This premise is supported by reports linking the ALT/AST ratio to the presence of nonalcoholic fatty liver disease,[9,10] a condition that shares common risk factors, such as obesity and insulin resistance, with OSA.[11] We hypothesized that the ALT/AST ratio might serve as a more specific indicator reflecting the metabolic disturbances underlying OSA. This evidence concerns the gene GPT and obesity due to melanocortin 4 receptor deficiency.