The association of the TLR3 SNP rs3775291 with schizophrenia is influenced by age.

Background: Toll-like receptor 3 (TLR3) plays an important role in the pathogenesis of schizophrenia and the Methods: A case-control study was performed that included 394 patients with schizophrenia and 445 healthy controls. Peripheral venous blood was collected, whole-genome DNA was extracted, and rs3775291 polymorphisms were detected using PCR and direct sequencing. Differences in distribution of allele and genotype frequencies between the two groups were compared using co-dominant, dominant, and recessive genetic models. The effects of sex, age, and family history were also analysed. Results: Allele and genotype frequencies of rs3775291 were not associated with schizophrenia overall, nor were they associated with schizophrenia in the different sex or family history groups (P > 0.05). However, in the < 40 years age group, co-dominant and dominant model analyses showed that the frequency of TC and CC genotypes in patients with schizophrenia was significantly higher than that in the control group (P < 0.05), and TC and CC genotypes were associated with susceptibility to schizophrenia. There was no significant difference among people older than 40 years. Conclusion: The effect of rs3775291 on schizophrenia was age-related, TC and CC genotypes were associated with susceptibility to schizophrenia in younger individuals, and the TT genotype had a protective effect regarding schizophrenia.