Azorean disease of the nervous system.

We studied a family of Portuguese ancestry from the Azores who suffered a progressive neurologic disease characterized by gait ataxia, features similar to Parkinson's disease in some patients, limitation of eye movements, widespread fasciculations of muscles, loss of reflexes in the lower limbs, followed by nystagmus, mild cerebellar tremor and extensor plantar responses. Two post-mortem examinations revealed loss of neurons and gliosis in the substantia nigra, nuclei pontis (and in the putamen in one case) as well as in the nuclei of the vestibular and other cranial nerves, columns of Clarke and anterior horns, in the spinal cord there were also loss of fibers in the fasciculi gracilis and mild changes in the pyramidal tracts. Comparison of the disease in this family with the findings reported in three families of similar ancestry, previously thought to have different disorders, suggests that they may all represent a single genetic entity with variable expression.