Anastasiya M Levaya-Smaliak, Elena P Merkulava, Nina G Danilenko, Marina Siniauskaja, Ol'ga Olejnik
JHS 2011; 1(2): EA57-59
Background: About 100 genes are determined to be involved in hearing loss in humans. Among them the major one is GJB2 coding connexin 26. The deletion of any one of six G nucleotides at positions 30-35, so called 35delG mutation, is most often found in GJB2 gene in Europeans. The aim of the study was: 1) to analyze 35delG mutation`s rate in the large group of children with moderate-to-profound sensorineural hearing loss (SNHL); 2) to determine the influence of risk factors of non–syndromic SNHL .
Materials and methods: 392 children (aged 3-17) with SNHL from moderate-to-profound were examined. A screening for 35delG, pure – tone audiometry and family interviews were performed. A comparative analysis of gender characteristics, degree of hearing loss and risk factors in three groups of children: 35delG heterozygous, 35delG homozygous and without this mutation were performed. The influence of risk factors of SNHL is statistically estimated by using R-System.
Results: Among children with moderate and profound SNHL 45% are homozygous and 15% are heterozygous for 35delG GJB2. The most significant risk factors leading to deafness in group of patients without mutation are perinatal risk factors.
Conclusions: Our study reveals that single-nucleotide deletion 35delG in GJB2 is the main genetic cause of SNHL in Belarus as it is detected in homo- or heterozygous state in 60% of the patients with SNHL. A molecular analysis for 35delG mutation should be performed in cases of positive family story, severe – profound congenital hearing loss, presence of perinatal risk factors.
Key words: Connexin 26, GJB2 gene, 35delG mutation, non-syndromic hearing loss
Keywords: 35delG, GJB2, Connexin 26, non-syndromic hearing loss