Association of c.+677 C>T (rs1801133) and c.+1298 A>C (rs1801131) MTHFR genetic variants with cardiometabolic and disease risk in systemic lupus erythematosus patients: A cross-sectional study.

Systemic lupus erythematosus (SLE) patients present a high prevalence of cardiometabolic risk, associated with worse clinical manifestations and mortality. Folate, an essential micronutrient that participates in vital immune cellular functions, could positively affect the cardiometabolic and disease risk in SLE, through the methylenetetrahydrofolate reductase (MTHFR) enzyme, which participates in the folate metabolism, where single nucleotide variants (SNVs) have been described as a potential genetic risk factor for SLE. The aim of this study was to determine the association of the c.+677 C>T (rs1801133) and c.+1298 A>C (rs1801131) MTHFR genetic variants with cardiometabolic risk and clinical disease variables in SLE patients. A case-control study was conducted on 394 unrelated Mexican-mestizo women: 199 with SLE according to the 1997 SLE-ACR criteria and 196 control subjects (CS). Folic acid and homocysteine levels were evaluated by immunoassays. Genotyping of MTHFR genetic variants was carried out by allelic discrimination. No significant differences were found for folic acid (p = .15) and homocysteine serum levels (p = .59) between groups. According to the CC c.+677 MTHFR genotype, this was associated with low cardiovascular disease (CVD) risk by the Castelli index (OR = 0.42; p = .03) in SLE patients. The TC (OR = 1.3; p = .03) and the TA (OR = 1.6; p < .01) haplotypes from c.+677 C>T plus c.+1298 MTHFR were associated with SLE risk, while the CC MTHFR haplotype (OR = 0.5; p = .01) was found as a non-risk factor for the disease. In conclusion, the TC and the TA MTHFR haplotypes are associated with disease risk; meanwhile, the CC c.+677 MTHFR genotype confers lower cardiometabolic risk in Mexican-mestizo SLE patients.