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By Brady Dennis In recent months, Pasadena-based Genervon has galvanized many patients with ALS by repeatedly touting the results of 12-week, 12-person trial involving the company's drug, GM604. The company asserted its early results were “statistically significant,” “very robust” and “dramatic.” It also has said it "submitted an accelerated approval application" to the FDA which, if approved, "would allow immediate access" to patients with ALS, also known as Lou Gehrig's disease. But the Wall Street Journal reported Monday that Genervon said in an email that it is “at the point of communicating with FDA about whether [the agency] would accept our formal application” for accelerated approval. In other words, the company has not yet submitted a New Drug Application, a step needed to officially set the FDA approval process in motion. The company's acknowledgement that it has not filed an NDA appears to contradict earlier press releases and statements made by the firm's owners, Winston and Dorothy Ko -- or at least to have sown confusion about the actual status of GM604. In one February press release, for example, the company said that in a meeting with the FDA, "three times during the one-hour meeting we requested that the FDA grant GM604 accelerated approval." Asking, however, is not the same as filing the necessary paperwork and the accompanying data required for the FDA to accept it as sufficient. The difference might seem to be a matter of semantics. But the real-world consequence is that, if Genervon has no application pending at the FDA, there is no imminent decision for the FDA to make about approving GM604.
By Amy Ellis Nutt and Brady Dennis For people with amyotrophic lateral sclerosis, which attacks the body’s motor neurons and renders a person unable to move, swallow or breathe, the search for an effective treatment has been a crushing disappointment. The only drug available for the disease, approved two decades ago, typically extends life just a few months. Then in the fall, a small California biotech company named Genervon began extolling the benefits of GM604, its new ALS drug. In an early-stage trial with 12 patients, the results were “statistically significant,” “very robust” and “dramatic,” the company said in news releases. Such enthusiastic pronouncements are unusual for such a small trial. In February, Genervon took an even bolder step: It applied to the Food and Drug Administration for “accelerated approval,” which allows promising treatments for serious or life-threatening diseases to bypass costly, large-scale efficacy trials and go directly to market. ALS patients responded by pleading with the FDA, in emotional videos and e-mails, to grant broad access to the experimental drug. Online forums lit up, and a Change.org petition calling for rapid approval attracted more than a half-million signatures. “Why would anyone oppose it?” asked ALS patient David Huntley in a letter read aloud in the past week at a rally on Capitol Hill. Huntley, a former triathlete, can no longer speak or travel, so his wife, Linda Clark, flew from San Diego to speak for him.
By Kate Baggaley Mutations on a gene necessary for keeping cells clean can cause Lou Gehrig’s disease, scientists report online March 24 in Nature Neuroscience. The gene is one of many that have been connected to the condition. In amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease, nerve cells that control voluntary movement die, leading to paralysis. Scientists have previously identified mutations in 29 genes that are linked with ALS, but these genes account for less than one-third of all cases. To track down more genes, a team of European researchers looked at the protein-coding DNA of 252 ALS patients with a family history of the disease, as well as of 827 healthy people. The team discovered eight mutations on a gene called TBK1 that were associated with ALS. TBK1 normally codes for a protein that controls inflammation and cleans out damaged proteins from cells. “We do not know which of these two principle functions of TBK1 is the more relevant one” to ALS, says coauthor Jochen Weishaupt, a neurologist at Ulm University in Germany. In cells with one of the eight TBK1 mutations, the protein either is missing or lacks components that it needs to interact with other proteins, the researchers found. TBK1 mutations may explain 2 percent of ALS cases that run in families, which make up about 10 percent of all incidences of the disease, Weishaupt says. © Society for Science & the Public 2000 - 2015
