Investigation of CLOCK rs1801260 Polymorphism of Circadian Genes in Schizophrenia Patients

Schizophrenia is a mental condition characterized by abnormalities in emotional reactivity, thought processes, and perception. Recent studies have suggested a possible connection between the pathophysiology of schizophrenia and the CLOCK gene, a key element of the biological circadian rhythm. The CLOCK rs1801260 polymorphism has not yet been studied in a Turkish population with schizophrenia, and the existing data are contradictory. This study aimed to compare and interpret the CLOCK rs1801260 polymorphism in terms of demographic characteristics, genotype, and allele distribution in patients with schizophrenia and healthy controls.

Deoxyribonucleic acid was purified from peripheral blood samples of 50 schizophrenia patients and 50 healthy control subjects, matched for age and sex. Genotyping was conducted by real-time polymerase chain reaction using the TaqMan Kit.

The odds of having the risk-associated TC or CC genotypes vs. the TT genotype were significantly higher in patients with schizophrenia compared to healthy controls (odds ratio (OR) = 2.92), and the risk C allele was also twice as prevalent in schizophrenia patients (OR = 2.00). The distributions of CLOCK rs1801260 genotypes (TT, TC, and CC) in the schizophrenia and the healthy control groups were independent of age and sex.

The presence of the TC or CC genotypes, or having the homozygous or heterozygous C allele, may pose a risk for schizophrenia in the Turkish population. If confirmed in larger and more diverse samples, the CLOCK rs1801260 polymorphism may serve as a genetic marker for identifying at-risk individuals and guiding individualized treatment strategies aimed at stabilizing circadian rhythm. Cite this article as: Yekayeva P, Türkgenç B, Gözler T, Yüksel I, Ulucan K, Tarhan N. Investigation of CLOCK rs1801260 polymorphism of circadian genes in schizophrenia patients. Eurasian J Med. 2026, 58(4), 1049, doi: 10.5152/eurasianjmed.2026.251049.