Huntington's disease is an autosomal dominant disorder, which is found on the # 4 chromosome. George Huntington discovered it in 1872. It mainly has an effect on the nervous system. There are around 210,000 bases between D4S180 and D4S127. The disease itself is found in 2% of people in their childhood, and in 5% of the people they were older then 60. (Miller p 16) In the majority of the affected people the disease is detected between the ages of 35-45. In males the disease begins around the time of their childhood. However, in females it begins later in life. This severe symptom has a tendency for the condition to worsen as it is passed on from generation to generation. Huntington's disease is paternally inherited and new mutations are rare (about 1%). (Encarta Encyclopedia)
The basic biochemical defect has not yet been discovered. There is a high amount of quinolinic acid, a neurotoxin normally present in the brain. Quinolinic acid may be killing receptors. These receptors are known targets of quinolinic acid. The gene encodes an amino acid protein called huntington. The protein does not show any resemblance to other proteins. Scientists are also finding it difficult to detect differences in people's gene movement who are and are not affected by the disease. The enzyme huntington binds to glyceraldehydes-3-phosphate-dehydrogenase (GAPDH), a important enzyme in glycolysis. The cells now have inefficient glucose to the cells, which in the overall process causes the cells to die. ( Science News p268 )
Symptoms that may be expressed include memory loss, mood swings, slurred speech, depression, and death usually from heart disease or pneumonia. There can also be steady downfall of the person mental health. This also can destroy two small regions of the brain (the putamen and the caudate nucleus) that help control movement.
If the disease is of the homozygous variety in a person it occurs in 1 in every 10,000 people. If the disease...