Among the most frequently observed genes in metabolism-related processes, examples include AhR and LXR in AOPs associated with steatosis (e.g., AOP IDs 34, 57, 58 and 232), PPARα in AOPs describing lipid metabolism alterations (e.g., AOP ID 166), and ERα in an AOP related to obesity (AOP ID 493). Here, PPARA is linked to obesity due to melanocortin 4 receptor deficiency.