Spinocerebellar Ataxia (SCA) is the name given to a group of hereditary conditions where the cerebellum (a part of the brain that controls co-ordination) begins to atrophy and as a result, the affected person finds that their ability to use the affected parts of the body becomes progressively more difficult and less exact. As a hereditary condition, its incidence is controlled by one of a selection of mutated genes (there are currently some 60 types of SCA that have been identified), but since there is no single test to tell which type of SCA a person has, many of the identifications have only been made by autopsy and living patients therefore are very rarely able to find out which type of SCA they have. When people use the name Spinocerebellar Ataxia the definition they are applying to it is usually any one or all of these conditions.
When Was It Identified?
The first gene mutation causing SCA was identified in 1992 and named “Spinocerebellar Ataxia Type 1” (SCA1). As further genes were identified they were given numerically sequential names (SCA2, SCA3, etc) and so far there have been at least 29 gene mutations found. In 2008, a test was identified for a dozen or so forms of Ataxia, including three forms of SCA (SCA1, 3 and 8), but otherwise the diagnosis by a neurologist is usually just “Spinocerebellar Ataxia” and even that requires a physical exam, MRI scans of both spine and brain, a spinal tap and knowledge of the family history in order to be certain. Different types of SCA may begin to appear at different times; many are adult onset, around the fourth decade of life, but some are early onset, beginning to affect children at under ten years of age.
What Does It Do?
The cerebellum controls the ability to co-ordinate the various parts of the body, and a person with SCA finds that they have a progressive reduction in this co-ordination, depending on which area within the cerebellum is most affected. Usually it is first noticed with the legs, as an increasing difficulty in walking, but often it begins to affect fine co-ordination of other parts of the body and the person becomes gradually more clumsy and unsteady in all physical movements. SCA does not generally affect mental capacity at all, but other symptoms such as tremor, depression, stiffness and sleep disorders are known to occur.
What Can Be Done?
A few treatments are available for SCA patients, but they concentrate on alleviating the symptoms rather than the condition itself. Medication can be used to alleviate some of the additional symptoms mentioned, and some good results have been obtained in rehabilitating impaired patients with physical therapy since, basically, he or she needs to re-learn how to use the various muscles. Accuracy of movement can be assisted with canes, walkers and wheelchairs and, depending on the level and location of impairment, other devices are available to help with self care, writing, feeding and other ‘activities of daily living’ (ADLs).
Unfortunately, there is so far no cure for these progressive and irreversible conditions.