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  • -It is a genetic disease -Gets its name from the physician, George Huntington, who first described the illness in 1872 -However, there is a form know as Juvenile HD, develops before the age of 20, progresses rapidly, and produces muscle rigidity in which the patient moves little, if at all (akinesia).
  • -The age of onset, the degree and type of clinical symptoms, as well as rate of progression varies from patient to patient, and can sometime even vary greatly within one family. -Important to note that these symptoms are not always identified with someone having HD, so sometimes a person is not diagnosed with the disease until later stages of the disease have taken place
  • As stated earlier, these symptoms do not occur until later on in life (usually between the ages of 35-50). Often times, in the later stages of the disease, full time care is needed for the person with HD. Often times, people with HD die from something other than HD such as pneumonia or choking on foods (because one cannot force his/her muscles to swallow the food).
  • HD targets the basal ganglia (structures deep within the brain that have many important functions, including coordinating movement). Within the basal ganglia, HD especially targets neurons of the striatum , particularly those in the caudate nuclei and the pallidum . Also affected is the brain's outer surface, or cortex , which controls thought, perception, and memory.
  • -Autosomal Dominant- Carried on one of the twenty two autosome (non-sex) genes. It was discovered in 1993 that it was carried on autosome pair #4 -The gene encodes a protein called Huntingtin ,which is necessary for striatal tissue survival. The normal allele for HD promotes its development, but the mutant type blocks it, causing brain’s mass to degenerate -An affected parent passes either the HD gene, or the other working gene, to their off spring. There is a 50% (1 in 2) chance at each pregnancy that a child of an affected parent will receive the gene for Huntington disease. -It was only recently that many researchers have began to accept the possibility that HD can develop from a genetic mutation in families that never had the disease
  • -In Huntington disease, the DNA sequence, CAG (cytosine-adenine-guanine), Individuals with Huntington disease may have from 40 to over 100 repeated CAG segments . It is not known how this repeated sequence causes Huntington disease, but research to develop therapies to treat Huntington disease is ongoing. However, it has been determined that the number of CAG can determine the age in which the disease will manifest
  • -Huntington’s disease is not prevalent within any particular population. All races and ethnic groups, and both sexes are affected. -150,00 at risk who do not know it because the disease does not manifest itself till later in life -Because such a small percentage of the population have the disease, drug companies do not sponsor research for new drugs that help to alleviate the condition -There are a few social ramifications of the disease: -The suicide rate in HD patients is 12.7%, which as indicated by epidemiological and phenomenological evidence, is a result of emotional depression and affective mood disorder caused by the disease rather than a direct reaction to changes in life circumstances -Important to note, that unlike diseases such as Sickle Cell Anemia, there are currently no known adaptive possibilities and/or benefits of having the disease
  • -One such drug bromocriptine, was found to produce a significant reduction in the involuntary movements or chorea. -The purpose of this high calorie diet is to stop the rapid weight loss. -Speech therapy has proven very effective in helping with a victims communication and helping them learn to digest foods again. -No known cure, but since the discovery of the Huntington gene in 1993, much research has been carried out - Huntingtin is a protein which is necessary for striatal tissue survival. The normal allele for HD promotes its development, but the mutant type blocks it, causing less new brain cells to be developed -In animals (such as primates) HD models, behavioural signs analogous to HD can be improved by transplantation of embryonic striatal tissue into the degenerated striatum.  -Pre-symptomatic screening is possible because of the discovery of the mutant allele on chromosome 4, but is not recommended for minors
  • Presentation File

    1. 1. Huntington's Disease  Damon Jason Jakub Jedrkowiak
    2. 2. Introduction <ul><li>Huntington’s Disease (HD) is a progressive degenerative condition </li></ul><ul><li>Genetic defect </li></ul><ul><li>George Huntington-1872 </li></ul><ul><li>Causes brain nerve cells to waste away </li></ul><ul><li>Victim shows symptoms later in life </li></ul>
    3. 3. Early Symptoms of HD <ul><li>slight, uncontrollable muscular movements </li></ul><ul><li>stumbling and clumsiness </li></ul><ul><li>lack of concentration </li></ul><ul><li>short-term memory lapses </li></ul><ul><li>depression </li></ul><ul><li>changes of mood, sometimes including aggressive or antisocial behavior </li></ul>
    4. 4. How HD Progresses <ul><li>Change in one’s physical state </li></ul><ul><ul><ul><li>Involuntary movements </li></ul></ul></ul><ul><ul><ul><li>Slurred speech </li></ul></ul></ul><ul><ul><ul><li>Weight loss </li></ul></ul></ul><ul><li>Change in one’s emotional state </li></ul><ul><ul><ul><li>Mood swings </li></ul></ul></ul><ul><ul><ul><li>Depression </li></ul></ul></ul><ul><ul><ul><li>Easily frustrated </li></ul></ul></ul>
    5. 6. Genetics of HD <ul><li>Autosomal dominant condition </li></ul><ul><li>For an affected parent, 50% chance of transmission with each pregnancy </li></ul><ul><li>DNA sequence is CAG </li></ul><ul><li>Can be caused by genetic mutation </li></ul>
    6. 8. Incidence of HD <ul><li>Only one in 10,000 </li></ul><ul><li>30,000 known cases in the U.S </li></ul><ul><li>16% of all cases Juvenile HD </li></ul><ul><li>150,000 people (US) who are at risk </li></ul><ul><li>Death 10-20 years after initial symptoms </li></ul><ul><li>The suicide rate is 12.7% </li></ul><ul><li>No known adaptive benefits </li></ul>
    7. 9. Cures? <ul><li>Currently there is no known cure </li></ul><ul><li>Pharmaceutical drugs have been used to control the symptoms. </li></ul><ul><li>High calorie diet </li></ul><ul><li>Two potential cures: </li></ul><ul><ul><li>Inhibiting protein expression of mutant allele </li></ul></ul><ul><ul><li>Striatal transplantation </li></ul></ul>
    8. 10. References <ul><li>Collins, Debra. “Genetics of Huntington’s Disease.” Updated 15 Feb 1999. Retrieved April 2005 <http://www.kumc.edu/hospital/huntingtons/genetics.html>. </li></ul><ul><li>The Huntington’s Disease Association. Updated Apr. 2005. Retrieved Apr. 2005. < http:// www.hda.org.uk/charity/whatishd.html >. </li></ul><ul><li>Hosey, Alison. “ Huntington’s Disease: Pathogenesis and Treatment.” Trinity Student Medical Journal. Updated 2003. Retrieved Apr. 2005 < www.tcd.ie/tsmj / 2003/huntingt.htm > </li></ul><ul><li>“ Huntington's Disease: Hope Through Research.” National Institute of Neurological Disorders and Stroke. Updated 9 Feb 2005. Retrieved Apr. 2005 < http://www.ninds.nih.gov/disorders/huntington/detail_huntington.htm >. </li></ul><ul><li>“ Huntington’s Disease.” Neurology Channel. Updated May 2004. Retrieved Apr. 2005 <http://www.neurologychannel.com/huntingtons/>. </li></ul>

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