Table 2. The frequency and causes of non-familial ataxia.

Causes of non-familial ataxias	684 patients (%)
Multiple system atrophy-cerebellar variant	470 (69)
Confirmed genetic causes	72 (11)
Sporadic adult onset ataxia of unknown etiology	46 (7)
Undiagnosed ataxia	53 (7)
Post-infectious cerebellar ataxia	14 (2)
Alcoholic cerebellar degeneration	11 (2)
Superficial siderosis	5 (1)
Toxic causes	5 (1)
Inflammatory causes	4 (1)
Paraneoplastic cerebellar degeneration	3 (<1)
Progressive ataxia with hypertropic olivary degeneration	1 (<1)