Links for Keyword: Huntingtons
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Dara Mohammadi As the small motorboat chugs to a halt, three travellers, wind-beaten from the three-hour journey along the Atrato river, step on to the muddy banks of Bellavista, an otherwise inaccessible town in the heart of the heavily forested north-west of Colombia. They swing their hessian bags – stuffed with bedsheets, dried beans and cuddly toys – to their shoulders and clamber up a dusty path. Tucked inside the bag of one of the travellers, neuropsychologist Sonia Moreno, is the reason they are here: a wad of unfinished, hand-drawn charts of family trees. The people whose names are circled on the charts have Huntington’s disease, an incurable genetic brain disorder that usually starts between the ages of 35 and 45 years. It begins with personality changes that can make them aggressive, violent, uninhibited, anxious and depressed. The disease progresses slowly, robbing them first of the control of their body, which jerks and twists seemingly of its own will, and then their ability to walk, talk and think until, about 20 years after the symptoms first begin, they die. Their children, each of whom has a 50% chance of inheriting the disease, watch and wait to see if it will happen to them. It is in this way that the disease strangles families. With Moreno is Ignacio Muñoz-Sanjuan, vice president of translational biology at CHDI Foundation, a US nonprofit research organisation that aims to find ways to prevent or slow down the progression of the disease. The foundation spent $140m–$150m (£97m-£104m) on research last year, but Muñoz-Sanjuan is not here on official business. He’s here for Factor-H, an initiative he founded four years ago to help with the other end of the problem – poor families with Huntington’s struggling in Latin America. © 2016 Guardian News and Media Limited o
By Hanae Armitage CHICAGO, ILLINOIS—Huntingtons disease, a neurological condition caused by brain-destroying mutant proteins, starts with mood swings and twitching and ends in dementia and death. The condition, which afflicts about 30,000 Americans, has no cure. But now, a new gene-editing method that many believe will lead to a Nobel Prize has been shown to effectively halt production of the defective proteins in mice, leading to hope that a potent therapy for Huntingtons is on the distant horizon. That new method is CRISPR, which uses RNA-guided enzymes to snip out or add segments of DNA to a cell. In the first time it has been applied to Huntingtons disease, CRISPR’s results are “remarkably encouraging,” says neuroscientist Nicole Déglon of the University of Lausanne in Switzerland, who led the mouse study, results of which she and her co-researcher Nicolas Merienne shared yesterday at the Society for Neuroscience Conference in Chicago, Illinois. As neurological diseases go, Huntingtons is an ideal candidate for CRISPR therapy, because the disease is determined by a single gene, Déglon notes. A mutation in the gene, which codes for a normally helpful brain protein called huntingtin, consists of different numbers of “tandem repeats,” repeating segments of DNA that cause the protein to fold into a shape that is toxic to the brain. Déglon and her team wondered whether CRISPR could halt production of this dangerous molecule. Using a virus as a delivery vehicle, the researchers infected two separate groups of healthy adult mice with a mutant huntingtin gene, but only one group received the therapy: a CRISPR “cassette,” which includes DNA for the gene-editing enzyme Cas9 and the RNA to target the huntingtin gene. © 2015 American Association for the Advancement of Science
|By Tara Haelle The first step to treating or preventing a disease is often finding out what drives it. In the case of neurodegenerative disorders, the discovery two decades ago of what drives them changed the field: all of them—including Alzheimer's, Parkinson's, Huntington's and amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease)—involve the accumulation of misfolded proteins in brain cells. Typically when a protein misfolds, the cell destroys it, but as a person ages, this quality-control mechanism starts to fail and the rogue proteins build up. In Huntington's, for example, huntingtin protein—used for many cell functions—misfolds and accumulates. Symptoms such as muscular difficulties, irritability, declining memory, poor impulse control and cognitive deterioration accompany the buildup. Mounting evidence suggests that not only does the accumulation of misfolded proteins mark neurodegenerative disease but that the spread of the proteins from one cell to another causes the disease to progress. Researchers have seen misfolded proteins travel between cells in Alzheimer's and Parkinson's. A series of experiments reported in Nature Neuroscience in August suggests the same is true in Huntington's. In their tests, researchers in Switzerland showed that mutated huntingtin protein in diseased brain tissue could invade healthy brain tissue when the two were placed together. And when the team injected the mutated protein into a live mouse's brain, it spread through the neurons within a month—similar to the way prions spread, says Francesco Paolo Di Giorgio of the Novartis Institutes for BioMedical Research in Basel, who led the research. Prions are misfolded proteins that travel through the body and confer their disease-causing characteristics onto other proteins, as seen in mad cow disease. But it is not known if misfolded proteins involved in Huntington's convert other proteins as true prions do, according to Di Giorgio. © 2014 Scientific American
