title: Multiple system atrophy of the cerebellar type: clinical state of the art.
abstract: Multiple system atrophy (MSA) is a late-onset, sporadic neurodegenerative disorder clinically characterized by autonomic failure and either poorly levodopa-responsive parkinsonism or cerebellar ataxia. It is neuropathologically defined by widespread and abundant central nervous system α-synuclein-positive glial cytoplasmic inclusions and striatonigral and/or olivopontocerebellar neurodegeneration. There are two clinical subtypes of MSA distinguished by the predominant motor features: the parkinsonian variant (MSA-P) and the cerebellar variant (MSA-C). Despite recent progress in understanding the pathobiology of MSA, investigations into the symptomatology and natural history of the cerebellar variant of the disease have been limited. MSA-C presents a unique challenge to both clinicians and researchers alike. A key question is how to distinguish early in the disease course between MSA-C and other causes of adult-onset cerebellar ataxia. This is a particularly difficult question, because the clinical framework for conceptualizing and studying sporadic adult-onset ataxias continues to undergo flux. To date, several investigations have attempted to identify clinical features, imaging, and other biomarkers that may be predictive of MSA-C. This review presents a clinically oriented overview of our current understanding of MSA-C with a focus on evidence for distinguishing MSA-C from other sporadic, adult-onset ataxias.
authors.affiliation: Ataxia Unit, Laboratory for Neuroanatomy and Cerebellar Neurobiology, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lin
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Hermann
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Schmahmann
mesh_terms: D000818:Animals; D002524:Cerebellar Ataxia / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D019578:Multiple System Atrophy / Q000378:metabolism* / Q000628:therapy; D020734:Parkinsonian Disorders / Q000378:metabolism / Q000628:therapy; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D051844:alpha-Synuclein
keywords: ataxia; cerebellum; idiopathic late-onset cerebellar ataxia; multiple system atrophy; sporadic adult-onset ataxia of unknown etiology