Spinocerebellar ataxia

 ICD9        = 334|

}} Image:Brain-cerebellum.png Spinocerebellar ataxia (SCA) is a genetic diseasewith multiple types, each of which could be considered a disease in its own right. As with other forms of ataxia, SCA results in unsteady and clumsy motion of the body due to a failure of the fine coordination of musclemovements, along with other symptoms.

It can be easily misdiagnosed as another neurologicalcondition, such as multiple sclerosis(MS). There is no known cure for this degenerative condition, which lasts for the remainder of the sufferer's life. Treatments are generally limited to softening symptoms, not the disease itself. The condition is irreversible. A person with this disease will usually end up needing to use a wheelchair, and eventually they will need assistance to perform daily tasks. The symptoms of the condition vary with the specific type (there are several), and with the individual patient. Generally, a sufferer retains full mental capacity while they progressively lose physical control over their body until their death.

One means of identifying the disease is with an MRIto view the brain. Once the disease has progressed sufficiently, the cerebellum(a part of the brain) can be seen to have visibly shrunk. The most precise means of identifying SCA, including the specific type, is through DNAanalysis. Some, but far from all, types of SCA may be inherited, so a DNA test may be done on the children of a sufferer, to see if they are at risk of developing the condition.

SCA is related to olivopontocerebellar atrophy(OPCA); SCA types 1, 2, and 7 are also types of OPCA. However, not all types of OPCA are types of SCA, and vice versa. This overlapping classification system is both confusing and controversial to some in this field.

Types

The following is a list of some, not all, types of Spinocerebellar ataxia. The first ataxia genewas identified in 1993for a dominantly inherited type. It was called ?Spinocerebellar ataxia type 1" (SCA1). Subsequently, as additional dominant genes were found they were called SCA2, SCA3, etc. Usually, the "type" number of "SCA" refers to the order in which the gene was found. At this time, there are at least 22 different gene mutations which have been found (not all listed).

Identifying the different types of SCA now requires knowledge of the normal genetic code, and faults in this code, which are contained in a person's DNA(Deoxyribonucleic acid). The "CAG" mentioned below is one of many three-letter sequences that makes up the genetic code, this specific one coding the aminoacid glutamine. Thus, those ataxias with poly CAG expansions, along with several other neurodegenerative diseases resulting from a poly CAG expansion, are referred to as polyglutamine diseases.

Notes

Both onset of initial symptoms and duration of disease can be subject to variation. If the disease is caused by a polyglutamine trinucleotide repeat CAG expansion, a longer expansion will lead to an earlier onset and a more radical progression of clinical symptoms, resulting in earlier death.

Technical description

Spinocerebellar ataxia is one of a group of genetic disorderscharacterized by slowly progressive incoordination of gaitand often associated with poor coordination of hands, speech, and eye movements. Frequently, atrophyof the cerebellumoccurs.

The hereditaryataxias are categorized by mode of inheritance and causative geneor chromosomallocus. The hereditary ataxias can be inherited in an autosomal dominant, autosomal recessive(such as Friedreich's ataxiaand ataxia-telangiectasia), or X-linked manner.

• Numerous types of autosomal dominant cerebellar ataxias are now known for which specific genetic information is available. Synonyms for autosomal dominant cerebellar ataxias (ADCA) used prior to the current understanding of the molecular genetics were Marie's ataxia, inherited olivopontocerebellar atrophy, cerebello-olivary atrophy, or the more generic term "spinocerebellar degeneration."

• There are five typical autosomal recessive disorders in which ataxia is a prominent feature: Friedreich ataxia, ataxia-telangiectasia, ataxia with vitamin E deficiency, ataxia with oculomotor apraxia, spastic ataxia. Disorder Subdivisions: Friedreich's ataxia, Marie's ataxia, Ataxia telangiectasia, Vasomotor ataxia, Vestibulocerebellar, Ataxiadynamia, Ataxiophemia, Olivopontocerebellar atrophy, and Charcot-Marie-Tooth disease.

Spinocerebellar degeneration is a rare inherited neurological disorder of the central nervous systemcharacterized by the slow degeneration of certain areas of the brain. There are three forms of spinocerebellar degeneration: Types 1, 2, 3. Symptoms begin during adulthood.

External links

• Genes and Disease- Gives a concise description of SCA, along with a picture of shrunken degenerated cerebellum.
• Rehab Network web site- Detailed description of SCA.
• Cerebellar Degenerations
• Hereditary ataxia overview
• Spinocerebellar ataxia type 1, 2, 3, 6, 7, 8, 10, 12, 14, 17
• Machado-Joseph Disease(MJD) - SCA type 3 (SCA3) can also be called MJD. This page is provided by the National Institute of Neurological Disorders and Stroke.
• DRPLA- Dentatorubropallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterised by myoclonus, epilepsy, cerebellar ataxia, choreoathetosis and dementia.de:Spinozerebelläre Ataxie

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Spinocerebellar+ataxia Wikipedia article Spinocerebellar ataxia.