Mutations in the HTT gene.
Huntington disease-caused by mutations in the HTT gene. The inherited mutation that causes Huntington disease is known as a CAG trinucleotide repeat expansion. This mutation increases the size of the CAG segment in the HTT gene. People with Huntington disease have 36 to more than 120 CAG repeats. Huntington’s Disease After the Cheering. In 1983, optimism swept the world of brain science: a marker had been found for the gene for Huntington’s disease—an invariably fatal affliction that had dogged certain families in America for 12 generations. A long, difficult decade later, scientists made another thrilling announcement: The gene had been found.  Huntington's Disease (HD) is a progressive brain disorder caused by a defective gene. This disease causes changes in the central area of the brain, which affect movement, mood and thinking skills. About Huntington's Disease. George Huntington, M.D., who first described the disease that bears his name. Huntington's disease is a progressive brain disorder caused by a single defective gene on chromosome 4 — one of the 23 human chromosomes that carry a person’s entire genetic code. This defect is dominant, meaning that anyone who inherits it from a parent with Huntington's will eventually develop the disease Causes: Huntington’s Disease is caused by a single defect on a single chromosome. This gene is found in every human being and contains a triplet repeat sequence. In a case of Huntington’s Disease, the gene contains an abnormally large number of triplet repeats. The disease does not skip generations.  Humans have 46 chromosomes (23 pairs). The faulty gene that causes Huntington's disease is found on chromosome number four. The normal copy of the gene produces a protein called huntingtin, but the faulty gene contains an abnormal region of what are called CAG repeats. This area is larger than normal and produces a mutant form of huntingtin. A parent with the Huntington's disease gene has one good copy of the gene and one faulty copy. Their child will inherit one of these genes. Therefore, there's a 50:50 chance that the child will get the faulty gene and develop Huntington's disease. Such is the current state of Huntington's disease (HD), an adult-onset autosomal dominant disorder. Today, researchers can literally measure the HD-associated gene, called huntingtin (HTT), by determining the number of repeats of a set of three specific bases within this gene. HD is a rare, adult-onset, autosomal dominant, progressive neurodegenerative disease. George Huntington (Figure 1) was the first person to provide a comprehensive description of adult-onset HD in 1872; he was only 22 years old at the time. Huntington's disease (or Huntington's chorea) is a neurological disorder that is caused by a faulty gene on chromosome number 4. As such, it can not be caught, but can only be … passed from parents to children. A person who has a parent with HD has a 50%-50% chance of inheriting the gene.  Huntington disease is a progressive brain disorder that causes uncontrolled movements, emotional problems, and loss of thinking ability (cognition). Adult-onset Huntington disease, the most common form of this disorder, usually appears in a person's thirties or forties. The HTT gene provides instructions for making a protein called huntingtin. Although the function of this protein is unknown, it appears to play an important role in nerve cells (neurons) in the brain. The HTT mutation that causes Huntington disease involves a DNA segment known as a CAG trinucleotide repeat.
http://ghr.nlm.nih.gov/gene/HTT http://www.dana.org/Cerebrum/Default.aspx?id=39308 http://www.alz.org/dementia/huntingtons-disease-symptoms.asp http://www.alzfdn.org/RelatedIllnesses/huntingtondisease.html http://www.nhs.uk/Conditions/Huntingtons-disease/Pages/Causes.aspx http://www.nature.com/scitable/topicpage/Huntington-s-Disease-The-Discovery-of-the-851 http://www.answers.com/Q/What_allele_and_chromosome_is_huntington%27s_disease_found_on http://ghr.nlm.nih.gov/condition/huntington-disease
which chromosome is huntington's disease found on