Spinocerebellar Ataxia Type 15/16

Spinocerebellar ataxia type 15/16 (SCA15/16) is a rare subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term). It is characterized by cerebellar ataxia, tremor and cognitive impairment.

Epidemiology

Prevalence is unknown. Fewer than 80 patients affected by the disease have been identified to date.

Clinical description

Age of onset is from 20 to 66 years (mean age = 39.6 years).

Etiology

Genetic testing has shown that patients originally classified under SCA15 and SCA16 have the same subtype caused by a deletion in the inositol 1,4,5-triphosphate receptor 1 ITPR1 gene (3p26.1).

Prognosis

Prognosis is generally good and life-shortening events do not usually occur. Some patients live beyond 80 years of age.