Why is huntington disease still around

One idea is that, similar to how full-length huntingtin containing many glutamines might gum up cells, the longer the polyglutamine chain of HTT exon 1 is, the more strongly the fragment can bind to other molecules. Other scientists blame the tendency of HTT exon 1 to aggregate with itself. In turn, such aggregations can disrupt a variety of cellular functions, leading inexorably to neurodegeneration. They also occur in all known diseases caused by expanded CAG repeats, including spinocerebellar ataxia.

More from Nature Outlooks. Wetzel and his collaborators have shown that polyglutamine chains acquire a much greater propensity to stick to each other and form aggregates when they reach 37 amino acids long. This observation provides a potential link between the disease-causing threshold of the CAG repeats and the biochemistry of huntingtin. But some of the antisense molecules being tested target a portion of HTT that is distant from exon 1, Disney says.

About this content. Huntington, G. Google Scholar. Gusella, J. Nature , — PubMed Article Google Scholar. Cell 72 , — Guo, Q. Mangiarini, L. Cell 87 , — Barbaro, B. Download references. Technology Feature 09 NOV Research Highlight 29 OCT Article 03 NOV News 29 OCT Article 06 OCT The larger the number of triplet repeats, generally speaking, the earlier in life one will develop HD.

Furthermore, when the gene is passed from father to child but not when passed from mother to child the gene may lengthen even more, resulting in an earlier age of onset for the disease. This phenomenon is known as anticipation. Genes for diseases can be either dominant or recessive. The gene for HD is dominant. On the other hand, if people with a parent suffering from HD do not inherit the mutant gene, they cannot pass it on to anyone else. It is important to understand that while people are born with the mutated gene for HD, in most cases they will not develop the symptoms until later in life.

Therefore someone can be without symptoms or presymptomatic for a number of years. In the past, there was no way to test for the abnormal gene, but now a blood test can determine whether or not an individual carries the gene for HD. This test can be used in cases of suspected HD, to confirm the diagnosis, or it can be used as a predictive test in individuals who are at risk for HD. People who are at risk may want to undergo predictive testing in order to put their minds at ease, to plan for their medical needs, or prior to having children.

The decision to have such a test is a momentous one and should not be taken lightly. Most centers that do predictive testing, including ours, require a period of counseling before and after the test. Onset is usually in mid-life, but can occur any time from childhood to old age. The initial signs of this disorder may be subtle. Overview Huntington's disease is a rare, inherited disease that causes the progressive breakdown degeneration of nerve cells in the brain.

Request an Appointment at Mayo Clinic. Autosomal dominant inheritance pattern Open pop-up dialog box Close. Autosomal dominant inheritance pattern In an autosomal dominant disorder, the mutated gene is a dominant gene located on one of the nonsex chromosomes autosomes. In vitro fertilization Open pop-up dialog box Close. In vitro fertilization During in vitro fertilization, eggs are removed from mature follicles within an ovary A.

Share on: Facebook Twitter. Show references AskMayoExpert. Huntington Disease. Mayo Clinic; Huntington's disease: Hope through research. National Institute of Neurological Disorders and Stroke.

Accessed Feb. Ferri FF. Huntington disease. In: Ferri's Clinical Advisor Elsevier; A physician's guide to the management of Huntington's disease. Huntington's Disease Society of America. National Library of Medicine. Genetics Home Reference. Suchowersky O. Huntington disease: Management. Riggin EA. AllScripts EPSi. Mayo Clinic.