Huntington’s disease, a neurodegenerative disorder, is caused by CAG (cytosine, adenine, guanine) expansion in exon 1 of the huntingtin (Htt) gene, leading to progressive brain dysfunction with signs of psychiatric disorder, muscle coordination impairment and cognitive decline (Matlahov & van der Wel, 2019 ▸). This evidence concerns the gene HTT and Mental deterioration.