For instance, PD-associated mutations in Parkin, PINK1 and FBXO7, all of which impair mitophagy, reduce cellular NAD+ levels that is suggested via PARP activation (Burchell et al., 2013; Lehmann et al., 2016; 2017; Delgado-Camprubi et al., 2017). Here, PRKN is linked to Parkinson disease.