Machado-Joseph disease gets its name from two families of Portuguese/Azorean descent who were among the first families described with the unique symptoms of this disease. Characteristics of the disease include clumsiness and weakness in the arms and legs, spasticity, and a staggering, lurching gait that is easily mistaken for drunkenness. The disease is incurable, but some of its symptoms can be treated.
Machado-Joseph disease (MJD) is a rare hereditary ataxia. Ataxia is a general term meaning lack of muscle control. Another name for Machado-Joseph disease is spinocerebellar ataxia type 3.
The name Machado-Joseph comes from two families of Portuguese/Azorean descent who were among the first families described with the unique symptoms of the disease in the 1970s. The prevalence of Machado-Joseph disease is still highest among people of Portuguese/Azorean descent. For immigrants of Portuguese ancestry in New England, the prevalence is around 1 in 4,000.
The highest prevalence of Machado-Joseph disease in the world, about 1 case per 140 people, occurs on the small Azorean island of Flores. Recently, researchers have identified Machado-Joseph disease in several family groups who are not of obvious Portuguese descent, including an African American family from North Carolina, an Italian American family, and several Japanese families. On a worldwide basis, Machado-Joseph disease is the most prevalent autosomal dominant inherited form of ataxia, based on DNA studies.
Types of Machado-Joseph disease are determined by a person's age (when symptoms first appear) and the range of symptoms. Types of Machado-Joseph disease include:
- Type I
- Type II
- Type III.