By David Brown, Charles Sabine, who spent more than two decades as a television reporter for NBC covering wars, revolutions and natural disasters, is familiar with something he calls “real fear.” He’s seen it in the eyes of people about to die or be killed. It chilled his blood when a Bosnian guerrilla held a gun to his chest as he stood near a bullet-pocked execution wall. He felt it when he walked point for his camera crew in Baghdad during Iraq’s sectarian war. But nothing terrified him like the news he got eight years ago after taking the gene test for Huntington’s disease, whose slow downward course toward death makes it one of mankind’s most dread afflictions. “I learned that the disease that took my father and is inflicting on my brother the same terrible decline in his prime will take me, too,” said Sabine, 53, an Englishman who worked for NBC for 26 years. And yet Sabine has turned that knowledge to a purpose that can only be called thrilling. He’s on a mission to make Huntington’s the model for a Hopeless Disease About Which There’s Hope. He wants to put it at the forefront of the “patient-centered care” movement, the effort to always ask patients what they consider success or hope to get out of treatment. He wants to make sure there are Huntington’s patients ready for clinical trials that are just around the corner. He wants to get everybody to think a little more sophisticatedly about genetic testing. Closer to home, he’s turning the knowledge of his biological fate into a tool to help him savor every day, be a good father and husband, make amends, not deceive. © 1996-2013 The Washington Post
Recycling is not only good for the environment, it’s good for the brain. A study using rat cells indicates that quickly clearing out defective proteins in the brain may prevent loss of brain cells. Results of a study in Nature Chemical Biology suggest that the speed at which damaged proteins are cleared from neurons may affect cell survival and may explain why some cells are targeted for death in neurodegenerative disorders. The research was supported by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. One of the mysteries surrounding neurodegenerative diseases is why some nerve cells are marked for destruction whereas their neighbors are spared. It is especially puzzling because the protein thought to be responsible for cell death is found throughout the brain in many of these diseases, yet only certain brain areas or cell types are affected. In Huntington’s disease and many other neurodegenerative disorders, proteins that are misfolded (have abnormal shapes), accumulate inside and around neurons and are thought to damage and kill nearby brain cells. Normally, cells sense the presence of malformed proteins and clear them away before they do any damage. This is regulated by a process called proteostasis, which the cell uses to control protein levels and quality. In the study, Andrey S. Tsvetkov and his colleagues showed that differences in the rate of proteostasis may be the clue to understanding why certain nerve cells die in Huntington’s, a genetic brain disorder that leads to uncontrolled movements and death.
By John McCarthy Maybe this discovery is interesting because it sheds therapeutic light on the dreaded neurodegenerative diseases that killed Woody Guthrie and Lou Gehrig. Or maybe it’s fascination with healthy cells, and yet another unsuspected complexity in how they work. What’s discovered: a previously unknown energy source in nerve cells. It propels the molecular “motors” that drag neurotransmitters from the nucleus where they’re made. The “motors” are assemblies of molecules. They walk like clumsy robots, with a staggering gait, dragging a capsule of neurotransmitter “bullets” along microtubule “highways” between nucleus and synapses. They move by flinging their boot-like feet (lavender blobs, in the image) forward, a billionth of a meter at each step. (A superb animation of “motors” in action is XVIVO’s “Life of a Cell” (at ~1:15 of playing time)). When the cargo finally arrives at the synapses, neurotransmitters are loaded into compartments at the synapse’s interior face, like bullets into a magazine. They are ready to be “fired” across a synapse to signal an adjoining neuron. It’s this transport of neurotransmitter “bullets” that failed in Guthrie’s and Gehrig’s nerve cells. Their synapses had nothing to fire. What powers the flinging that moves those boots? Previously, the answer has been specialized molecules (acronym: ATP) spewed into the cell’s fluid interior by mitochondria. The boots, it was thought, powered each step by grabbing a floating ATP and blowing it up like a firecracker. © 2013 Scientific American
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 17978 - Posted: 04.02.2013
