Moreover, there is increasing evidence that CYP2E1 plays a significant role in obesity-associated nonalcoholic fatty liver disease (NAFLD), in particular by favoring the progression of simple fatty liver (i.e., steatosis) to nonalcoholic steatohepatitis (NASH) [2,3]. Here, CYP2E1 is linked to obesity due to melanocortin 4 receptor deficiency.