A large Brazilian family, of white ancestry, in which several members presented a spinocerebellar ataxia, was studied. Informations were obtained covering six generations, in a total of 337 related individuals. 116 of them were examined by the author. 18 presented the disease, and of these 10 were alive at the time of the study. Besides them, by her descendents, it was possible to find a carrier of the gene, who died in a preataxic age.
The disease is transmitted by an autosomal dominant gene, and appears at the age of 38.33 ± 1.74 years. Cerebellar, posterior chord and pyramidal alterations were present in the sick persons. Almost all the patients presented disturbances of the temperature sense. The disease had not lowered the viability and fertility of the affected persons.