COMT and obesity due to melanocortin 4 receptor deficiency: Differentially expressed genes within cluster 13 were also enriched for common variant associations with BMI (Supplementary Tables 13 and 14), including associations in APOE, DOC2A, COMT and GABPB2. Taken together, these results highlight dysregulation of neurodevelopment, neurogenesis and neuronal oxidative phosphorylation as possible underlying mechanisms linking BSN deficiency to obesity (Supplementary Table 15).