In patients with autoimmune thyroid disease, the expression and activation of TLR2, 3, and 9 are significantly increased.418,419 In addition, it has been reported that TLR9 negatively regulates pancreatic islet development and β cell differentiation, providing new directions for diabetes prevention and treatment strategies.420 In diet-induced obesity, TLR2 and TLR4 inhibit the replication of β cells and affect the nuclear abundance of the cell cycle regulators cyclin D2 and Cdk4. The gene discussed is TLR2; the disease is obesity due to melanocortin 4 receptor deficiency.