Autosomal dominant system degeneration in Portuguese families of the Azores Islands. A new genetic disorder involving cerebellar, pyramidal, extrapyramidal and spinal cord motor functions.

We studied 40 patients in 15 families from the Portuguese Azores Islands. Each family was affected by an autosomal dominant genetic disorder. Symptoms began between ages 20 and 50. Ataxia, ophthalmoplegia, pyramidal signs, dystonia, rigidity, and distal atrophy were the major clinical findings. Evidence suggested that this was a single genetic disease, with variable phenotypic expression. Machado disease, nigrospinodentatal degeneration with nuclear ophthalmoplegia, and autosomal dominant striatonigral degeneration may be variations of this same genetic disease.