NR4A1 and obesity due to melanocortin 4 receptor deficiency: For example, the regulation of hormones such as leptin and insulin is a well-studied mechanism underlying obesity due to its role in metabolism and hunger signaling.69,70 While human and rat BMI GWAS identified genes encoding different hormone receptors and signaling proteins, the proximity of these genes in the molecular interaction network identifies the conserved role of neuronal hormone signaling.