Machado-Joseph Disease

Inherited ataxia

Machado-Joseph disease, known as spinocerebellar ataxia (SCA) type 3, is one of the inherited ataxia disorders. People with ataxia have loss of muscle control, resulting in lack of balance and coordination. Machado-Joseph disease has three forms that differ in when they begin and how severe they become.

Machado-Joseph disease occurs most frequently among people of Portuguese or Azorean descent. On the island of Flores in the Azores, it occurs in 1 in 140 people. However, Machado-Joseph disease may occur in any individuals of any ethnic background. It has been linked to a genetic defect on chromosome 14.

Symptoms
The different types of Machado-Joseph disease begin at different ages and have different ranges of symptoms.

Type I (MJD-I)
• Begins between 10 and 30 years of age
• symptoms worsen quickly
• severe muscle spasms (dystonia) and stiffness (rigidity)

Type II (MJD-II)
• Begins between 20 and 50 years of age
• symptoms worsen gradually over time
• continuous, uncontrolled muscle spasms (spasticity)
• difficulty walking due to muscle spasms (spastic gait)
• abnormal reflexes

Type III (MJD-III)
• Begins between 40 and 70 years of age
• symptoms worsen slowly over time
• muscle twitching
• numbness, tingling, cramps, and pain in the hands, feet, and arms and legs
• loss of muscle tissue (atrophy)

Many individuals with Machado-Joseph disease of any type have vision problems such as double vision (diplopia) and inability to control eye movements, as well as trembling of their hands and problems with balance and coordination.

Diagnosis
Diagnosis of Machado-Joseph disease is based on the symptoms the individual is experiencing. Since the disorder is inherited, it is important to ask questions about relatives who may have had symptoms, including when the symptoms began and how quickly they developed. A genetic test for the specific genetic defect on chromosome 14 may be done to confirm the diagnosis.

Treatment
There is as yet no cure for Machado-Joseph disease, or way to stop its symptoms from becoming worse. Some medications may help relieve symptoms. Baclofen (Lioresal) or botulinum toxin (Botox) can help reduce muscle spasms and dystonia. Physical therapy and assistive equipment can help individuals with movement and daily activities.

Sources:
- "Machado-Joseph Fact Sheet." Disorders. 13 Feb 2007. National Institute of Neurological Disorders and Stroke. 15 Feb 2007 <http://www.ninds.nih.gov/disorders/machado_joseph/detail_machado_joseph.htm>.
- "Machado-Joseph Disease." Index of Rare Diseases. National Organization for Rare Disorders. 15 Feb 2007 <http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Machado-Joseph%20Disease>.