PNPLA3 and obesity due to melanocortin 4 receptor deficiency: Different factors have been involved in this heterogeneity like components of metabolic syndrome—especially obesity, T2DM and arterial hypertension, menopausal status in females, ageing, etc. In this complex landscape, genetic background and in particular the presence of the PNPLA3 rs738409 C > G variant could account for some variability.