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For other articles and previous issues click here. September 6, 2004 Frontotemporal
Dementia Misdiagnosed and misunderstood, frontotemporal dementia (FTD) can masquerade as many different disorders: psychiatric conditions, stroke, and, most commonly, Alzheimer’s disease. But make no mistake: FTD is a devastating neurodegenerative condition all its own, primarily striking people in their 40s and 50s. According to University of Pennsylvania neurologist Murray Grossman, MD, EdD, FTD is more common than once thought. “It seems to be as frequent as Alzheimer’s disease in the group of folks younger than 65,” he says. “It’s only recently that we’ve recognized how frequent and important a disorder this is—it’s only been treated over the course of the past 10 years or so.” But despite the increasing occurrences, “one of the biggest problems we have is simply getting physicians to consider FTD as a diagnosis,” says Helen-Ann Comstock, founder and chair of the Association for Frontotemporal Dementias (AFTD). “There’s been virtually no funding or research, and there’s little information available. There aren’t any hard numbers of how many people are actually afflicted with FTD. It’s where Alzheimer’s was 20 years ago in terms of the lack of recognition, information, knowledge. Many physicians might not even know about it.” What Is FTD? “Anyone can get FTD, but we don’t know for sure yet what causes one person to get it and not another,” says Grossman, chair of the AFTD’s medical advisory council. “In a small number of people—approximately 6% to 7%—it’s caused by a disorder of a protein in the brain called tau, which can be inherited. Tau acts like the blood vessels and skeleton of brain cells, so when there’s a disorder with tau, brain cells shrink, atrophy, and die. “This ‘tauopathy’ is a common theme of FTD, and that’s a good thing because we know a lot about tau,” he continues. “We know that it’s coded in human chromosome No. 17, and we know that a small percentage of FTD patients have a disorder of tau due to a mutation of this chromosome. But as we learn more about it, we make rapid progress toward being able to halt and even cure this condition by stabilizing tau in the brain.” Grossman adds that tau is one of the features that contribute to Alzheimer’s disease as well. “One of the things that goes wrong in the brain that leads to Alzheimer’s is the abnormal accumulation of the tau protein. So whatever we learn about tau can be used to help treat both FTD and Alzheimer’s patients.” (See sidebar for more information on tau.) Signs and Symptoms Age isn’t the only indicator, says Grossman. “FTD presents in two ways,” he explains. “One is a disorder of social compartment and personality. People can become quite inappropriate, uninhibited, and quite unlike themselves. They might walk up to complete strangers on the street and make inappropriate statements or grab food off plates in restaurants if they’re hungry.” In other instances, the behavior changes might not be as drastic, says Comstock. “One of the strange things my husband did was actually not that strange, but definitely strange for him,” she says. “We were involved in a community fund-raising project, and he suggested we collect aluminum cans for recycling as a fund-raiser. He became chair of the project, and he really threw himself into it. At first, it wasn’t too noticeable… He had janitors and cooks at the school collecting cans, and one time I picked him up at the airport and he had organized the flight attendants to save the cans. “Soon, though, it became too much,” she continues. “If we went to a friend’s house, he would immediately go to the kitchen to make sure they hadn’t thrown any cans away. Then I’d start to hear from friends that they’d seen him on the side of the road picking up cans or climbing into a dumpster. The last straw was when I went to his office and it was literally bulging with sacks of these cans. It was completely out of hand, and yet he was raising money for a good cause, so it was hard to be opposed to it. But that’s the sort of thing it can appear as—he was doing something that was to a point acceptable, but then it just went beyond.” Grossman says the other main symptom of FTD is the loss of the power to use or comprehend both written and spoken words. “It’s called progressive aphasia, a disorder of language that gets worse as time goes on,” he explains. “Most times it’s associated with stroke. Patients have difficulty understanding meanings of words, retrieving the words they want to use when speaking, and taking words and forming them into sentences.” “It’s a very difficult thing to deal with, especially when it strikes so young,” says Comstock. “Over time, my husband said less and less and eventually said nothing at all.” Implications of FTD “There’s a tremendous amount of stress in the beginning when you don’t know what’s going on with the abnormal behavior,” says Comstock. “It creates problems within the family and workplace because people aren’t aware that this behavior is caused by an illness. In some cases, families have been instituting divorce proceedings because it’s become such a difficult situation and they haven’t gotten to a neurologist to figure out what’s going on. “When you finally find out what it is,” she continues, “you certainly aren’t happy about the cause, but it’s a relief to know that there’s a