We examined five genes in the OCM pathway, including two loci of MTHFR gene polymorphisms, C677T (rs1801133) and A1298C (rs1801131), both are associated with MTHFR enzymatic deficiency resulting in increased homocysteine concentrations [33,34]. The gene discussed is MTHFR; the disease is hyperinsulinemic hypoglycemia, familial, 4.