MTHFR C677T Genotype clinical trials

Pilot Evaluation of the Effect of Riboflavin Supplementation on Blood Pressure and Possible Effect Modification by the MTHFR C677T Genotype

Hypertension, which results from a combination of multiple lifestyle and genetic factors, is a global public health problem affecting 1 billion people worldwide. The identification of cheap treatment interventions without adverse side effects would be hugely advantageous particularly in low-income settings with high prevalence of hypertension such as sub-Saharan Africa where up to 46% of adults are affected. Emerging evidence links a functional polymorphism in the MTHFR gene (rs1801133 C677T), encoding the folate-metabolising enzyme methylenetetrahydrofolate reductase to high blood pressure in adults. Variation at rs1801133 is relatively common and has 3 genotypes; homozygous "normal" CC, heterozygous CT and homozygous "variant" TT genotypes. Of these genotypes, the homozygous "variant" TT is more strongly associated with a higher BP. The precise mechanism by which MTHFR is associated with BP remains unclear. It has been recently shown in 3 separate randomized controlled trials that BP is highly responsive to riboflavin and that this response is differential by MTHFR rs1801133 genotype. In all these clinical trials, significant reduction in both systolic and diastolic blood pressure was observed in the homozygous variant TT genotype and an intermediate effect seen in those with the heterozygous CT genotype. The aim of this study is to evaluate the effect of riboflavin supplementation on blood pressure in a riboflavin-deplete population as well as comparing plasma riboflavin status before and after supplementation. This will be achieved by conducting a randomized single-blind placebo controlled trial over a period of 16 weeks. The Investigators will use the Keneba biobank to invite about 100 adults with the CT genotype and a similar number of age-, sex and village-matched CC homozygotes. Participants within each of the groups will be randomized to receive either riboflavin (5mg/d) or a matching placebo which would be supplied on a weekly basis. Blood sample, blood pressure measurement, socio-demographic data and their anthropometric measurements (height, weight, waist and hip circumference and body composition by BIA) will be taken during the initial visit. An additional blood sample will be taken at the end of the study whilst additional BP measurements will be taken respectively at 8 weeks and at the end of the intervention. The possibility that riboflavin deficiency represents a new, easily-correctible causal factor in hypertension in sub-Saharan Africa would require further large-scale interventions if this pilot study yields encouraging results.