Background. Atrial fibrillation (AF) is the most common type of heart rhythm disturbance, leading to the development of lifethreatening conditions, such as cardio embolism, heart failure, and even sudden cardiac death. In recent years, the genetic aspects of AF have been actively discussed. The largest number of genetic predictors of AF was identified after a full genome-wide association studies (GWAS). Given that so far no studies of the association of rs10824026 polymorphism of chromosome 10q22 with the development of AF have been conducted in the Russian population, we conducted this clinical study. Aim. Checking the associations of the development of AF with the single-nucleotide polymorphism rs10824026 of the SYNPO2L gene in the East-Siberian population. Materials and methods. The study design was formed in accordance with the National Standard of the Russian Federation Good Clinical Practice, GOST P 52379-2005. The study uses design - “case-control”. The main group of patients - patients with known cardiac arrhythmias by the type of AF (n=106, average age 57.0±9 years, men 49.4%, women 50.6%), the group was formed using the criteria of the World Health Organization and the European Society of cardiologists. The control group (n=105, average age 57.0±9 years, men - 50.0%, women - 50.0%) was selected by age and gender from the DNA bank of international studies MONICA (Multinational MONItoring of trends and determinants in cardiovascular disease) under a joint agreement with the Research Institute of Therapy and preventive medicine - Novosibirsk. DNA was isolated by phenol-chloroform extraction. Among other things, among the research methods, routine laboratory methods were used; instrumental data; and invasive tactics such as CAG. Results. As a result of clinical genetic testing, it was found that the frequency of G/G polymorphism of the SYNPO2L gene in patients with AF shows a statistically significant difference.