- autosomal dominant, delayed age of onset

- gain-of-function mutation - trinucleotide repeat expansion disorder (--> anticipation)- produces a buildup of toxic protein aggregates in neurons- caudate atrophy- ↑ dopamine, ↓ GABA, ↓ Ach

- progressive dementia- loss of motor control (chorea)- mood disturbance

- common causes of death: aspiration pneumonia, head trauma