FGF21 and obesity due to melanocortin 4 receptor deficiency: While earlier rodent studies found rapid increment in circulating FGF-21 and hepatic FGF-21 mRNA levels in response to fasting [15], human data demonstrated higher levels of FGF-21 in obesity-related conditions like NAFLD compared to the healthy controls [14] suggesting the presence of FGF-21 resistance in NAFLD [14,16].