The etiological basis of HD is the deleterious expansion of polyglutamine encoding CAG repeats in Exon 1 of the Huntingtin (HTT) gene [3] leading to the ubiquitous expression of neurotoxic mutant Huntingtin (mHTT) and extensive degeneration of neurons in the cortex, thalamus, and most prominently the striatum [8–10]. The gene discussed is HTT; the disease is Huntington disease.