Most recently, we have demonstrated that activation of leptin receptors (LepRs)-expressing neurons (LepRsARH) in the arcuate nucleus of hypothalamus (ARH) is the neural basis for type 1 diabetes (T1D) hyperglycemia, and the glucose-lowering effect of leptin is largely mediated through the inhibition of LepRsARH neurons [43]. This evidence concerns the gene LEP and type 1 diabetes mellitus.