HD is an inherited neurodegenerative disorder with hallmarks such as progressive motor, cognitive and psychiatric dysfunction (Paulsen et al., 2001; Tabrizi et al., 2013) caused by an increased polyglutamine (PolyQ)-encoding CAG repeat (>36) in exon 1 of the huntingtin gene (HTT) (MacDonald et al., 1993). The gene discussed is HTT; the disease is Huntington disease.