Suicide attempt in mental disorders (MeDi): Association with 5-HTT, IL-10 and TNF-alpha polymorphisms

Mental disorders (MeDi) and suicide attempts (SA) are influenced by environmental and genetic factors. Genetic polymorphism studies have identified some candidate genes for suicidal behaviour in people with MeDi.

To evaluate MeDi and SA in relation to the presence of rs2020933 (5-HTT), rs1800871 (IL-10) and rs1800629 (TNF-α) polymorphisms.

A questionnaire for identification and general data, a brief quality of life assessment (WHOQOL-brief), the scale of suicide ideation by Beck and the MINI International Neuropsychiatric Interview were used in this study. DNA was obtained using buccal mucosa swab samples, and genotyping was performed using real-time polymerase chain reaction. A total of 306 patients were assessed with MeDi; 161 patients had MeDi and a history of SA, and 145 patients had MeDi and no history of SA. The study had 175 subjects in the control group.

The TNF-α rs1800629 -308A/G genotype was significantly associated with function as a protection factor in the control group compared with MeDi without SA. The TNF-α rs1800629 -308G allele appeared as risk factor for MeDi compared to the control group, for female gender. Additionally, the -308A/G + A/A genotype appeared as protection factor for the control group compared to the group with MeDi. For TNF-α, the -308G allele appeared as risk factor for the number of SA (1 time) compared to the control group.

The IL-10 (rs1800871) and 5-HTT (rs2020933) SNPs were considered to have inadequate statistical power. The rs1800629 (TNF-α) polymorphism may be associated with MeDi without SA, MeDi in females and the number of SA (1 time) in the studied group.