The principal clinical and pathological distinction between alcohol-associated liver disease (ALD) and metabolic dysfunction-associated steatotic liver disease (MASLD)—beyond the absence of significant alcohol intake and the frequent presence of obesity in MASLD—relates to the differential elevations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). This evidence concerns the gene GPT and obesity due to melanocortin 4 receptor deficiency.