Data of own researches and the review of the literary data for studying pathogenesis and features of HMSN, type 1 Х caused by mutations in gene GJB1 are presented in this paper. X-linked HMSN is the genetic variant second for frequency in Russian, it constitute 22% from total of patients of this group. Features of this genetic variant are considerable distinction in weight clinical displays at patients man's and female. It is shown that at the majority of female patients clinical displays are expressed less, and at 20% were absent at all. The assumption is come out that at indicators of CNV from 35 to 52 m/s, it is necessary to conduct research in gene GJB1 especially at patients of a female and as to carry out search of mutations at all relatives with HMSN, type 1 X even in the absence of complaints from their party.