Machado-Joseph disease (MJD), also referred to as spinocerebellar ataxia Type 3 (SCA3), is one of approximately 30 recognized, dominantly inherited forms of ataxia. Ataxia is a general term meaning lack of muscle control or coordination.
Soon after the gene defect was discovered, a hereditary ataxia in European families known as SCA3 was found to be caused by the exact same mutation. Thus, SCA3 and MJD are the same disorder.
Physicians diagnose MJD by recognizing the symptoms of the disease and by taking a family history. They ask detailed questions about family members who show (or showed) symptoms of the disease, the kinds of symptoms seen in these relatives, the age(s) of disease onset, and the progression and severity of symptoms. A definitive diagnosis of MJD can be made only with a genetic test. The genetic test for MJD (SCA3) is highly accurate.
Those who are at risk for MJD (i.e. have an affected parent) but do not have any symptoms can undergo presymptomatic testing to determine whether they carry the disease allele (and thus will later develop the disease). Obtaining presymptomatic testing is a highly personal decision that at-risk individuals should make only after fully considering the potential pros and cons. Many at-risk persons choose not to undergo this test out of concern for job discrimination and difficulty in obtaining or maintaining insurance, among other reasons.
MJD is incurable, but some symptoms of the disease can be treated. The treatment options considered are levodopa therapy (used in treating individuals with Parkinson’s disease), botulinum toxin and physiotherapy.
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