By Gary Stix 14 inSharHuntington’ disease, which killed folk singer Woody Guthrie, seems to put into overdrive the main chemical that turns on brain cells, ultimately leading to their death. The normal function of the neurotransmitter glutamate, the chemical overproduced in Huntington’s, is also intimately involved with learning. Researchers from Ruhr University and the University of Dortmund in Germany have been intrigued by the question of whether the neurodegeneration initiated by glutamate in this genetic disorder is all bad. Is it simply burning out brain circuits? Or might an excess of the chemical also help presymptomatic carriers of the Huntington’s gene or even patients with the disease itself, learn some things faster or better? “Neurotransmission causes cell death but we know from the vast amount of literature that learning processes very much depend on glutamate neurotransmission; so there may be two effects of one and the same process,” says Christian Beste of Ruhr University. “On the one hand this process may lead to neurodegeneration. But on the other hand, it may augment a cognitive process that depends on glutamate transmission.” Beste is the lead author on a paper published this month in Current Biology that found that those who have the genetic mutation for Huntington’s but who have yet to develop inevitable symptoms of the disease perform better on a learning task than a control group that lacks the mutation. The 29 Huntington’s gene carriers learned to detect twice as fast as the 45 controls a change in brightness of a small bar as its orientation on a computer screen altered. In fact, the Huntington’s carriers with the most pronounced mutations—the number of repetitions of a short DNA segment determines how early disease onset occurs—logged the best performance. © 2012 Scientific American,
By Kathleen Raven A compound already sitting on the shelves of biomedical laboratories and emergency room supply closets seems to interrupt the formation of neurodegenerative protein clumps found in Huntington’s disease, according to a preliminary animal study published August 7 in the Journal of Neuroscience. This versatile agent, called methylene blue, gets a mention in medical literature as early as 1897 and was used to treat, at one time or another, ailments ranging from malaria to cyanide poisoning. The U.S. Food and Drug Administration has never formally approved it as a therapy for any illnesses. But that fact hasn’t stopped biomedical researchers from tinkering with the agent’s apparent ability to improve cognitive function. And although the new paper out today relies on a Huntington’s disease model in flies and mice, scientists are hopeful. "Because of existing knowledge of methylene blue and the fact that it’s not harmful to humans, I would hope that progress toward clinical trials could go relatively quickly," says Leslie Thompson, a neurobiologist at University of California–Irvine and lead author on the new study. Huntington’s disease occurs when the C-A-G sequence of DNA base pairs repeat too often on the HTT gene, resulting in an abnormally long version of the huntingtin protein, that therefore folds incorrectly and forms clumps in the brain. The illness usually begins to affect people in their 30s and 40s, causing movement problems and early death. No drug is currently available to stop the disease from progressing. © 2012 Scientific American
By James Gallagher Health and science reporter, BBC News People with Huntington's disease, a debilitating brain condition, appear have a "protection" from cancer, according to a study in Sweden. Nearly 40 years of medical records showed patients with Huntington's had half the normal expected risk of developing tumours. Researchers, writing in The Lancet Oncology, said the reason was unclear. Cancer Research UK said the findings presented another avenue to explore in tackling cancer. Academics at Lund University analysed Swedish hospital data from 1969 to 2008. They found 1,510 patients with Huntington's disease. During the study period, 91 of those patients subsequently developed cancer. The authors said that was 53% lower than the levels expected for the general population. Huntington's is one of a group of illnesses called "polyglutamine diseases". Data from other polyglutamine diseases also showed lower levels of cancer. The authors said: "We found that the incidence of cancer was significantly lower among patients with polyglutamine diseases than in the general population. "The mechanisms behind the protective effects against cancer are unclear and further research is warranted." BBC © 2012
By msnbc.com staff and news services A 9-year-old Detroit-area girl whose battle with Huntington's disease drew attention after she was taunted online in 2010 by her grandmother's former neighbor has died. Michigan Memorial Funeral Home in Flat Rock, which is handling arrangements, says Kathleen Edward died Wednesday. One Facebook posting was of her doctored photo placed above a set of crossbones and another included a photo of her mother in the arms of the grim reaper. The conflict with the neighbor reportedly stemmed from a misunderstanding with the girl's family. After the Facebook taunts appeared, people worldwide voiced their support of the young girl on Facebook and raised money to send her on a shopping spree in 2010, according to the Detroit Free Press. Huntington's disease is a genetic, incurable brain disorder which, in children, can cause tremors, slow, rigid movements and seizures. Kathleen's mother also died from the degenerative disease in 2009, the newspaper reported. If one parent has Huntington's disease, a child has a 50 percent chance of getting it. Most people with Huntington's disease develop symptoms in their 40s or later, but when younger people get it, the disease tends to progress more quickly, according to the Mayo Clinic. "She suffered with this disease for a while, and she never complained," her grandmother, Rebecca Rose, told the Detroit Free Press. "She was always happy, always smiling." © 2012 msnbc.com
