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SPRING 2023 InTouch | 17 RFC1 on chromosome 4 is the cause of this disorder. Inheritance The mode of inheritance for the majority of SCA subtypes is autosomal dominant, meaning an individual needs only to inherit the causative gene variant from one parent to be affected. Friedreich Ataxia, some less common SCA subtypes, and CANVAS are inherited in an autosomal recessive fashion. In these cases, affected individuals inherit one gene variant from each parent. Diagnosis A diagnosis of hereditary ataxia is often suspected when certain signs and symptoms, such as an ataxic gait or uncoordinated limb movements, are present. Genetic testing is the best way to confirm the disorders for which the causative gene has been identified (i.e., FA, the more common SCA subtypes, and CANVAS). Genetic testing can also predict if an individual is likely to go on and develop the disorder. Carrier testing for at-risk relatives and prenatal testing are possible if the disease- causing mutations in the family are known. This is best done under the guidance of a genetic counsellor. In many individuals, the specific genetic cause may remain unknown even after genetic testing is performed. In these cases, brain imaging studies such as computed tomography (CT scan) and/or magnetic resonance imaging (MRI scan) may be helpful in establishing a diagnosis. Other studies, such as nerve conduction studies and electromyography, may also be helpful. SPINOCEREBELLAR ATAXIA (SCA) Treatment There is no known cure for any type of hereditary ataxia. The best treatment options will depend on the signs and symptoms present in each person. Physical therapy can help strengthen muscles, while mobility aids (e.g., walking stick, walker, or wheelchair) can assist in mobility and other activities of daily life. Many people will 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. Prognosis The long-term outlook (prognosis) for people with SCA, FA, or CANVAS varies. Most available information on the prognosis of SCA is based on the four most common subtypes: SCA1, SCA2, SCA3, and SCA6. People affected by one of these types of SCA usually require a wheelchair around 10-15 years after the onset of symptoms and many will eventually need assistance to perform daily tasks. The lifespan of individuals with FA can be shortened due to The above illustration shows the common symptoms of Ataxia. Continued over ...