Spinocerebellar ataxia (SCA) comprises more than 40 types of similar inherited brain disorders. SCA affects your cerebellum, a part of your brain vital to physical movement. It causes problems with coordination and movement. There’s no cure, so treatment aims to relieve symptoms and improve function.
Ataxia is a degenerative condition that affects your nervous system. It involves problems with coordination and movement. There are many different kinds of ataxia with varying causes and symptoms.
Spinocerebellar ataxia (SCA) is a group of inherited brain disorders. It affects your cerebellum, a part of your brain vital to coordination of physical movement, and sometimes your spinal cord. This inherited condition worsens over time and causes specific problems with coordination, usually affecting:
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Experts have discovered more than 40 types of SCAs so far, and that number may increase. They identify types by number (for example, spinocerebellar ataxia type 1, spinocerebellar ataxia type 2 and so on).
All types of SCAs have similar causes and symptoms. The numbers indicate the order in which experts discovered the associated mutations. In other words, SCA1 was the first type linked to an inherited chromosomal problem. SCA2 was the second, etc.
The most common type is spinocerebellar ataxia type 3, also known as Machado-Joseph disease.
SCA is rare. It affects about 1 to 5 people per 100,000.
An inherited gene mutation causes SCA. Experts have linked this specific gene to many types of spinocerebellar ataxias, but not all.
Some types of SCAs occur because a segment of DNA abnormally repeats several times (called trinucleotide repeat expansion).
The condition is usually inherited in an autosomal dominant fashion. This means that it takes only one copy of the mutated gene from one biological parent to cause the condition. Therefore, when a person with SCA has children, each child has a 50% chance of inheriting the mutated gene.
There are also autosomal recessive spinocerebellar ataxias. In these cases, a person inherits an abnormal gene from both biological parents, who are generally asymptomatic.
Signs and symptoms of SCA usually appear after age 18 and slowly worsen over several years.
Spinocerebellar ataxia symptoms often include:
A healthcare provider might diagnose SCA based on:
Genetic testing can confirm many types of SCA. However, some types aren’t associated with a specific mutation, so experts can’t confirm all types of SCAs this way.
Genetic testing is also available for people who think they might be carrying an SCA genetic mutation. Testing can help them with decisions about family planning. Healthcare providers also can test babies before they’re born with prenatal testing.
There’s no known cure for SCA. Treatment aims to reduce symptoms and improve functioning.
Spinocerebellar ataxia treatment may include:
Researchers are still exploring ways to help people manage and treat SCA.
There aren’t any proven strategies to prevent SCA. Some families who know they carry the mutation may choose not to have children. That’s the only way to prevent passing down the condition to the next generation.
Ataxia life expectancy varies widely, depending on the type and severity. Sadly, many cases of SCA cause premature death.
How quickly the condition progresses also depends on type and severity. As a result, genetic testing may help with predicting course in addition to making a definitive diagnosis. Many people need a wheelchair within 10 to 15 years of their first symptoms. It’s common for people with SCA to eventually need help with daily tasks.
If you have spinocerebellar ataxia (SCA), consider asking your healthcare providers the following questions:
A diagnosis of spinocerebellar ataxia raises many questions and emotions. Some of the following strategies may help you cope:
A note from Cleveland Clinic
Spinocerebellar ataxia (SCA) is a group of inherited brain disorders. The various types all cause issues with coordination and movement, which worsen over time. If you have SCA, talk to your healthcare provider about ways to relieve symptoms and improve function.
Last reviewed by a Cleveland Clinic medical professional on 08/29/2022.
Learn more about our editorial process.