Many observational studies have found that the higher the Hcy level, the greater the risk of CVD-related disease and mortality in CKD patients.[100] However, RCTs have found that the use of folate supplements to reduce Hcy concentration did not lower CVD risk.[101–103] Moreover, MTHFR C677T has been shown to reduce MTHFR activity and increase in vivo Hcy concentrations.[13] Additional pathological and physiological studies are required to investigate the relationship between renal function and MTHFR C677T. Here, MTHFR is linked to chronic kidney disease.