Spinocerebellar Ataxia Type 14

SCA14 was described in a single four-generation Japanese kindred with autosomal dominant cerebellar ataxia. The age of onset ranges from 3 to 42 years of age. Initial symptoms are ataxia of gait in may cases. However, in several individuals with an earlier onset initial signs include an irregular tremulousness of the neck and axial musculature, described as intermittent axial myoclonus, followed soon afterward by mild ataxia. Progression of disease is usually slow. Other findings on examination included gaze-evoked nystagmus, saccadic visual pursuits, upper and lower limb ataxia, dysarthria, and reduced Achilles reflexes. Neuroimaging studies reveal cerebellar atrophy. The gene for SCA14 encoded the protein kinase C gamma. The diagnosis is established by demonstration of one of several mutations indentified as pathogenic in this gene.