By Gary Stix Everyone knows that ALS is a very bad disease, an awareness underscored by the recent Ice Bucket Challenge. The death of neurons that results in paralysis can be caused by specific genetic mutations. But in most cases, single genes are not the culprit. So researchers have looked for other risk factors that might play a role. Studies have tagged cigarette smoking as a definite danger. Alcohol, another plausible suspect, has yielded equivocal results in previous investigations. To get a better read on ethanol (some earlier studies were small), researchers from Sweden’s Lund University looked at giant medical registries from that country, compiled at various times between 1973 and 2010. They found that individuals who were classified as problem drinkers were a little more than half as likely to be diagnosed with ALS as those who didn’t have “alcohol use disorder.” More than 420,000 problem drinkers were registered during the period surveyed—and there were 7965 patients who received an ALS diagnosis. The study, just reported in The European Journal of Neurology, controlled for gender, education and place of birth, among other factors. But it was unable to tell why drinking might help. It did lead, though, to a number of intriguing speculations. The researchers cited studies in rats, done by other groups, that indicated that ingestion of alcohol decreased the number of brain cells called astrocytes that bore high levels of a certain protein linked to the pathology of ALS. © 2015 Scientific American
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: 20562 - Posted: 02.07.2015
By Angelina Fanous After the height of the Ice Bucket Challenge last fall, I found myself at a dinner party where the conversation turned to A.L.S. — amyotrophic lateral sclerosis — the disease for which millions were dousing themselves to raise awareness and money. “Would you rather have A.L.S., Alzheimer’s, or Parkinson’s?” someone asked. All those diseases are devastating, but A.L.S. is unique in that it usually kills within two to three years of diagnosis. It was just a game to my friends, all of whom are in their 20s. Everyone chose A.L.S., agreeing that it would be the fastest and therefore easiest death. But I stayed silent. I hadn’t yet told my friends that I had been diagnosed with A.L.S. in July — two months after my 29th birthday. Had I been healthy, I might have answered A.L.S., too. But since my diagnosis, all I have wanted is more time. When I first noticed I couldn’t type with my left hand, the doctors narrowed down it down to two options: a treatable autoimmune disease or A.L.S. They initially began treating me for the autoimmune disease. About once a month, we shut down my immune system so it would stop attacking my central nervous system. But with no immune system I made regular visits to the E.R. “At least it’s not A.L.S.,” I consoled myself. When the treatment didn’t work and the weakness spread to my left leg and right hand, A.L.S. was the only remaining possibility. Still, I did that socially acceptable but also borderline insane thing where I sought second, third and fourth opinions. I voluntarily subjected myself to excruciating medical tests. I got shocked with electricity, had my spinal fluid drained, and underwent a surgery to remove a piece of my muscles and nerves, all in the hopes of finding a different diagnosis. All of the tests confirmed the diagnosis of A.L.S. © 2015 The New York Times Company
|William Mullen, Tribune reporter Researchers at Northwestern University say they have discovered a common cause behind the mysterious and deadly affliction of amyotrophic lateral sclerosis, or Lou Gehrig's disease, that could open the door to an effective treatment. Dr. Teepu Siddique, a neuroscientist with Northwestern's Feinberg School of Medicine whose pioneering work on ALS over more than a quarter-century fueled the research team's work, said the key to the breakthrough is the discovery of an underlying disease process for all types of ALS. The discovery provides an opening to finding treatments for ALS and could also pay dividends by showing the way to treatments for other, more common neurodegenerative diseases such as Alzheimer's, dementia and Parkinson's, Siddique said. The Northwestern team identified the breakdown of cellular recycling systems in the neurons of the spinal cord and brain of ALS patients that results in the nervous system slowly losing its ability to carry brain signals to the body's muscular system. Without those signals, patients gradually are deprived of the ability to move, talk, swallow and breathe. "This is the first time we could connect (ALS) to a clear-cut biomedical mechanism," Siddique said. "It has really made the direction we have to take very clear and sharp. We can now test for drugs that would regulate this protein pathway or optimize it, so it functions as it should in a normal state."
