Huntington’s disease (HD) is a rare autosomal dominant neurodegenerative disorder caused by an expansion of cytosine-adenine-guanine (CAG) repeats (≥ 36) in the exon 1 of the Huntingtin (HTT) gene, encoding for a stretch of polyglutamine (polyQ) in the Huntingtin protein [22]. The gene discussed is HTT; the disease is Huntington disease.