Objective. To analyze the polymorphism in exon 4 of the gamma-synuclein gene (SNCG) in patients with autoantibodies against the gamma-synuclein protein. Material and methods. To identify autoantibodies against gamma-synuclein, the serum from patients with chronic cerebral ischemia and cervical osteochondrosis was used. All patients were women of the Slavic ethnic group, mean age 61±5 years. The isolated genomic DNA was used to determine the point mutation in exon 4 by the restriction endonuclease HphI and subsequent sequencing of the resulting fragments to confirm the results. Results and conclusion. Antibodies against gamma-synuclein were identified in 2 patients with chronic cerebral ischemia and 3 with cervical osteochondrosis. All five patients had a T to A substitution at position 371, which was detected by the restriction endonuclease HphI resulting in a hydrolysis of the amplicon and the formation of two fragments. The subsequent sequencing of exon 4 of the SNCG revealed no other mutations and confirmed the T to A substitution. This single nucleotide polymorphism results in the amino acid substitution of glutamic acid to valine at position 110 (out of 127), changing its physicochemical properties and the ability to form aggregates as well as post-translational modifications. The obtained results provide grounds for further association studies of SNCG polymorphism in patients with various diseases of the nervous system.