INS and obesity due to melanocortin 4 receptor deficiency: We discovered that, compared with REGγ AKO mice, the AAV shKlf15‐treated REGγ AKO mice exhibited more severe obesity‐related phenotypes, including increased body weight, increased fat mass, increased glucose tolerance, increased insulin tolerance, decreased oxygen consumption, increased carbon dioxide production, increased fat and liver weights, and increased fat volume (Figure S7d–l, Supporting Information).