Bio exam hd/Hailey Russell


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Huntington's disease

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Bio exam hd/Hailey Russell

  1. 1. Project by Hailey Russell
  2. 2. What is Huntington’s Disease (HD)? <ul><li>A point mutation that is autosomal dominant </li></ul><ul><li>Caused by a genetic defect on chromosome 4 </li></ul><ul><li>This defect causes a part of DNA, a CAG repeat, to occur many more times than is needed </li></ul><ul><li>Normally it is repeated 10-35 times, but in people with HD, it is repeated 36-120 times </li></ul><ul><li>As the gene is passed through generations, the number of CAG repeats get larger and larger </li></ul>
  3. 3. How is it inherited? <ul><li>Because the affected allele is dominant, only one parent has to be homozygous dominant or heterozygous to possibly give the child HD </li></ul><ul><li>If the parent is homozygous recessive, the parent neither has nor can give the child the disease </li></ul><ul><li>Since only 1 allele is passed, the child has a 50% chance of inheriting the affected allele from the diseased parent </li></ul><ul><li>2 diseased parents: 75% chance of child receiving allele (50% dominant disease, 25% double dominant) </li></ul>
  4. 4. HD Pedigree
  5. 5. Are There Other Ways of Getting HD? <ul><li>3% of HD cases have been sporadic </li></ul><ul><li>These instances can occur when a child has HD even though there is no other family history of the disease </li></ul><ul><li>They are caused by a new genetic mutation </li></ul><ul><ul><li>Origin of mutation is always paternal </li></ul></ul><ul><ul><li>This is an alteration in a HD gene that occurs during sperm development </li></ul></ul>
  6. 6. What are the Symptoms? <ul><li>Movement Symptoms </li></ul><ul><ul><li>Chorea (involuntary, rapid, ceaseless movement) </li></ul></ul><ul><ul><ul><li>Can become more intense when the person is anxious or disturbed </li></ul></ul></ul><ul><ul><li>Clumsiness </li></ul></ul><ul><ul><li>Jaw clenching </li></ul></ul><ul><ul><li>Loss of coordination/balance </li></ul></ul><ul><ul><li>Slurred speech </li></ul></ul><ul><ul><li>Difficulty swallowing/eating </li></ul></ul><ul><ul><li>Uncontrolled continual muscular contractions </li></ul></ul><ul><ul><li>Difficulty walking/stumbling/falling </li></ul></ul>
  7. 7. <ul><li>Cognitive Symptoms </li></ul><ul><ul><li>Overtime dementia develops </li></ul></ul><ul><ul><li>Ability to concentrate becomes more difficult </li></ul></ul><ul><ul><li>Person may have trouble driving, keeping track of thins, answering questions, and making decisions </li></ul></ul><ul><ul><li>Can possibly lose ability to recognize familiar objects </li></ul></ul>
  8. 8. <ul><li>Psychiatric Symptoms </li></ul><ul><ul><li>Depression </li></ul></ul><ul><ul><ul><li>Most common and develops early in course of disease </li></ul></ul></ul><ul><ul><ul><li>Signs include: hostility/irritability, inability to take pleasure in life, lack of energy </li></ul></ul></ul><ul><ul><li>Delusions </li></ul></ul><ul><ul><li>Hallucinations </li></ul></ul><ul><ul><li>Inappropriate behavior </li></ul></ul><ul><ul><ul><li>i.e.: unprovoked aggression </li></ul></ul></ul><ul><ul><li>Paranoia </li></ul></ul><ul><ul><li>Bipolar disorder </li></ul></ul>
  9. 9. How Does HD Affect Individuals? <ul><li>Usually signs of disease are revealed during middle age (between 30 and 45) </li></ul><ul><li>When the signs of the disease appear may vary </li></ul><ul><li>Symptoms progressively get worse and worse </li></ul><ul><li>The earlier the symptoms appear, the faster the disease progresses </li></ul><ul><li>Usually die within 15 to 20 years </li></ul><ul><ul><li>Cause is often because of infection, but cases of suicide are also common </li></ul></ul>
  10. 10. How Many Affected Individuals are There? <ul><li>Worldwide, there are about 5-10 cases per 100,000 people </li></ul><ul><li>Around 30,000 people in North America have the disease </li></ul><ul><li>Another 150,000 people in North America are considered “at risk” for inheriting the illness because they have (or had) a parent with HD </li></ul>
  11. 11. Who is More Likely to Get HD? <ul><li>The disease affects women and men equally </li></ul><ul><li>All ethnic groups can be affected </li></ul><ul><li>Rate of occurrence is higher in Western European descent though, averaging around 70 per 1 million people </li></ul><ul><li>In people with African or Asian decent, the rate is 1 in a million people </li></ul>
  12. 12. What is the Incidence of Carriers? <ul><li>0% </li></ul><ul><li>HD and other autosomal dominant diseases do not have carriers </li></ul><ul><li>If a child receives the diseased allele, the child is automatically infected with HD </li></ul>
  13. 13. Are There Treatments? <ul><li>No cures or ways to stop the disease from getting worse are known </li></ul><ul><li>The goal of the treatments is to slow the course of the HD and help the affected individual to function for as long and comfortably as possible </li></ul><ul><li>Dopamine blockers : help reduce abnormal behaviors </li></ul><ul><li>Tetrabenazine/amantadine : try to control extra movements </li></ul>
  14. 14. Is There Hope? <ul><li>Huntington’s Disease Society of America </li></ul><ul><ul><li>Organization dedicated to improving the lives of people with HD </li></ul></ul><ul><ul><li>Promote and support research of HD </li></ul></ul><ul><ul><li>Help people and families cope with the struggles brought by the disease </li></ul></ul><ul><ul><li>Educate the public and heath professionals about HD </li></ul></ul>
  15. 15. Bibliography <ul><li>eMedTV. (November 30, 2006). Inheriting Huntington’s Disease . Retrieved from's-disease/inheriting-huntington's-disease.html. May 19, 2011 .   </li></ul><ul><li> (May 19, 2011). Signs & Symptoms of Huntington’s Disease, Complications . Retrieved from May 13 , 2011. </li></ul><ul><li>Huntington Study Group. (2010). A Huntington’s Disease Overview . Retrieved from May 20 , 2011. </li></ul>
  16. 16. <ul><li>Huntington’s Disease Society of America. (2008). HDSA Mission . May 21 , 2011. </li></ul><ul><li>  </li></ul><ul><li>MedlinePlus. (May 2, 2011). Huntington’s Disease . Retrieved from May 12 , 2011. </li></ul><ul><li>New York Times. (May 22, 2007). Huntington’s Disease . Retrieved from May 18 , 2011. </li></ul><ul><li>  </li></ul><ul><li>Wrong Diagnosis. (April 29, 2011). Inheritance and Genetics of Huntington’s Disease . Retrieved from May 20 , 2011. </li></ul>