This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Spinocerebellar ataxia 13 (SCA13) is a rare sub-type of spinocerebellar ataxias (SCA), a group of neurological diseases that causes degeneration of the brain and spinal cord. The age when symptoms begin and the type and severity of symptoms of SCA13 can be different from person to person even in the same family. In almost every case, the disease progresses very slowly and does not affect a person’s life span. Symptoms most commonly begin in early childhood or later in midlife, but can range from infancy to 60. The childhood forms is often least progressive, but may also include mild to moderate learning problems, taking longer to learn to crawl, walk, or run (delayed development of motor skills), and seizures. The main symptoms of SCA13 include difficulties coordinating movements (ataxia), especially walking; abnormal eye movements (nystagmus); mild to moderate intellectual disability; and involuntary muscle jerks or twitches (myoclonic jerks). Other symptoms may include speech difficulty (dysarthria), difficulty eating (dysphagia), slowness of movements (bradykinesia), mild bladder problems, stiff and brisk deep tendon reflexes, and loss of the sense of vibration.
SCA13 is caused by changes or mutations in the KCNC3 gene and it is inherited in an autosomal dominant manner. Since the symptoms of SCA13 can be similar to other types of SCA, genetic testing is used to confirm the diagnosis. In addition, unlike most of the other SCA’s, a brain MRI will find loss of brain cells (neurons) in the part of the brain that helps control movement (cerebellum), but no noticeable loss of brain cells in the brain stem or the part of the brain important to higher levels of thinking (cerebral cortex). Treatment may include anti-seizure medications, special assistance in school, speech therapy and communication devices, and/or, later in the disease, aids to help with walking such as a canes and walkers. Normal activity and exercise are recommended. Maintaining a healthy weight may help keep a person walking without assistance longer. The use of alcohol may increase the severity of the uncoordinated movements (ataxia).
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