarriage.Conclusion: The frequency of GJB۲ gene-related hearing loss among patients was higher thanaverage (۱۶%) in this province. This study also showed the dominant inheritance of the GJB۲gene in this area. Consanguineous marriage also showed highly frequent among parents. Moreinvestigation is needed to clarify for those ۲۲ patients with one mutation in the GJB۲ gene; eithertwo gene inheritance or another gene may be responsible for hearing loss.

کلیدواژه ها:

Hearing Loss ، GJB۲ ، Mazandaran ، Hereditary Deafness ، Nonsyndromic