Interesting, that almost all examined patients (except one Yakut patient) in this study were homozygous for the allele T of intronic rs7994748 (GJB2) that is consistent with the studies by Grillo et al. (2015) and by Parzefall et al. (2017) in which the association of this rs7994748 allele with hearing loss was presumed [71,72]. This evidence concerns the gene GJB2 and hearing loss disorder.