The clinical, pathological and genetic aspects of sporadic late onset cerebellar ataxia: observations on a series of ten patients.

Ten patients with sporadic late onset cerebellar ataxia (LOCA) are described. The mean age of onset was 50.4 +/- 7.13 years. The important clinical features were gait ataxia, poor coordination of hands, intention tremors, exaggerated deep tendon reflexes, extrapyramidal symptoms and extensor plantar responses. Computerised tomography (CT) scanning in one patient showed a low density mid-line lesion, suggesting early cerebellar atrophy. Histopathological examination in one patient, clinically diagnosed as multiple sclerosis, revealed complete loss of Purkinje cells from the cerebellar folia with gliosis in the molecular layer and loss of small granular neurones. A marked loss of the neurones from the olivary nuclei with astrocytic proliferation was also seen. The disorder is probably genetically determined although a single Mendelian inheritance is unlikely in the absence of recurrence in the first degree relatives. Recurrence risks for gentic counselling are suggested.