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=HUNTINGTON'S DISEASE =

Huntington's Disease (HD) is a neurodegenerative disorder. This means that the nerve cells in the brain are being damaged and wasting away. //How it's Caused// Huntington's Disease is caused by a sequence of DNA on chromoseome 4 that is slightly altered. This makes it an autosomal disorder because it is not on one of the sex cromosomes. The autosomes are chromosomes 1-22 and the sex chromosome is number 23. A person with Huntingtons Disease has the right amount of chromosomes, but has the wrong DNA sequence on the bottom of chromosome 4. Either copy of a gene called Huntingtin is mutated. The gene repeats the nucleotide sequence CAG.

//Characteristics and Symptoms//
A person with Huntington's Disease normally will not experience symptoms untill later in life. Only 6% of cases start before age 21. This disease usually starts at age 35-44. Huntington's Disease causes things like a decrease in mental ability, involuntary jerking or withering movements, loss of balance and coordination, mood swings, and depression. Huntington's disease can lead to more serious things as well. Often people with Huntington's will develop heart disease, dementia, and pneumonia. // Statistics // There are about 30,000 people in the United States that have Huntington's Disease, however, the odds of getting it are about 1 in 15,000. 1-3% of those people previously had no family history of the disease. The average life expectancy for someone with HD is about 15 years. If a juvenile has been diagnoased, they will die in fewer than 15 years. In certain populations, HD is more common. For instance, you have a better chance of getting this disease if you are of western European decent. HD is also very common in the Lake Maracaibo region of Venezuela. If a parent is affected, there is a 50% chance that the child will get it. If both parents are affected, there is a 100% chance that the child will get it. // Outside Factors // Currently, we aren't sure what causes the mutation on the 4th chromosome to take place, other than it being passed down. At this time we don't know what environmental factors lead to the development of HD. Some people think that a warmer climate may increase your chances of developing HD, but we won't know for sure until more research is done.

// Interesting Facts //
HD is sometimes called "Woody Guthrie's disease" because of the American folk singer who died of it. There is no cure for HD, but there are medications to lessen the symptoms. There have been attempts at stem-cell therepy to cure HD, but nothing so far has worked.



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World of Genetics Volume 1 by K. Lee Lerner and Brenda Wilmoth Lerner, Gale Group Staff

Magill's Medical Guide 4th Revised Edition Vol. 3