Spinocerebellar Ataxia Type 14

Spinocerebellar ataxia type 14 (SCA14) is a rare mild subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term). It is characterized by slowly progressive ataxia, dysarthria and nystagmus.

Epidemiology

The disease has been reported in more than twenty families from Europe, the United States, and Australia.

Clinical description

Onset is usually in early adulthood while symptomatic disease onset may be from 10 to 70 years (mean = 33.9 years). In addition to cerebellar signs, hyperreflexia and decreased vibration sense are frequently observed. Some patients have cognitive impairment, parkinsonism characterized by rigidity, as well as focal dystonia, axial myoclonus, facial myokymia, choreic movement of hands and epilepsy.

Etiology

SCA14 is caused by missense mutations in the PRKCG gene (19q13.4) encoding protein kinase C gamma (PKC-gamma).

Prognosis

Prognosis is good. Some patients need supportive devices such as a cane or wheelchair for gait impairment. However, several affected patients have lived beyond 80 years of age.