Frequencies of mutations in the connexin 26 gene [GJB2] in two populations of Iran [Tehran and Tabriz]

While hearing loss has been considered to be a very heterogeneous disorder, mutations in Gap junction beta 2 [GJB2] gene encoding Connexin 26 [Cx26] protein are the major cause of autosomal recessive and sporadic non-syndromic deafness in many populations. In this study, we have investigated the prevalence of the GJB2 gene mutations using nested PCR pre screening strategy and direct sequencing method. Two hundred and seventy two hearing impaired subjects were studied from 210 families obtained from two large cities of Iran [Tehran and Tabriz]. Twenty four different genetic variants were identified. Cx26 mutations were found in 53 of the 210 families [25.2%] including T8M, 35delG, W24X, R32H, V37I, E47X, 167delT, delE120, Y136X, R143W, R184P, 235delC and V27I+E114G. Homozygosity and compound heterozygosity for the Cx26 mutations were found in 39 of 210 [18.5%] families. Homozygosity for the 35delG mutation was the most common that causes hearing loss in 28 [13.3%] patients. Six novel variants H16R, E101E, K102Q, G200R, 327delG and G130A were detected in this study. As a conclusion, the present survey revealed that the rate of mutation in Cx26 gene in our area is lower than in Europe; nevertheless, this rate is regarded as a considerable cause of deafness in the cited provinces in Iran

Two novel mutations and predominant 35delG mutation in the connexin 26 gene [GJB2] in Iranian populations

Mutations in the GJB2 gene encoding Connexin 26 [Cx26] protein are a major cause for autosomal recessive non syndromic and sporadic deafness in many populations. In this study we have investigated the prevalence of the GJB2 gene mutations using nested PCR pre screening strategy and direct sequencing method. Two hundred and sixty autosomal recessive non syndromic and sporadic deaf subjects from 199 families in two provinces of Iran [Gilan and Khorasan] were studied. Altogether 14 different genetic variants were identified from which 2 were novel variant [327delG+G109G and 431insC]. Eight GJB2 mutations including 35delG, 235delC, W77X, R127H, M34T, V27I+E114G, L90P and delE120 were also found in 54 of 199 families [27%]. Four polymorphysms V27I, S86T, V153I and G160S also were detected. Thirty two of 199 families were observed to have GJB2 mutations in both alleles [16%]. The most common mutation was 35delG so that 43 out of 55 GJB2 mutations [78.2%] contained 35delG mutation

Aging coefficient in different provinces of Iran

Aging coefficient [AC] or aged-child ratio or age composition; takes into account the numbers and areas at both ends of the age distribution simultaneously. AC is the total number of individuals aged 65 years and more, divided by the total number of individuals aged 14 years, multiplied by 100. Herein, age composition in Iranian popu1ations, according to different provinces, place of residence [urban and rural] and sex was investigated. General AC in Iran was found to be 7.64%. The lowest A.C. was in Kohkiloye-BoyerAhmad 3.83%], and the highest A.C. in Semnan province [12.25%]. On the whole, the ACs of men [urban and rural] was more than that of the urbanites