Author contribution: Novikova EI — collection of clinical material, conducting molecular genetic studies, analysis and statistical processing of the results, preparation and writing of the article; Kudinova EA — analysis of literature, analysis of the research results; Bozhenko VK — analysis of the results, article text editing; Solodkiy VA — planning and analysis of the research results, article test editing.

Compliance with ethical standards: the study was approved by the ethics committee of the RSCR (minutes #3 of March 27, 2020); all patients included in the study signed a voluntary informed consent.