Cerebellar and parkinsonian phenotypes in multiple system atrophy: similarities, differences and survival

Multiple system atrophy (MSA) is a neurodegenerative disease with two motor phenotypes: parkinsonian (MSA-P) and cerebellar (MSA-C). To elucidate whether in addition to the motor abnormalities there are other significant differences between these phenotypes, we performed a retrospective review of 100 patients (61 males, 39 females) with a diagnosis of possible (12 %), or probable (88 %) MSA. Four patients eventually had post-mortem confirmation (i.e., definite MSA). Sixty percent were classified as having MSA-P and 40 % as MSA-C. MSA-C and MSA-P patients had similar male prevalence (60 %), age of onset (56 ± 9 years), and frequency of OH (69 %). Brain MRI abnormalities were more frequent in MSA-C patients (p < 0.001). Mean survival was 8 ± 3 years for MSA-C and 9 ± 4 years for MSA-P patients (p = 0.22). Disease onset before 55 years predicted longer survival in both phenotypes. Initial autonomic involvement did not influence survival. We conclude that patients with both motor phenotypes have mostly similar survivals and demographic distributions. The differences here identified could help counseling of patients with MSA.