The G allele, which was found in 15 of 29 patients who underwent immunological analysis and studies of brain morphometric parameters (in total, the G allele was detected in 20 of 48 patients with schizophrenia included in the study), was related to changes in cellular immunity in schizophrenia, including an increase in the content of CD3+ T cells, CD3+CD8+ cytotoxic T cells, a decrease in the number of CD3–CD16+CD56+ NK cells (natural killers). The gene discussed is NCAM1; the disease is schizophrenia.