MTOR and obesity due to melanocortin 4 receptor deficiency: Studies have shown that the methylation rate of the TSC1 promoter in the hypothalamus of obese rats is significantly increased (Wang et al., 2020), and inhibition of this methylation downregulates the expression of mTOR, thereby activating autophagy in the hypothalamus and alleviating the obesity phenotype (Wang et al., 2017; Qi et al., 2019).