Although the mechanisms whereby obesity contributes to NAFLD remain unclear, recent studies identified key molecular mediators such as 11β-hydroxysteroid-dehydrogenase 1, fibroblast growth factor-21 and neurotensin, which could potentially contribute to the development of NAFLD in patients with obesity [42,43,44,45]. The gene discussed is FGF21; the disease is obesity due to melanocortin 4 receptor deficiency.