Animal and cell culture data strongly implicate SARM1-dependent axon loss in some peripheral neuropathies, glaucoma, Parkinson disease, and other conditions (Coleman and Hoke, 2020; Krauss et al., 2020; Loring and Thompson, 2020), and human genetic studies support its involvement in rare axonopathies involving NMNAT2 mutation (Huppke et al., 2019; Lukacs et al., 2019) and in ALS (Bloom et al., 2021; Gilley et al., 2021). This evidence concerns the gene NMNAT2 and Parkinson disease.