By Nick Bascom Scientists on the trail of treatments for Huntington’s disease may have found a way to track their success. A new study reports that patients with Huntington’s disease have higher levels of expression of a gene called H2AFY in their blood compared with healthy people. What’s more, patients treated with a drug that slows the effects of the disease had reduced levels of H2AFY activity compared with people given a placebo. The results suggest that H2AFY could serve as a tool for monitoring the progression of the disease and an indicator of whether prospective treatments are working, researchers report online October 3 in the Proceedings of the National Academy of Sciences. “Biomarker identification for Huntington’s disease is critically important for clinical trials,” says Leslie Thompson, director of the Interdepartmental Neuroscience Program at the University of California, Irvine, who was not involved in the study. Huntington’s disease is a hereditary movement disorder marked by involuntary bodily twitches and jerks. The damage the disorder does to nerve cells also causes severe depression and impairs a patient’s ability to reason clearly. “It’s a devastating disease,” and one for which there is no cure, says neurologist Clemens Scherzer of Brigham and Women’s Hospital in Boston, who led the new study. © Society for Science & the Public 2000 - 2011
By Tina Hesman Saey There’s a little Hannibal Lecter in all of us. But while the famous cannibal dined on chunks of his enemies and friends, most people stick to gnawing on themselves at a microscopic level. In fact, the cells of organisms from yeast to humans regularly engage in self-cannibalism. Cells chew on bits of their cytoplasm — the jellylike substance that fills their bellies — and dine on their own internal organs, although usually without the fava beans and Chianti. It may sound macabre, but gorging on one’s own innards, a process called autophagy, is a means of self-preservation, cleansing and stress management. “It has become evident that it is really an essential or vital function,” says Fulvio Reggiori, a cell biologist at the University Medical Center Utrecht in the Netherlands. A munch here gets rid of garbage that might otherwise clog the system. A nibble there rids cells of malfunctioning parts. One chomp disposes of invading microbes. In lean times, all that stands between a cell and starvation may be the ability to bite off and recycle bits of itself. And in the last decade or so it has become clear that self-eating can also make the difference between health and disease. “Too much or too little autophagy is a problem,” says Daniel Klionsky, a cell biologist at the University of Michigan in Ann Arbor. A cell that bites off more than it can chew can kill itself, Klionsky says. A few rare genetic diseases are linked to an excess of unsuccessful autophagy: The muscles of people with Danon disease, Pompe disease and X-linked myopathy can become weak after filling up with Pac-Man–like structures that put the bite on the cell’s insides but can’t finish digesting. © Society for Science & the Public 2000 - 2011
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 15110 - Posted: 03.17.2011
by Wendy Zukerman People with Huntington's disease show symptoms more than a decade before they are likely to get a clinical diagnosis. These early effects of the disease don't affect day-to-day functioning, but they will help drug developers evaluate treatments that target the early stages of the disease. Huntington's is a fatal and incurable brain condition whereby a faulty gene makes brain cells commit suicide en masse. It causes problems in communication, mental processes and movement. Within the faulty gene, a specific sequence called CAG is repeated too many times. Although "environmental" factors such as exercise may slow Huntington's progression, the number of CAG repeats accurately predicts the age of illness onset. For example, someone with around 40 repetitions is likely to get their first symptoms in late middle age. Previous studies have found that several years before the disease manifests itself, the brains of people with the mutation undergo subtle changes, with a thinning of the regions involved in motor function. To find out whether how these changes affected people with the Huntington's gene before clinical symptoms begin, Julie Stout of Monash University in Melbourne, Australia, and colleagues selected 119 people who had the gene but no symptoms. The volunteers were predicted to get clinical symptoms around 10 years later, on average, based on their age and number of CAG repeats. © Copyright Reed Business Information Ltd.
