The remaining causal genes provide additional mechanistic insights: CYP27A1 encodes cholesterol 27-hydroxylase, and its deficiency has been associated with retinal oxidative stress and vascular changes resembling diabetic retinopathy in experimental models [53]; GPD2 encodes a key enzyme in the glycerol-3-phosphate shuttle, with evidence showing its protective role against diabetic complications through mitochondrial metabolism regulation [54]; and FBN2 encodes an extracellular matrix protein, though its specific role in diabetic retinopathy requires further validation [55]. The gene discussed is GPD2; the disease is diabetic retinopathy.