ATN1 and Alzheimer disease: SUMO modification is also implicated in Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), as well as other CAG repeat diseases (SBMA, DRPLA, SCA1, and SCA7) (for review, see Krumova and Weishaupt, 2013; La Spada and Taylor, 2010; Wilkinson et al., 2010).