Finally, upregulation of the expression of certain microRNAs in muscle of humans with obesity impairs expression of muscle mitochondrial proteins (Tran et al., 2016), as well as that of muscle insulin-like growth factor-1 (IGF-1) that regulates protein anabolism in muscle (Sullivan et al., 2020). The gene discussed is IGF1; the disease is obesity due to melanocortin 4 receptor deficiency.