Australian researchers studying Huntington's disease in human embryonic stem cells say that signs of the disease can be seen in cells just a few days old. The researchers, from Macquarie University's Australian Proteome Analysis Facility (APAF) and IVF Sydney, say they are the first in the world to study Huntington's disease in human embryonic stem cells. Dr. Leon McQuade, the senior scientific officer at APAF, presented the research Wednesday at the Human Proteomics Organization congress in Sydney. Huntington's disease is a fatal genetic brain disorder affecting about one in every 10,000 Canadians, according to the Huntington Society of Canada. Symptoms are usually first seen in middle age and become progressively worse. Until now, studies into how the disease develops could only be done in mouse models, which do not always accurately reflect the disease in humans, or in brain cells of patients after they have died. Recently, researchers have examined human embryonic stem cells taken from five- to seven-day-old embryos that were known to have Huntington's and had been donated by couples undergoing genetic testing before IVF. © CBC 2010
Steve Connor Huntington’s disease is a relatively rare genetic disorder that you wouldn’t wish upon your worst enemy. If you carry a single copy of the affected gene you are destined to die a horrible death involving uncontrollable movements, psychiatric disturbances and progressive dementia. The first symptoms typically occur around the age of 40, and it takes between 10 and 15 more years for the gradual neurodegeneration to end life. Ten years after the excitement of mapping the human genome, and the revolution in the understanding of genetic disorders that the achievement has brought, it is easy to forget that some of those directly affected by inherited diseases have seen little in terms of practical benefit. The gene involved in Huntington’s disease was mapped to chromosome 4 in 1983 by a team led by Jim Gusella at Harvard Medical School in Boston, but it took another 10 years of intensive effort to isolate and clone the gene itself. This allowed scientists to find the type of changes, or mutations, that cause the disorder – the mutated gene has about two or three times the normal number of ‘GAG repeats. I remember on both occasions – in 1983 and 1993 – there were optimistic predictions that the discoveries would soon lead to a test for the carriers of the Huntington’s mutation and effective treatments – even possibly a cure – for the disease. The sad fact is that although a relatively cheap and accurate diagnostic test for the Huntington’s mutation has existed for some years, this medical advance has for the affected families arguably produced more misery than it has eradicated. For a start, there has been no accompanying revolution in treatment, largely because there are so few affected people (estimated to be about 12,000 in Britain) to make it worth the expense and effort of the drug companies to develop new therapies. ©independent.co.uk
By NICHOLAS BAKALAR George Huntington first described the devastating neurological illness that bears his name in 1872, but The New York Times did not mention it until 1913 — when “Huntington’s chorea” was listed as an item on the agenda of a medical convention in Washington. The name came up again in 1929, but again only in a list of subjects to be discussed at a doctors’ meeting. In 1936, Huntington’s chorea appeared twice, once in each of two 1,000-word letters to the editor whose central subject was eugenics, improving the species by regulating human reproduction. Huntington’s chorea was listed as one of five diseases whose sufferers might be considered candidates for voluntary sterilization. (The others were feeblemindedness of the familial type, schizophrenia, manic-depressive psychosis and epilepsy.) No details about Huntington’s were offered in either letter, and in one of them, written by a doctor in Montclair, N.J., the subheads “Many Defectives” and “Stemming Racial Decay” reveal a sensibility quite different from today’s. Sterilization, the doctor concluded, was “an indispensable part of any farsighted and humanitarian program for dealing with society’s great burden of mental disease, deficiency and dependency.” The first description of the illness appeared on Aug. 9, 1959, in an unsigned article headlined “Report on a Hereditary Illness.” The article described a study of Huntington’s chorea that had been published that month in Psychiatric Bulletin, a British medical journal. Copyright 2009 The New York Times Company
