[New recurrent extended deletion, including GJB2 and GJB6 genes, results in isolated sensorineural hearing impairment with autosomal recessive type of inheritance].

Hereditary hearing loss with the autosomal recessive type of inheritance of the DFNB 1 genetic type, caused by mutations in the GJB2 gene, is the main reason of innate non-syndromal hearing impairment in most developed countries of the world (including Russia). Intragenic point mutations prevail among the GJB2 gene defectors; however, extended deletions in the DFNB1 locus are also found with considerable frequency in some populations (for example, Spain, Great Britain, France, United States, and Brazil). Among the four known extended deletions, only one deletion affects directly the GJB2 gene sequence and was described in a single family. A new extended deletion in the GJB2 and GJB6 gene sequences (approximately 101 kb in size; NC_000013.10:g.20,757,021_20,858,394del), detected in three unrelated Russian patients, was described and characterized. Ingush origin of this mutation is assumed. If the new deletion is frequent, its detection is very important for the genetic consulting of families with hereditary hearing impairment.