The textbook was prepared in accordance with the requirements of the Federal State Educational Standard of Higher Education in the direction of training (specialty) 31.05.01 General Medicine (specialist level) for studying the discipline «Medical Genetics». For students studying in the specialties: «General Medicine», 2023, PC-5, PC-6, PC-8, PC-9. The textbook presents current data on monogenic diseases, which are divided into 16 separate groups. Each group of diseases is described in detail with illustrations, tables and formulas for a better understanding of the material. The publication includes test tasks and situational tasks with examples of answers.