In both AD and SCA3, oligodendrocyte dysfunction in animal models recapitulates white matter abnormalities seen in human patients (Roher et al., 2002; Wu et al., 2017; Inada et al., 2020; Park et al., 2020; Faber et al., 2021; Haas et al., 2021; Kenigsbuch et al., 2022; Schuster et al., 2022c). The gene discussed is ATXN3; the disease is Alzheimer disease.