ALDH1A1 and obesity due to melanocortin 4 receptor deficiency: Specific inhibitors have been sought for ALDH1A1, ALDH1A1, and ALDH1A3 for treatment of Parkinson’s disease, obesity, cataracts, and various types of cancer (Huddle et al., 2018; Morgan and Hurley, 2015; Quattrini et al., 2020).