HAP1 and Spinocerebellar ataxia type 3: It is postulated that STB/HAP1 acts as a protective barrier against apoptosis and cell death by raising the threshold of susceptibility to neurodegeneration and providing enhanced stability to neurons in HD or several other neurodegenerative disorders (NDs), such as spinal and bulbar muscular atrophy, spinocerebellar ataxia type 3 (SCA3), SCA17, and Joubert syndrome (Li et al., 2003; Fujinaga et al., 2004; Takeshita et al., 2006, 2011; Metzger et al., 2008; Islam et al., 2017).