|By Lindsey Konkel For 28 years, Bill Gilmore lived in a New Hampshire beach town, where he surfed and kayaked. “I’ve been in water my whole life,” he said. “Before the ocean, it was lakes. I’ve been a water rat since I was four.” Now Gilmore can no longer swim, fish or surf, let alone button a shirt or lift a fork to his mouth. Earlier this year, he was diagnosed with amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease. In New England, medical researchers are now uncovering clues that appear to link some cases of the lethal neurological disease to people’s proximity to lakes and coastal waters. About five years ago, doctors at a New Hampshire hospital noticed a pattern in their ALS patients—many of them, like Gilmore, lived near water. Since then, researchers at Dartmouth-Hitchcock Medical Center have identified several ALS hot spots in lake and coastal communities in New England, and they suspect that toxic blooms of blue-green algae—which are becoming more common worldwide—may play a role. Now scientists are investigating whether breathing a neurotoxin produced by the algae may raise the risk of the disease. They have a long way to go, however: While the toxin does seem to kill nerve cells, no research, even in animals, has confirmed the link to ALS. As with all ALS patients, no one knows what caused Bill Gilmore’s disease. He was a big, strong guy—a carpenter by profession. One morning in 2011, his arms felt weak. “I couldn’t pick up my tools. I thought I had injured myself,” said Gilmore, 59, who lived half his life in Hampton and now lives in Rochester, N.H. © 2014 Scientific American
By Kelly Servick Using data from old clinical trials, two groups of researchers have found a better way to predict how amyotrophic lateral sclerosis (ALS) progresses in different patients. The winning algorithms—designed by non-ALS experts—outperformed the judgments of a group of ALS clinicians given the same data. The advances could make it easier to test whether new drugs can slow the fatal neurodegenerative disease. The new work was inspired by the so-called ALS Prediction Prize, a joint effort by the ALS-focused nonprofit Prize4Life and Dialogue for Reverse Engineering Assessments and Methods, a computational biology project whose sponsors include IBM, Columbia University, and the New York Academy of Sciences. Announced in 2012, the $50,000 award was designed to bring in experts from outside the ALS field to tackle the notoriously unpredictable illness. Liuxia Wang, a data analyst at the marketing company Sentrana in Washington, D.C., was used to helping companies make business decisions based on big data sets, such as information about consumer choices, but says she “didn’t know too much about this life science thing” until she got an unusual query from a client. One of the senior managers she worked with revealed that her son had just been diagnosed with ALS and wondered if Sentrana’s analytics could apply to patient data, too. When Wang set out to investigate, she found the ALS Prediction Prize. The next step, she said, was to learn something about ALS. The disease destroys the neurons that control muscle movement, causing gradual paralysis and eventually killing about half of patients within 3 years of diagnosis. But the speed of its progression varies widely. About 10% of patients live a decade or more after being diagnosed. That makes it hard for doctors to answer patients’ questions about the future, and it’s a big problem for testing new ALS treatments. © 2014 American Association for the Advancement of Science.
