PNPLA2 and obesity due to melanocortin 4 receptor deficiency: Concordant with several metabolic traits identified in the PheWAS such as obesity and cholesterol levels (Kanai et al., 2018; Pulit et al., 2019; Rask-Andersen et al., 2019), the QTL analyses identified two genes, PNPLA2 and USF1, whose functions are directly connected to those traits.