ATXN3 and multiple system atrophy, cerebellar type: Interestingly, this spectrum of severity from the milder form of CCAS in ET and SCA3 to more severe forms in SCA2 and MSA-C also corresponds to the severity spectra of the cerebellar cortex degenerative changes, centered around PC cells (PC loss, heterotopic PC, PC dendritic, and axonal and synaptic changes) described on pathology in SCA2, MSA-C, SCA3, FA, and ET (4).