HTT and Cognitive impairment: HD is a mostly inherited neurodegenerative disease caused by a CAG trinucleotide repeat expansion in the Huntingtin (HTT) gene, which leads to progressive motor dysfunction, cognitive impairment, and psychiatric disturbance due to the gradual loss of neurons, predominantly in the striatum within the brain (MacDonald et al., 1993; Julien et al., 2007; Walker, 2007; Illarioshkin et al., 2018; Tabrizi et al., 2020).