Methylenetetrahydrofolate reductase 677 C -> T polymorphism, plasma folate, vitamin B-12 concentrations, and risk of preeclampsia among black Africanwomen from Zimbabwe

We conducted a case control study at Harare Maternity Hospital, Zimbabwe, W e genotyped a total of 171 cases with preeclampsia or eclampsia and 185 nor motensive control subjects for the methylenetetrahydrofolate reductase (MTH FR) 677 C --> T genotype. The mild-type allele frequency among cases and co ntrols was 91.2 and 91.3%, respectively. Only one subject (0.3%) was homozy gous for the 677 C --> T MTHFR genotype and this subject had preeclampsia, After adjustment for confounding factors, there was statistically no signif icant association between maternal MTHFR genotype and risk of preeclampsia (adjusted odds ratio = 1.0; 95% CI, 0.5-1.9), In addition, plasma homocyst( e)ine, vitamin B-12, and folate concentrations were not statistically diffe rent between normotensive control subjects with wild-type genotype as compa red with normotensive subjects who were heterozygous for the mutant allele, Conversely, there was a strong graded association between maternal plasma folate concentration and risk of preeclampsia, Women with plasma folate con centrations less than 5.7 nmol/L experienced a 10.4-fold increase in risk o f preeclampsia, There was no clear pattern of preeclampsia risk and Vitamin B-12 concentrations. (C) 2000 Academic Press.