MTHFR mutations and marginal nutrition affect vitamin and mineral homeostasis in diabetic retinopathy patients.25 Raising the levels of antioxidants B6, B12, and L-methylfolate in the central nervous system (CNS) is known to reduce mitochondrial oxidative stress while lowering homocysteine.18,26 It is likely that a similar mechanism is at work in these DR + PM patients with impaired homocysteine (Hcy) metabolism. Here, MTHFR is linked to diabetic retinopathy.