|By Amy Yee Pouring a bucket of ice water over one’s head may seem like a distant summer memory. But although the “ice bucket challenge” craze has died down, public awareness of amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s disease, has never been stronger. The viral video campaign raised $115 million from more than 3 million donors for the ALS Association. In one month, from July 29 to August 29, donors raised $100.9 million, compared with $2.8 million during the same period the previous year. In early October, the ALS Association began spending that money. It approved $21.7 million of funding for six programs and initiatives by groups that include the academic-industry partnership ALS Accelerated Therapeutics, the New York Genome Center, three California labs that form the Neuro Collaborative, and Project MinE, which will map the genomes of 15,000 people with ALS (about 10 percent of ALS patients have a family member with the disease). The grants focus on developing gene therapies for common ALS genes and exploring approaches to counter two major contributors to the disease, the inflammation of nervous tissue and misfolded proteins in brain cells that control movement. These efforts may not only someday lead to new treatments, but may also point to the cause of ALS. At the level of basic research, scientists do not have a dominant theory from which to work, notes Tom Jessell, a neuroscientist and co-director of Columbia University’s new Zuckerman Mind Brain Behavior Institute. Jessell is also the chair of the research advisory board of Project ALS, a nonprofit that identifies and funds ALS research. © 2014 Scientific American
By Roni Caryn Rabin When I was in college, my father David started walking with an odd, barely perceptible limp. He was in his mid-40s, a gregarious physician, teacher and researcher who was always upbeat. He told his four kids that he had a “back problem” — a deliberately vague cover story that I, for one, was willing to believe. I had never heard of the real culprit — amyotrophic lateral sclerosis, or A.L.S. In fact, no one had. A.L.S. was a disease in the shadows. During my father’s life, it didn’t even have its own advocacy organization. This was the early ’80s, long before support groups and the Internet and a colored ribbon for every cause. And it was way before ice bucket challenges. My parents continued to use their code — “back problem” — to talk about the disease. They used it to protect my younger sisters, who were about to start high school, but I think they were also protecting themselves. My mother was also a physician, and they both knew exactly what lay ahead. Saying “A.L.S.” out loud was too threatening. But soon there was no getting around it. My father’s legs were getting weaker, his muscles were wasting, and he started relying on a cane to get around. I was 19, and my mother and I were out running errands one afternoon when she pulled the car over to the curb and stopped. She told me the truth. This was no slipped disc. She laid it all out for me in black and white: A.L.S. is a progressive, degenerative neurological disease that causes paralysis in the entire body. It’s fatal. There is no cure. It sounded like something from a horror movie. Over the next five years, as my father’s health deteriorated, he remained remarkably determined. He ate a high-protein diet and swam laps every day in an attempt to maintain his muscle and fend off the atrophy caused by the disease. He kept on swimming laps in our next-door neighbor’s pool, even when he had to use a walker — and later a wheelchair — to get there. © 2014 The New York Times Company
By GRETCHEN REYNOLDS Amyotrophic lateral sclerosis has been all over the news lately because of the ubiquitous A.L.S. ice bucket challenge. That attention has also reinvigorated a long-simmering scientific debate about whether participating in contact sports or even vigorous exercise might somehow contribute to the development of the fatal neurodegenerative disease, an issue that two important new studies attempt to answer. Ever since the great Yankees first baseman Lou Gehrig died of A.L.S. in 1941 at age 37, many Americans have vaguely connected A.L.S. with athletes and sports. In Europe, the possible linkage has been more overtly discussed. In the past decade, several widely publicized studies indicated that professional Italian soccer players were disproportionately prone to A.L.S., with about a sixfold higher incidence than would have been expected numerically. Players were often diagnosed while in their 30s; the normal onset is after 60. These findings prompted some small, follow-up epidemiological studies of A.L.S. patients in Europe. To the surprise and likely consternation of the researchers, they found weak but measurable associations between playing contact sports and a heightened risk for A.L.S. The data even showed links between being physically active — meaning exercising regularly — and contracting the disease, raising concerns among scientists that exercise might somehow be inducing A.L.S. in susceptible people, perhaps by affecting brain neurons or increasing bodily stress. But these studies were extremely small and had methodological problems. So to better determine what role sports and exercise might play in the risk for A.L.S., researchers from across Europe recently combined their efforts into two major new studies. The results should reassure those of us who exercise. The numbers showed that physical activity — whether at work, in sports or during exercise — did not increase people’s risk of developing A.L.S. © 2014 The New York Times Company
