Is it possible to get huntingtons disease even if neither parent had it? at least, neither of my parents showed symptoms, but they both died before age 50. my doctor wants me to get tested based on my symptoms and the fact that i remember my grandfather
2 doctor answers • 6 doctors weighed in
Neurology 29 years experience
Doctors : Doctors who recommend genetic tests, such as a test for huntington's disease, should not do so without providing thorough counseling, including providing information and answering all questions about the reason for ordering the test, the reliability of the test, and the consequences of both positive and negative test results. If they are unable to provide this counseling, they should arrange for referral to a geneticist.
Huntington's disease is a complicated neurodegenerative disorder that can cause involuntary writhing, dance-like movements of the limbs, other abnormal movements, personality changes and psychiatric symptoms, heart disease and other problems. It is an uncommon condition (about 5-10 cases per 100000 people).
Huntington's disease is caused by a mutation in the huntingtin gene. Inside this gene is a stretch of dna that consists of repeating sequences the genetic code letters, or nucelotides, c, a, and g. These three nucleotides can be repeated (cagcagcag...) dozens of times. The number of "trinucleotide repeats" seems to determine if and when the disease will make itself known. People with less than 28 repeats are normal. People with 28 to 35 repeats are "intermediate". People with 35 to 40 repeats may or may not develop huntington's disease. People with more than 40 repeats will be affected, and the higher the number of repeats, the earlier the disease starts.
Trinucleotide repeat diseases like huntington's disease (there are others), are characterized by a property called "anticipation." anticipation means that children of people with huntington's often develop the disease at an earlier age than their parents did. This was first noticed even before anything was known about trinucleotide repeats. After the repeats were discovered, it was found that children had more repeats than their parents. The number of repeats tends to increase more if the father carried the abnormal gene.
So, unfortunately, it is possible for a child of parents who never showed any signs of huntington's disease to develop the disease. This is particularly true if the parents died at an early age, before signs of the disease might be noticed.
5.3k viewsReviewed >2 years ago
Infectious Disease 23 years experience
Huntington's disease: Huntington's is a debilitating neurological disease with no cure. However 'knowing' if one may develop this disease later in life from a genetic test brings up philosophical questions. Most cases are 'traceable' thru the family tree, although on rare occasion it may arise by itself. If your folks died 'young', looking farther back into the family history may help. I heed an MD's suspicions.
4k viewsAnswered >2 years ago
Last updated Apr 1, 2019
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