A recent study investigated the relationship between AST/ALT ratio and incident T2DM in populations with or without obesity and demonstrated that non-obese individuals with AST/ALT ≤ 0.875 have a higher risk of developing T2DM than obese individuals with AST/ALT ≥ 0.875 (38). The gene discussed is GPT; the disease is obesity due to melanocortin 4 receptor deficiency.