Genetic association studies have shown that methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with RHD [32] and other studies have suggested genetic associations between promoter polymorphisms in angiotensin-converting enzyme (ACE) and interleukin 10 (IL-10) and RHD [33, 34]. Here, MTHFR is linked to rheumatic heart disease.