Genetic risks of schizophrenia identified in a matched case-control study

Background: Genetic association studies of schizophrenia may be confounded by the pathological heterogeneity and multifactorial nature of this disease. We demonstrated previously that combinations of the three functional single nucleotide polymorphisms (SNPs) rs10770141 of tyrosine hydroxylase (TH) gene, rs4680 of catechol-O-methyltransferase (COMT) gene, and rs1800497 of dopamine D2 receptor (DRD2) gene may be associated with schizophrenia onset, and we tested those associations herein. Methods: We conducted a secondary study of 2,542 individuals in age- and sex-matched case-control populations. The schizophrenia diagnosis was based on the DSM-IV. To reduce the influence of confounders (age and sex), we performed a propensity score matching analysis. Genotyping and associative analyses of rs10770141, rs4680, and rs1800497 with schizophrenia were performed. Results: We analyzed 1,271 schizophrenics (male/female: 574/698; age 47.4±13.9 years) and 1,271 matched controls (male/female: 603/669; age 46.5±13.4 years). The estimated odds ratios (ORs) were 1.245 (p