ATXN2 and spinocerebellar ataxia type 2: Degeneration of the substantia nigra, producingparkinsonism, and/or atrophy of the frontotemporal lobes may occursometimes.104,105 SCA2 is caused by a CAG repeatexpansion in the ataxin-2 (ATXN2) gene.106 Unlike the other polyQ diseases, SCA2 patients exhibit mainly cytoplasmic,rather than nuclear, inclusions.107