By ZACH SCHONBRUN EAST RUTHERFORD, N.J. — Victor Cruz dumped a bucket of ice water on his head at home on Sunday and then stepped out on thin ice himself — challenging the Giants’ co-owners to do the same. Taking part in the Ice Bucket Challenge — a social media craze that raises awareness for Lou Gehrig’s disease (amyotrophic lateral sclerosis) — Cruz, a wide receiver, posted the video on his Twitter feed. “That water was cold, man,” Cruz said Monday. The Ice Bucket Challenge was started by friends and family members of Pete Frates, a 29-year-old from Beverly, Mass., who played baseball at Boston College and was found to have A.L.S., a neurodegenerative condition, in 2012. As a reward for withstanding the icy punishment, the participant gets to nominate another person, who has 24 hours to complete the task. Cruz aimed high, calling out the co-owners John Mara and Steve Tisch to step under the bucket themselves. Just before practice on Monday, the 59-year-old Mara, wearing a white Giants T-shirt and black shorts, allowed Cruz to dump a Gatorade tub filled with ice water over his head. Before doing so, Mara nominated the Jets’ owner, Woody Johnson; the Patriots’ owner, Robert K. Kraft; and Patriots Coach Bill Belichick to do the same. “Feels good,” a smiling Mara said in a video posted on the Giants’ team website. It is unclear if Tisch will follow suit. Those who fail to complete the task within 24 hours are asked to donate to A.L.S. research. © 2014 The New York Times Company
By Bill Briggs A Vietnam veteran swoops his hand through a row of baby vegetables, caressing the peppers on down to the kale. The plants are aligned in tidy, military order atop his backyard fence. He could spend hours describing his first garden. But he cannot utter a word. He can’t even eat his eventual harvest. So, Bob Hoaglan, 71, simply stands and grins at the spouts behind his Oxnard, Calif., home. Then, he grabs his primary communication tool, an LCD tablet, scribbling a stylus across the screen. He displays his words with a silent chuckle: “I don’t have a green thumb.” With a button click, he erases that sentence before composing another. His daily aim is to throw his body and brain into new pursuits. The crops — fresh life for a man facing mortality — help shove his disease to the back of his mind. He admits, though, he can’t keep it there: “I try,” he writes, “Sometimes it creeps up on me.” As he shows that message, the smile vanishes. Hoaglan was diagnosed with amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, nearly a year ago. Inside a malady that offers no cure or explanation, he embodies two intriguing clues that, a top researcher says, may whisper answers: Hoaglan served in the military, and he is a nice man. U.S. veterans carry a nearly 60 percent greater risk of contracting ALS than civilians, according to a white paper published in 2013 by the ALS Association, citing Harvard University research that tracked ex-service members back to 1910.
New findings reveal how a mutation, a change in the genetic code that causes neurodegeneration, alters the shape of DNA, making cells more vulnerable to stress and more likely to die. The particular mutation, in the C9orf72 gene, is the most common cause for amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease), and frontotemporal degeneration (FTD), the second most common type of dementia in people under 65. This research by Jiou Wang, Ph.D., and his colleagues at Johns Hopkins University (JHU) was published in Nature and was partially funded by the National Institutes of Health’s National Institute of Neurological Disorders and Stroke (NINDS). In ALS, the muscle-activating neurons in the spinal cord die, eventually causing paralysis. In FTD neurons in particular brain areas die leading to progressive loss of cognitive abilities. The mutation may also be associated with Alzheimer’s and Huntington’s diseases. DNA contains a person’s genetic code, which is made up of a unique string of bases, chemicals represented by letters. Portions of this code are divided into genes that provide instructions for making molecules (proteins) that control how cells function. The normal C9orf72 gene contains a section of repeating letters; in most people, this sequence is repeated two to 25 times. In contrast, the mutation associated with ALS and FTD can result in up to tens of thousands of repeats of this section.
Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 19328 - Posted: 03.06.2014
By LAUREN BRADY When I was 18 I watched my father perform what would be his final surgery. It was the summer of 2007 and I had just returned to Colorado after surviving my freshman year of film school at New York University. One day my dad invited me to observe a vitrectomy. And while I hadn’t a clue what this would entail I immediately accepted, honored by the invitation and determined not to faint. My father’s 21 years as an ophthalmologist produced over 15,000 operations, a private practice spanning three offices, and very little vacation time. While I sensed from an early age that the long hours were taxing on him I never felt an absence. In fact, my childhood was picturesque: two loving parents, a rowdy little brother whom I pushed around until he was big enough to push back, family trips in the Jeep to the Rocky Mountains. He was the dad with the Handycam at every soccer game and school play. He worked as a surgeon, but he lived for his children. The morning of the vitrectomy we left extra early because of a limp in my dad’s right leg that had appeared a few months earlier and had gradually worsened. He suspected it was a pinched nerve and had been meaning to get it checked out. In the interim, he had started using a chair during surgery. Walking toward the hospital entrance we encountered a fellow doctor who greeted me with the familiarity of someone who’d been exposed to years of my father’s wallet photos. He asked how I liked Greenwich Village, whether I had directed any films yet and if I had tried a bialy. We walked and talked until I noticed at one point that my dad was no longer part of the conversation. Turning around I realized he was a half block back pushing himself up from the ground. © 2014 The New York Times Company
By KATIE HAFNER While undressing for bed one night in 2009, Susan Spencer-Wendel noticed that the muscles in her left palm had disappeared, leaving a scrawny pile of tendons and bones. Her right hand was fine. She let out a yelp and showed the hand to her husband, who told her to go to the doctor. She was 42. Ms. Spencer-Wendel then entered a protracted period of denial. Adopted as an infant in Florida, she traveled from her home in West Palm Beach to find blood relatives living in Cyprus, who confirmed that there was no family history of her worst fear: amyotrophic lateral sclerosis, or A.L.S., the relentless disease that lays waste to muscles while leaving the mind intact. In June 2011, a doctor in Miami gave her a definitive diagnosis of A.L.S., smiling “like he was inviting me to a birthday party,” she writes in “Until I Say Goodbye: My Year of Living With Joy.” Patients with A.L.S., which is also known as Lou Gehrig’s disease, typically live no more than four years after the onset of symptoms. There is no cure. Ms. Spencer-Wendel thought she had prepared herself fully — that she would burst off the starting block like a sprinter to greet her fate. Instead, when she heard the news, “I dropped my head for the start ... and began to cry.” Her heart-ripping book chronicles what she did immediately after her diagnosis: she decided to embrace life while death chased her down. Instead of letting the world close in on her, she resolved to travel as far and as wide for as long as she could. She went to the Yukon with her best friend, Budapest with her husband, and the Bahamas with her sister. © 2013 The New York Times Company
by Emily Underwood Globs of protein clustered in the neurons that control muscles have long been the hallmark of amyotrophic lateral sclerosis (ALS), the fatal neurodegenerative disease also commonly known as Lou Gehrig's disease. Now, a study of the most commonly found mutant gene in people with ALS reveals an unexpected origin of some of those sticky masses, a finding that may offer drug developers a new target for treatments. Located on the ninth chromosome, which explains part of its unwieldy name, the C9orf72 gene has a bit of a stutter. A typical version in healthy people contains a stretch of DNA where a string of six genetic letters—GGGGCC—repeats up to 25 times. Scientists have recently found that in a sizable share of people with ALS and frontotemporal dementia (FTD), a less common neurological disease characterized by language, memory, and emotional problems, this repeat occurs many more times; some people have thousands of copies. Since these C9orf72 mutations were discovered in 2011, some researchers have speculated that the repeats interrupt production of the gene's normal protein, which serves some as-yet unknown, but vital function in motor neurons or other brain cells. Others have hypothesized that the mutation spawns a large, misshapen strand of RNA that grabs on to proteins such as TDP-43, which normally help process RNA, creating protein tangles that starve the cell of the machinery it needs to function. © 2010 American Association for the Advancement of Science
