Do you test for genetic ataxias prior to making a diagnosis of cerebellar-type Multiple System Atrophy?

It depends. If there is no family history of ataxia, neuropathy, significant dysautonomia, or RBD, then I do not. I might consider getting a DaT scan or Synone skin testing to further reinforce the diagnosis of MSA-C (knowing that a DaT scan may be negative here, too). If, on the other hand, there is a younger age at onset, no RBD, the presence of neuropathy, and mild, if any, dysautonomia, then I would consider genetic testing for genetic causes of ataxia.