The occurrence of T2DM is related to changes in gut microbiota composition, which caused activation of a network of inflammatory signal pathways via the lipopolysaccharides (LPS) and CD14/toll-like receptor 4- (TLR4-) dependent pathway, and then made the body in a state of low-grade inflammation; ultimately, T2DM came into being [49, 50]. The gene discussed is TLR4; the disease is type 2 diabetes mellitus.