C3AR1 and obesity due to melanocortin 4 receptor deficiency: In the obesity study, perturbation of eight top obesity candidate causal genes for obesity - Zfp90, Lpl, Tgfbr2, C3ar1, Gpx3, Gas7, Lactb, and Gyk - was found to alter adiposity or fat pad mass in knockout or transgenic mouse models via modulation of genes involved in metabolic pathways and a liver network of genes involved in lipid metabolism [51].