Previous studies have shown that circulating pipecolate levels were strongly associated with obesity and metabolic syndrome and had the ability to predict the risk of future T2DM, HG, increasing insulin secretion in early IR, and had a lesser role in the setting of advanced IR or T2DM (Wang et al., 2013; Libert et al., 2018). The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.