I am 1 in 150,000

Spinocerebellar ataxia 3 

Spinocerebellar ataxia (SCA) is a progressive, degenerative,^[1] genetic disease with multiple types, each of which could be considered a disease in its own right. An estimated 150,000 people in the United States are diagnosed with Ataxia, SCA's are the largest group of this hereditary, progressive, degenerative and often fatal neurodegenerative disorders. There is no known effective treatment or cure. Ataxia can affect anyone of any age. It is caused by either a recessive or dominant gene. Many times people are not aware that they carry the ataxia gene until they have children who begin to show signs of having the disorder.^[2]

 

SCA3[6] (MJD) (ATXN3)

4th decade (10–70)

10 years (1–20)

Also called Machado-Joseph disease (MJD)[7] Gaze-evoked nystagmus (a rapid, involuntary, oscillatory motion of the eyeball) upper motor neuron slow saccades

Azores (Portugal)

CAG repeat, 14q

 

^{'Machado–Joseph disease' (MJD) or Spinocerebellar ataxia type 3 (SCA3) is a rare autosomal, dominantly inherited neurodegenerative disease that causes progressive cerebellar ataxia,[1] which results in a lack of muscle control and coordination of the upper and lower extremities.[2] The symptoms are caused by a genetic mutation that results in an expansion of abnormal "CAG" trinucleotide repeats in the ATXN3 gene [1] that results in degeneration of cells in the hindbrain.[2] Some symptoms, such as clumsiness and rigidity, make MJD commonly mistaken for drunkenness and/or Parkinson's disease.}

 

The disease is caused by a mutation in the ATXN3 gene, which is located on chromosome 14q. The gene contains lengthy irregular repetitions of the code "CAG", producing a mutated protein called ataxin-3. (Normally, the number of copies is between 13 and 41.)^[7] MJD is an autosomal dominant disease, meaning that if either parent gives the defective gene to a child, the child will show symptoms of the disease. Therefore, if one parent suffers from this disease and the other parent does not, then if they decide to have children, there will be a 50% chance of their child inheriting the disease.^[2]
The pons (a structure located on the brain stem) is one of the areas affected by MJD. The striatum (a brain area connected to balance and movement) is also affected by this disease, which could explain both of the main motor problems cause by MJD: the tightening and twisting of the limb and the abrupt, irregular movements.^[8]
In affected cells, this protein builds up and assembles intranuclear inclusion bodies. These insoluble aggregates are hypothesized to interfere with the normal activity of the nucleus and induce the cell to degenerate and die.^{[citation needed]}

The hereditary ataxias are categorized by mode of inheritance and causative gene or chromosomal locus. The hereditary ataxias can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner.

• Many 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." (Spinocerebellar degeneration is a rare inherited neurological disorder of the central nervous system characterized 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.)

• 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 (AOA), spastic ataxia. Disorder subdivisions: Friedreich's ataxia, Spinocerebellar ataxia, Ataxia telangiectasia, Vasomotor ataxia, Vestibulocerebellar, Ataxiadynamia, Ataxiophemia, Olivopontocerebellar atrophy, and Charcot-Marie-Tooth disease.

• There have been reported cases where a polyglutamine expansion may lengthen when passed down, which often can result in an earlier age-of-onset and a more severe disease phenotype for individuals who inherit the disease allele. This falls under the category of genetic anticipation.

MJD can be diagnosed by recognizing the symptoms of the disease and by taking a family history. Physicians ask patients questions about the kind of symptoms relatives with the disease had, the progression and harshness of symptoms, and the ages of onset in family members.
Presymptomatic diagnosis of MJD can be made with a genetic test.^[9] The direct detection of the generic mutation responsible for MJD has been available since 1995.^[10] Genetic testing looks at the number of CAG repeats within the coding region of the MJD/ATXN3 gene on chromosome 14. The test will show positive for MJD if this region contains 61-87 repeats, as opposed to the 12-44 repeats found in healthy individuals. A limitation to this test is that if the number of CAG repeats in an individual being tested falls between the healthy and pathogenic ranges (45-60 repeats), then the test cannot predict whether an individual will have MJD symptoms.<sup>[9]



 So this is me and my fate! This is what my father, grandfather and grandmother died from! 









http://en.wikipedia.org/wiki/Spinocerebellar_ataxia
 http://en.wikipedia.org/wiki/Machado-Joseph_disease</sup>