For individuals with severe hyperhomocysteinemia (e.g., >100 μmol/L), often linked to genetic disorders like classical homocystinuria (cystathionine beta-synthase deficiency) or severe MTHFR deficiency, aggressive therapy is mandated to prevent devastating neurological, ocular, and thrombotic complications. This evidence concerns the gene MTHFR and hyperinsulinemic hypoglycemia, familial, 4.