GENETICS Huntington's Disease MUST HAVE BIOLOGY BACKGROUND Essay

GENETICS Huntington's Disease MUST HAVE BIOLOGY BACKGROUND - Essay Example But as this molecular cartography advances, clinical medicine is turning topsy-turvy in its wake. Huntingtons disease is an autosomal dominant neurodegenerative disease. Appearing usually in the third or fourth decade of life, it can begin in early childhood or old age. A triad of disturbances is pathognomonic: uncontrolled involuntary movements usually including chorea, intellectual decline, and psychiatric disturbance, mostly depression. The disease progresses for twenty years toward an inevitably fatal outcome, and therapy is palliative at best. Families, scientists, and clinicians involved with research on or treatment of Huntingtons disease have been .aware that their development of counseling and diagnostic program using DNA markers could be as precedent-setting as the discovery of the marker itself. They have been trying to act with caution and sensitivity, at the same time making the test available. The Tests offered. Presymptomatic and prenatal testing can now be carried out with a number of different markers to enable risks to be changed from 50 percent to 96 percent or higher of being positive or negative for the gene of Huntingtons disease. Even though there has been some uncertainty as to the exact location of the gene within the most telomeric band on chromosome 4, there are sufficient markers to alter a persons risk significantly if a family is genetically informative. Initially, less than half of all families listed on the National Huntingtons Disease Roster at Indiana University had such an appropriate structure. Owing to the increased informativeness of recently developed markers, recent estimates suggest that up to 75 percent of individuals coming for testing will be found to have genetically informative families. Prenatal Diagnosis. Two types of prenatal diagnostic tests are available: 1) a non-disclosing prenatal or "exclusion test," and 2) a fully disclosing diagnostic test. In a