It has also been reported that upregulation of TLR4 signal pathway is involved in depression associated with other diseases, such as Alzheimer’s disease, obesity and alcohol addiction (Strekalova et al., 2015; Ledo et al., 2016; Anton et al., 2017; Wang et al., 2018). The gene discussed is TLR4; the disease is obesity due to melanocortin 4 receptor deficiency.