Genetic mutations in ABCA1 (Tangier disease), LCAT (familial lecithin:cholesterol acyltransferase deficiency), ApoA1 (familial apolipoprotein (Apo) A1 deficiency), and UBIAD1 (Schnyder corneal dystrophy, SCD) all result in corneal accumulation of lipids including cholesterol. Here, APOA1 is linked to hyperinsulinemic hypoglycemia, familial, 4.