title: Spectrum of genetic changes in patients with non-syndromic hearing impairment and extremely high carrier frequency of 35delG GJB2 mutation in Belarus.
abstract: The genetic nature of sensorineural hearing loss (SNHL) has so far been studied for many ethnic groups in various parts of the world. The single-nucleotide guanine deletion (35delG) of the GJB2 gene coding for connexin 26 was shown to be the main genetic cause of autosomal recessive deafness among Europeans. Here we present the results of the first study of GJB2 and three mitochondrial mutations among two groups of Belarusian inhabitants: native people with normal hearing (757 persons) and 391 young patients with non-syndromic SNHL. We have found an extremely high carrier frequency of 35delG GJB2 mutation in Belarus -5.7%. This point deletion has also been detected in 53% of the patients with SNHL. The 312del14 GJB2 was the second most common mutation in the Belarus patient cohort. Mitochondrial A1555G mt-RNR1 substitution was found in two SNHL patients (0.55%) but none were found in the population cohort. No individuals carried the A7445G mutation of mitochondrial mt-TS1. G7444A as well as T961G substitutions were detected in mitochondrial mt-RNR1 at a rate of about 1% both in the patient and population cohorts. A possible reason for Belarusians having the highest mutation carrier frequency in Europe 35delG is discussed.
authors.affiliation: Institute of Genetics and Cytology, National Academy of Sciences, Minsk, Belarus. n.danilenko@tut.by
authors.forename: Nina
authors.initials: N
authors.lastname: Danilenko
authors.forename: Elena
authors.initials: E
authors.lastname: Merkulava
authors.forename: Marina
authors.initials: M
authors.lastname: Siniauskaya
authors.forename: Olga
authors.initials: O
authors.lastname: Olejnik
authors.forename: Anastasia
authors.initials: A
authors.lastname: Levaya-Smaliak
authors.forename: Alena
authors.initials: A
authors.lastname: Kushniarevich
authors.forename: Andrey
authors.initials: A
authors.lastname: Shymkevich
authors.forename: Oleg
authors.initials: O
authors.lastname: Davydenko
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D005838:Genotype; D034381:Hearing Loss / Q000235:genetics*; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D002094:Republic of Belarus; D055815:Young Adult
chemical_list: D017630:Connexins; D004272:DNA, Mitochondrial; C000607042:GJB2 protein, human; D000072259:Connexin 26