Several studies have reported the potential association between the most common allelic variants of MTHFR gene (C677T and A1298C) and susceptibility to many clinical diseases, such as gastric cancer, hepatocellular carcinoma, NAFLD, neural tube defects, acute lymphoblastic leukemia and renal/heart failure [11, 25, 26, 38–42]. The gene discussed is MTHFR; the disease is acute lymphoblastic leukemia.