Machado-Joseph Disease Health Article

Definition

Machado-Joseph disease (MJD), also known as spin-ocerebellar ataxia Type 3 (SCA 3), is a rare hereditary disorder affecting the central nervous system, especially the areas responsible for movement coordination of limbs, facial muscles, and eyes. The disease involves the slow and progressive degeneration of brain areas involved in motor coordination, such as the cerebellar, extrapyramidal, pyramidal, and motor areas. Ultimately, MJD leads to paralysis or a crippling condition, although intellectual functions usually remain normal. Other names of MJD are Portuguese-Azorean disease, Joseph disease, Azorean disease.

Description

Machado-Joseph disease was first described in 1972 among the descendants of Portuguese-Azorean immigrants to the United States, including the family of William Machado. In spite of differences in symptoms and degrees of neurological degeneration and movement impairment among the affected individuals, it was suggested by investigators that in at least four studied families the same gene mutation was present. In early 1976, investigators went to the Azores Archipelago to study an existing neurodegenerative disease in the islands of Flores and São Miguel. In a group of 15 families, they found 40 people with neurological disorders with a variety of different symptoms among the affected individuals.

Another research team in 1976 reported an inherited neurological disorder of the motor system in Portuguese families, which they named Joseph disease. During the same year, the two groups of scientists both published independent evidence suggesting that the same disease was the primary cause for the variety of symptoms observed. When additional reports from other countries and ethnic groups were associated with the same inherited disorder, it was initially thought that Portuguese-Azorean sailors had been the probable disseminators of MJD to other populations around the world during the sixteenth century period of Portuguese colonial explorations and commerce. Presently, MJD is found in Brazil, United States, Portugal, Macau, Finland, Canada, Mexico, Israel, Syria, Turkey, Angola, India, United Kingdom, Australia, Japan, and China. Because MJD continues to be diagnosed in a variety of countries and ethnic groups, there are current doubts about its exclusive Portuguese-Azorean origin.