Previously, CD38 has been implicated to help regulate multiple chronic conditions/diseases, such as aging, obesity, and diabetes, through degradation of NAD (Marchetti et al., 2002; Canto et al., 2012; Camacho-Pereira et al., 2016; Chatterjee et al., 2018). The gene discussed is CD38; the disease is obesity due to melanocortin 4 receptor deficiency.