FGF21 and metabolic dysfunction-associated steatotic liver disease: Notably, the dysregulation in FADS1 influences hepatic lipid homeostasis by modulating the PPARα-FGF21 axis [33] and a decreased hepatic FADS1 expression, associated with low levels of long-chain PUFAs, have been detected in subjects with nonalcoholic fatty liver disease (NAFLD).