RESUMO
Objective To investigate gene-gene interactions of suicidal behavior with single-nucleotide-polymorphism (SNP) in MAOA ,GAD1 and 5-HTR2C by multifactor dimensionality reduction .Methods For this case-control study ,six SNPs were captured in related genes and detected in blood samples obtained from 21 patients with suicidal behavior and 50 healthy individuals .The genotype frequency and allele frequency as well as the Hardy-Weinberg equilibrium (HWE) ,tests were performed and compared by plink software .The gene-gene interactions models were built by the MDR software .Results The HWE test for case group showed that rs3813928 rs518147 of 5-HTR2C gene was not in line with HWE ( P< 0 .05) .However ,the additive model analysis after adjustment by gender indicated that the polymorphism had a positive correlation with suicidal behavior in case group .The case and control groups differed significantly only in genotype frequencies of 5-HTR2C gene (χ2 =6 .18 , P=0 .04) .There was no significant difference in allele and genotype frequencies of the other genes ( P>0 .05) .The best combination model of MDR was rs5953210-rs769391 OR=20 .19 ,95% CI 4 .19-97 .38 , P<0 .01 ,with significant interaction . Conclusion The 5-HTR2C gene rs3813928 and rs518147 polymorphisms may play an important role in the susceptibility to suicidal behavior .The combination of MAOA with GAD1 has a significant interaction which may increase the risk of suicidal behavior .