reason for the behavior.” But with that relief also comes a sense of despair. “When we first took my husband to the neurologist,” says Comstock, “he immediately said that it could be a brain tumor, which is actually what we hoped it was—as strange as that sounds—because at least a brain tumor would have been treatable. FTD is not.” Grossman says the fact that FTD most often strikes in the preretirement years can have a different set of consequences for patients and their families. “We’re talking about people who are younger, often still working, and who have young families,” he says. “Most of the time, these families haven’t had the chance to put together any resources to support this long, progressive disorder.” Since so little research has been done, government aid is often not available for FTD. “Many people have difficulty getting a Medicare disability decision about FTD,” says Comstock. “Physicians need to know proper coding and verbiage to get it accepted.” “Another important issue,” Grossman adds, “is that many of these patients can be the primary decision makers in terms of planning and organizing for their family. This can mean significant implications for a family’s economy.” The Road to Progress “Our No. 1 desire is to have NIH [the National Institutes of Health] fund a prevalence study so that we can officially say, ‘This is how many people are suffering from FTD,’” says Comstock. “We can probably never get any kind of pharmaceutical company interested in developing a medication for treatment until we can give more information about the number of people who have it, but we can’t get those numbers without the NIH’s help.” Despite that, Comstock remains optimistic. “I feel that we’re moving forward, but there’s still a lot to do,” she says. “But we do have the most wonderful medical people involved with the association and a lot of terrific caregiver families. By working together, we’re really going to make a difference here.” — Kara McDonald is an editorial assistant at For the Record. Tauopathies: New Discoveries,
New Knowledge Within the last few years, more attention has been focused on the other hallmark feature of AD—the “tangles” of abnormal tau protein. More is being learned about tau and what happens to change it in the AD process. Scientists are discovering that these tau tangles, along with extensive neuron loss and gliosis (a kind of tissue scarring in the brain), are the major feature of a number of neurodegenerative diseases. A consensus is emerging that these diseases should be called “tauopathies.” Tauopathies include frontotemporal dementia (FTD), Pick’s disease, corticobasal degeneration, familial FTDP-17, progressive supranuclear palsy, amyotrophic lateral sclerosis/parkinsonism-dementia complex of Guam, and motor neuron disease. Tau is a protein commonly found throughout the central nervous system. Six forms of tau are found in the adult human brain and each is maintained in a constant proportion. Tau binds and helps stabilize microtubules, a component of the nerve cell’s internal support structure or skeleton. In the healthy cell, microtubules form structures like train tracks, which guide nutrients and other molecules from the cell body down through the axon. Tau, therefore, plays a vital role in ensuring a nerve cell’s survival by supporting its structure and facilitating transport. What Goes Wrong? Starting in 1998, scientists took a major step forward when they found that mutations in the gene that directs the production of tau cause one particular tauopathy—frontotemporal dementia with parkinsonism linked to chromosome 17, or FTDP-17. These mutations appear to lead to problems in two ways: by forming mutant tau proteins in cells or changing the proportion of the forms of tau normally expressed in the brain. These changes promote tau aggregation into filaments and harm the ability of tau to bind to microtubules. Scientists have a growing body of clues, evidence, and facts about tau tangles and what goes wrong. The puzzle is that this pathologic process gives rise to such a wide range of disorders and diseases. These diseases share a number of characteristics, but they also each have distinct features that set them apart from each other, and from AD. This suggests to scientists that environmental and other genetic factors also must play a role in the cause and development of tauopathic conditions. Questions Persist • What roles do environmental and other genetic factors play in the development of tauopathies, and how do they contribute to the clinical characteristics of these diseases? • In what different ways does the abnormal tau expressed in AD and FTD contribute to the development of these diseases? • Which feature of AD is responsible for the dysfunction and death of neurons—beta-amyloid plaques or tau-containing tangles? If they both play a role, what are those roles and how might they interact? How is the process of plaque formation related to tangle formation? Progress is being made, however, giving rise to hopes that someday we will have effective treatments and perhaps even preventive measures for these devastating diseases. — Source: Alzheimer’s Disease Education & Referral Center Learn More About Frontotemporal
Dementia You can also write to the association for brochures, newsletters, and caregiver surveys at: The Association of Frontotemporal Dementias |
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