By Tina Hesman Saey Researchers may have discovered how a neuron-killing protein selects its victims — it has an accomplice. Scientists identified a mutant form of the protein huntingtin as the culprit in Huntington’s disease in 1993. The protein is found in every cell in the body, but it only turns deadly in brain cells — particularly cells in the striatum, a part of the brain that helps control movement. Why mutant huntingtin preferentially kills those cells has been a mystery. Now, researchers at Johns Hopkins University in Baltimore report in the June 5 Science that a protein called Rhes may goad huntingtin into killing brain cells in the striatum, leading to Huntington’s disease. If confirmed, the finding could provide new avenues for developing therapies to treat the fatal neurodegenerative disease, says Nancy Wexler, president of the Hereditary Disease Foundation and a Huntington’s disease researcher at Columbia University. “This study really gave me a peek into what the future of the field might look like,” says William Seeley, a neurologist at the University of California, San Francisco’s Memory and Aging Center. Many researchers study the role of individual proteins in causing or preventing disease, but few studies before this one go beyond the molecular level and explain why neurodegenerative diseases attack only certain parts of the brain. “What makes it so special for me is that it builds a bridge back to the anatomy of the disease,” Seeley says. © Society for Science & the Public 2000 - 2009
WASHINGTON - Federal regulators on Friday cleared the first treatment approved in the United States for Huntington’s, a rare inherited disease that causes uncontrolled movements, deterioration of mental abilities and, ultimately, death. The medication, called Xenazine, will not cure the condition—and it has some potentially serious side effects, such as raising the risk of suicidal behavior. However, it does provide relief for a major disabling symptom of Huntington’s: the jerky, involuntary movements known by the medical term chorea and force many patients to live as shut-ins. “A lot of patients won’t go out because they are embarrassed by those movements,” said Dr. Frederick J. Marshall, a University of Rochester Medical Center neurologist who led the clinical study that provided evidence of the drug’s effectiveness. “Suppressing those movements means a lot to people with Huntington’s disease.” The disease affects only about 30,000 patients in the United States. Developing and testing medications for such a small population is a difficult process, with uncertain financial rewards. So the Food and Drug Administration granted Xenazine a special “orphan drug” designation that provides additional years of patent protection and allows the manufacturer, Prestwick Pharmaceuticals, to write off some development costs. The medication had already been approved in Canada, Europe and Australia. © 2008 The Associated Press.
Researchers at Rush University Medical Center, Chicago, and Ceregene Inc., San Diego, have successfully used gene therapy to preserve motor function and stop the anatomic, cellular changes that occur in the brains of mice with Huntington’s disease (HD). This is the first study to demonstrate that, using this delivery method, symptom onset might be prevented in HD mice with this treatment. Results of the study were published in the Proceedings of the National Academy of Sciencesof the United States, June 13, 2006. “This could be an important step toward a disease modifying therapy,” says co-author Jeffrey H. Kordower, Ph.D., director of the Research Center for Brain Repair at Rush. “We could potentially be stopping the disease process in its tracks, delaying symptoms from ever showing up.” Huntington's disease is an inherited degenerative disease that progressively robs patients of the ability to think, judge appropriately, control their emotions and perform coordinated tasks. HD typically begins in mid-life, between the ages of 40 and 50. There is no effective treatment or cure for this fatal illness that affects 30,000 Americans and places another 75,000 at risk. Kordower says this research, if eventually applied to humans, could help those who have HD or, due to the presence of a genetic test, are known to be destined to get HD. © Rush University Medical Center,
Peter Aldhous Huntington’s disease may be about to meet its match with the development of a therapy designed to knock out production of the defective protein that causes the condition. Huntington’s is an untreatable inherited disease in which repetitive sequences of DNA lead to the production of a faulty version of a protein called huntingtin, giving it multiple copies of the amino acid glutamine. As adults, its victims lose their cognitive abilities, suffer involuntary movements and, after a decade or more, die. This week at the American Society of Gene Therapy meeting in Baltimore, Maryland, researchers led by Beverly Davidson of the University of Iowa described their progress treating the disease with a technique called RNA interference, or RNAi. RNAi uses short sequences of RNA just over 20 bases long to trigger a natural “gene-silencing” mechanism, shutting down the production of specific proteins by targeting the RNA that carries the instructions for making them. Last year, Davidson raised the hopes of people carrying the Huntington’s gene when she used engineered viruses to treat mice with the mutated gene. The viruses produce “small interfering” RNA sequences designed to block the RNA carrying the message to make huntingtin. © Copyright Reed Business Information Ltd.