Clinically, polyQ disorders share several common features, including slow progression and late (adult) onset. They also exhibit anticipation, becoming earlier and/or more severe in succeeding generations, which is correlated with an intergenerational increase in repeat length. Each of the polyQ disorders affect specific but overlapping regions of the brain. The clinical pathologic features of spinobulbar muscular atrophy is relatively distinct, whereas that of dentatorubral-pallidoluysian atrophy overlaps HD, and SCAs (reviewed in Evert et al13). Involuntary movements, intellectual impairment, and emotional disturbances clinically characterize HD, while spinobulbar muscular atrophy is a rare progressive neuromuscular disorder characterized by proximal weakness, atrophy, and fasciculations. Dentatorubral-pallidoluysian atrophy is characterized by progressive dementia, myoclonic epilepsy, cerebellar ataxia, and choreoathetotic movements. All SCAs exhibit variable degrees of cerebellar and brainstem degeneration accompanied by progressive cerebellar ataxia associated neurological signs including ophthalmoplegia, dementia, and extrapyramidal signs.