By KATIE HAFNER SEATTLE — Dr. Richard Wesley has amyotrophic lateral sclerosis, the incurable disease that lays waste to muscles while leaving the mind intact. He lives with the knowledge that an untimely death is chasing him down, but takes solace in knowing that he can decide exactly when, where and how he will die. Under Washington State’s Death With Dignity Act, his physician has given him a prescription for a lethal dose of barbiturates. He would prefer to die naturally, but if dying becomes protracted and difficult, he plans to take the drugs and die peacefully within minutes. “It’s like the definition of pornography,” Dr. Wesley, 67, said at his home here in Seattle, with Mount Rainier in the distance. “I’ll know it’s time to go when I see it.” Washington followed Oregon in allowing terminally ill patients to get a prescription for drugs that will hasten death. Critics of such laws feared that poor people would be pressured to kill themselves because they or their families could not afford end-of-life care. But the demographics of patients who have gotten the prescriptions are surprisingly different than expected, according to data collected by Oregon and Washington through 2011. Dr. Wesley is emblematic of those who have taken advantage of the law. They are overwhelmingly white, well educated and financially comfortable. And they are making the choice not because they are in pain but because they want to have the same control over their deaths that they have had over their lives. © 2012 The New York Times Company
Researchers have linked newly discovered gene mutations to some cases of the progressive fatal neurological disease amyotrophic lateral sclerosis — ALS, also known as Lou Gehrig’s disease. Shedding light on how ALS destroys the cells and leads to paralysis, the researchers found that mutations in this gene affect the structure and growth of nerve cells. ALS attacks motor neurons, the nerve cells responsible for controlling muscles. People with ALS experience such early symptoms as limb weakness or swallowing difficulties. In most people, the disease leads to death three to five years after symptoms develop, usually as a result of respiratory failure. Scientists at the University of Massachusetts Medical School, Worcester, collaborated with international ALS researchers to search for gene mutations in two large families with an inherited form of ALS. The researchers used a technique to decode only the protein-encoding portions of DNA, known as the exome, allowing an efficient yet thorough search of the DNA regions most likely to contain disease-causing mutations. This deep sequencing of the exome led to the identification of several different mutations in the gene for profilin (PFN1) which were present only in the family members that developed ALS. Further investigations of 272 other familial ALS cases across the world showed that profilin mutations were also found in a small subset (about 1 to 2 percent) of the familial ALS cases studied. The protein profilin is a key part of the creation and remodeling of a nerve cell's scaffolding or cytoskeleton. In fly models, disrupting profilin stunts the growth of axons — the long cell projections used to relay signals from one neuron to the next or from motor neurons to muscle cells. After identifying the PFN1 mutations in ALS patients, the researchers demonstrated that these mutations inhibited axon growth in laboratory-grown motor neurons as well. They also found that mutant profilin accumulated in clumps in neural cells, as has been seen for other abnormal proteins associated with ALS, Parkinson's and Alzheimer's.
By Erica Westly Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neuromuscular disease that affects about 130,000 people worldwide a year. The vast majority of patients are isolated cases with no known family history of the disease. They usually start developing symptoms of the loss of motor neurons in middle age and die within five years of diagnosis. Researchers know very little about what causes ALS. Now a recent study in Nature Biotechnology suggests that the neuron death associated with the disease may be caused by astrocytes, a type of brain cell that normally helps neurons. Previous research had suggested that astrocytes could become toxic in the rare form of ALS known to have genetic roots, and the study authors wanted to see if a similar phenomenon might happen in the more common isolated cases. The answer turned out to be yes: when they cultured astrocytes from those ALS patients, the healthy motor neurons in the culture began to die off after a few days. Other types of neurons were unaffected by the astrocytes, suggesting that they specifically harm the neurons involved in controlling the body’s movements. Lead author Brian Kaspar, a neuroscientist at Ohio State University, and his collaborators next will attempt to figure out what makes the astrocytes behave this way. If researchers can understand why motor neurons die in ALS, they may have a better chance of finding a cure. © 2012 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: 16298 - Posted: 01.26.2012