HTT and Huntington disease: Many groups have confirmed the role of PTM in the pathogenesis of HD, such as acetylation, phosphorylation, methylation, ubiquitination, and small ubiquitin modifier protein (SUMO) modification (Francelle et al., 2017; Sambataro and Pennuto, 2017), mainly at the 17 amino acid of the N-terminal Htt.