Reference Work Entry

Encyclopedia of Molecular Mechanisms of Disease

pp 168-169

Ataxias, Sporadic

  • Thomas KlockgetherAffiliated withDepartment of Neurology, University Hospital Bonn


Idiopathic cerebellar ataxia; IDCA

Definition and Characteristics

The sporadic ataxias are a heterogeneous group of adult-onset ataxia disorders that have a defined acquired cause (acquired or symptomatic sporadic ataxias) or occur without a discernible cause (sporadic ataxia of unknown etiology, SAOA) [1]. The latter category has been recently defined and distinguished from multiple system atrophy (MSA). The major categories of acquired ataxias are alcoholic cerebellar degeneration (ACD) [2] and paraneoplastic cerebellar degeneration (PCD) [3]. Sporadic ataxias are characterized by progressive cerebellar ataxia without major accompanying symptoms. Disease severity and progression rate are variable and partly depend on the underlying cause. In contrast to SAOA, which usually starts insidiously, ACD and PCD may have a subacute onset.


A recent population-based study of SAOA found a prevalence rate of 9.4:100,000. Prevalence ra ...

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