Spinocerebellar ataxia 5 (SCA5) is one of the many spinocerebellar ataxias, which are inherited conditions that cause degeneration of the spinal cord and cerebellum. SCA5 almost exclusively affects the cerebellum. It is considered to be a mild form that progresses slowly. The age of onset is usually between the ages of 20 and 30, but a wide range in age of onset has been reported. Signs and symptoms may include loss of coordination of the hands, arms, and legs; impaired balance when walking; and slurred speech (dysarthria). SCA5 is caused by mutations in the SPTBN2 gene and is inherited in an autosomal dominant manner.

• ataxia (loss of coordination) of the hands, arms, legs, and gait
• slurred speech (dysarthria) - usually not severe and doesn't interfere with spoken communication
• ocular (eye) problems such as nystagmus

All known affected individuals have remained ambulatory despite having the condition for several decades. Non-cerebellar symptoms occur rarely but have included facial myokymia (spontaneous, fine muscle contractions); limited lateral gaze; tremor; writer's cramp; brisk reflexes; and impaired vibration.

Most labs that test for hereditary ataxias have a panel of tests that include testing for the forms that are most common and are known to be associated with specific genes and mutations. These forms may include SCA1, SCA2, SCA3, SCA6, SCA7, SCA10, SCA12, SCA14, and SCA17 (these are all associated with a specific type of mutation called a repeat expansion). Many labs offer them as groups in a step-wise fashion based on how commonly they occur. Testing can also be done for other autosomal dominant forms that are not associated with repeat expansions, including SCA5. If a specific type of SCA is already known to occur in a family member based on genetic testing, a person can have testing only for that specific type of SCA.

It is important to note that genetic testing may not always give a clear diagnosis, because genetic testing is not yet available for all hereditary ataxias. If a person who clearly has a hereditary ataxia has a normal genetic test result, they might have a type of SCA for which testing is not available.

People who have questions about a diagnosis of SCA and genetic testing for themselves or family members should speak with a neurologist and/or a genetics professional.

There is no known cure for spinocerebellar ataxia (SCA). The best treatment options for SCA vary by type and often depend on the signs and symptoms present in each person. The most common symptom of SCA is ataxia (a condition in which coordination and balance are affected). Physical therapy can help strengthen muscles, while special devices (e.g., cane, crutches, walker, or wheelchair) can assist in mobility and other activities of daily life. Many people with SCA have other symptoms in addition to the ataxia such as tremors, stiffness, muscle spasms, and sleep disorders; medications or other therapies may be suggested for some of these symptoms. One report described some improvement in the symptoms with zolpidem 10 mg in four out of five family members with SCA type 2, and a trial of 20 patients with SCA3 found that varenicline led to improvement in some, but not all of the symptoms.