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By: Catherine Peters What is Huntington’s or Huntington's Chorea? Huntington’s disease is an incurable hereditary brain disorder in which nerve cells become damaged, causing various parts of the brain to deteriorate. The disease affects movement, behavior and the affected individuals' abilities to walk, think, reason and talk. These functions are gradually eroded to such a point that they eventually become entirely reliant on other people for their care. People usually start to show symptoms at 30-40’s of age. There is no effective treatment. The brain of a Huntington’s Patient As you can see, the brain on the HD patient has deteriorated. HISTORY OF HUNTINGTON’S Before the 19th century, some HD sufferers were thought to be possessed by spirits or persecuted as witches, and were shunned or exiled by society. The first thorough description of the disease was by George Huntington, who openly accommodated those with HD and studied them, in 1872. Examining the combined medical history of several generations of a family exhibiting similar symptoms, he realized their conditions must be linked. Huntington's Disease was mentioned in medical literature for the first time in the 1840s. Three young doctors writing in three different countries, England, Norway and the United States, described people afflicted with involuntary movements and mental disturbances inherited from a similarly affected parent. In 1872, Dr. George Huntington wrote a landmark paper accurately describing the disease and stressing its hereditary nature. He was the third generation in a family medical practice in Long Island, New York. From the doctors' combined experience of a family with the same symptoms in each generation, he documented his observations and the disease received his name in honor of his work. (Continued) Huntington’s disease is hereditary. The faulty gene that causes Huntington's disease is found on chromosome number 4. A normal copy of the gene produces huntingtin, a protein. The faulty gene is larger than it should be and produces a larger form of huntingtin. Some of our brain cells are sensitive to the larger form of huntingtin - it undermines their function and eventually destroys them. (Continued) A person with the Huntington's gene has one good copy of the gene and one faulty copy of the gene. His/her child will inherit either the good copy or the faulty one. The child who inherits the good copy will not develop Huntington's disease, while the child who inherits the faulty copy will. The child has a 50% chance of inheriting the faulty gene. If the child inherits the faulty gene, each of his/her children will have a 50% chance of inheriting the faulty gene. Huntington's disease is inherited in an autosomal dominant pattern. This means that everyone who inherits the faulty gene will eventually get the disease.So this disease can be passed on to future generations. PHENOTYPIC (PHYSICAL) EFFECTS OF HD Head shifting to look around instead of just moving the eyes. Speech impairment Uncontrolled movements Sudden jerks Trembling inability to regulate the speed or force of movements sustained abnormal postures What type of mutation is HD? HD is caused by a mutation in a gene on chromosome 4. So it is a gene mutation. A gene mutation falls into the categories of mutations by: Frameshift mutations or base pair substitutions. Chromosomal mutations are mutations that result in the whole addition, loss or inversion of the chromosome. Huntington's disease is caused by a frameshift mutation due to the addition of extra nucleotides. The mutant huntingtin -gene that codes for huntington's disease is located on chromosome 4 which contains more than 36 glutamine amino acids which should normally only contain less than 36. Healthy gene Vs. HD gene Normal sequence Abnormal expanded sequence • The abnormal expanded sequence is called a trinucleotide repeat. During pregnancy a woman can find out if her baby will have the disease with two tests: taking a sample of fluid from around the fetus (amniocentesis), or by taking a sample of fetal cells from the placenta (chorionic villus sampling (CVS)). How is HD treated? There is no cure for Huntington’s disease, Treatments do not slow the progression of the disease, but they can help make the patient more comfortable. Medications ease feelings of depression and anxiety; others control involuntary movements. Unfortunately, after the symptoms start, the individual only has about 8-10 years to live. 3-7 people out of 100,000 have HD in Europe. 1 person out of 30,000 in America 150,000 other people are at risk HD is less common in Asians and AfricanAmericans. Extra: Video BIBLIOGRAPHY "Huntington's Disease History." News Medical. N.p., n.d. Web. 18 Nov. 2012. <http://www.medicalnewstoday.com/articles/159552.php>. Huntington's Disease History What Is The History Of Huntington's Disease (HD)?" Huntingtons. N.p., n.d. Web. 18 Nov. 2012. <http://www.huntingtonsnsw.org.au/information/hdfacts/history>. History of Huntington's Disease "What Is Huntington's Disease? What Causes Huntington's Disease?" Medical News Today. N.p., n.d. Web. 18 Nov. 2012. <http://www.medicalnewstoday.com/articles/159552.php>. Information on Huntington's "Huntington's Disease." Learn Genetics. N.p., n.d. Web. 18 Nov. 2012. <http://learn.genetics.utah.edu/content/disorders/whataregd/hunt/>. Info on HD