Chapter 7. Life-Span Development of the Brain and Behavior
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By Jessica Wright and SFARI.org It takes more mutations to trigger autism in women than in men, which may explain why men are four times more likely to have the disorder, according to a study published 26 February in the American Journal of Human Genetics. The study found that women with autism or developmental delay tend to have more large disruptions in their genomes than do men with the disorder. Inherited mutations are also more likely to be passed down from unaffected mothers than from fathers. Together, the results suggest that women are resistant to mutations that contribute to autism. “This strongly argues that females are protected from autism and developmental delay and require more mutational load, or more mutational hits that are severe, in order to push them over the threshold,” says lead researcher Evan Eichler, professor of genome sciences at the University of Washington in Seattle. “Males on the other hand are kind of the canary in the mineshaft, so to speak, and they are much less robust.” The findings bolster those from previous studies, but don't explain what confers protection against autism in women. The fact that autism is difficult to diagnose in girls may mean that studies enroll only those girls who are severely affected and who may therefore have the most mutations, researchers note. “The authors are geneticists, and the genetics is terrific,” says David Skuse, professor of behavioral and brain sciences at University College London, who was not involved in the study. “But the questions about ascertainment are not addressed adequately.” © 2014 Scientific American
By RON SUSKIND In our first year in Washington, our son disappeared. Just shy of his 3rd birthday, an engaged, chatty child, full of typical speech — “I love you,” “Where are my Ninja Turtles?” “Let’s get ice cream!” — fell silent. He cried, inconsolably. Didn’t sleep. Wouldn’t make eye contact. His only word was “juice.” I had just started a job as The Wall Street Journal’s national affairs reporter. My wife, Cornelia, a former journalist, was home with him — a new story every day, a new horror. He could barely use a sippy cup, though he’d long ago graduated to a big-boy cup. He wove about like someone walking with his eyes shut. “It doesn’t make sense,” I’d say at night. “You don’t grow backward.” Had he been injured somehow when he was out of our sight, banged his head, swallowed something poisonous? It was like searching for clues to a kidnapping. After visits to several doctors, we first heard the word “autism.” Later, it would be fine-tuned to “regressive autism,” now affecting roughly a third of children with the disorder. Unlike the kids born with it, this group seems typical until somewhere between 18 and 36 months — then they vanish. Some never get their speech back. Families stop watching those early videos, their child waving to the camera. Too painful. That child’s gone. In the year since his diagnosis, Owen’s only activity with his brother, Walt, is something they did before the autism struck: watching Disney movies. “The Little Mermaid,” “Beauty and the Beast,” “Aladdin” — it was a boom time for Disney — and also the old classics: “Dumbo,” “Fantasia,” “Pinocchio,” “Bambi.” They watch on a television bracketed to the wall in a high corner of our smallish bedroom in Georgetown. It is hard to know all the things going through the mind of our 6-year-old, Walt, about how his little brother, now nearly 4, is changing. They pile up pillows on our bed and sit close, Walt often with his arm around Owen’s shoulders, trying to hold him — and the shifting world — in place. © 2014 The New York Times Company
Link ID: 19341 - Posted: 03.10.2014
Alison Abbott A simple blood test has the potential to predict whether a healthy person will develop symptoms of dementia within two or three years. If larger studies uphold the results, the test could fill a major gap in strategies to combat brain degeneration, which is thought to show symptoms only at a stage when it too late to treat effectively. The test was identified in a preliminary study involving 525 people aged over 70. The work identified a set of ten lipid metabolites in blood plasma that distinguished with 90% accuracy between people who would remain cognitively healthy from those who would go on to show signs of cognitive impairment. “These findings are potentially very exciting,” says Simon Lovestone, a neuroscientist at the University of Oxford, UK, and a cordinator of a major European public-private partnership seekimg biomarkers for Alzheimer's. But he points out that only 28 participants developed symptoms similar to those of Alzheimer's disease during the latest work. “So the findings need to be confirmed in independent and larger studies.” There is not yet a good treatment for Alzheimer’s disease, which affects 35 million people worldwide. Several promising therapies have been tested in clinical trials over the last few years, but all have failed. However, those trials involved people who had already developed symptoms. Many neuroscientists fear that any benefits of a treatment would be missed in such a study, because it could be impossible to halt the disease once it has manifested. “We desperately need biomarkers which would allow patients to be identified — and recruited into trials — before their symptoms begin,” says Lovestone. © 2014 Nature Publishing Group,
Link ID: 19340 - Posted: 03.10.2014
By INNA GAISLER-SALOMON WE intuitively understand, and scientific studies confirm, that if a woman experiences stress during her pregnancy, it can affect the health of her baby. But what about stress that a woman experiences before getting pregnant — perhaps long before? It may seem unlikely that the effects of such stress could be directly transmitted to the child. After all, stress experienced before pregnancy is not part of a mother’s DNA, nor does it overlap with the nine months of fetal development. Nonetheless, it is undeniable that stress experienced during a person’s lifetime is often correlated with stress-related problems in that person’s offspring — and even in the offspring’s offspring. Perhaps the best-studied example is that of the children and grandchildren of Holocaust survivors. Research shows that survivors’ children have greater-than-average chances of having stress-related psychiatric illnesses like post-traumatic stress disorder, even without being exposed to higher levels of stress in their own lives. Similar correlations are found in other populations. Studies suggest that genocides in Rwanda, Nigeria, Cambodia, Armenia and the former Yugoslavia have brought about distinct psychopathological symptoms in the offspring of survivors. What explains this pattern? Does trauma lead to suboptimal parenting, which leads to abnormal behavior in children, which later affects their own parenting style? Or can you biologically inherit the effects of your parents’ stress, after all? It may be the latter. In a study that I, together with my colleagues Hiba Zaidan and Micah Leshem, recently published in the journal Biological Psychiatry, we found that a relatively mild form of stress in female rats, before pregnancy, affected their offspring in a way that appeared to be unrelated to parental care. © 2014 The New York Times Company
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.
By Tara Bahrampour, Alzheimer’s disease likely plays a much larger role in the deaths of older Americans than is reported, according to a new study that says the disease may be the third-leading cause of death in the United States. The Centers for Disease Control and Prevention lists Alzheimer’s as the sixth-leading cause of death, far below heart disease and cancer. But the new report, published Wednesday in the medical journal of the American Academy of Neurology, suggests that the current system of relying on death certificates for causes misses the complexity of dying for many older people and underestimates the impact of Alzheimer’s. While the CDC attributed about 84,000 deaths in 2010 to Alzheimer’s, the report estimated that number to be 503,400 among people 75 and older. That puts it in a close third place, behind heart disease and cancer, and well above chronic lung disease, stroke and accidents, which rank third, fourth and fifth. Alzheimer’s is somewhat of a sleeping giant compared with other leading killers that have received more funding over the years. While deaths from these diseases have been going down thanks to better treatment and prevention, the number of people suffering from Alzheimer’s is quickly rising and the disease is always fatal. More than 5 million people in the United States are estimated to have Alzheimer’s. With the aging of the baby-boom generation, this number is expected to nearly triple by 2050 if there are no significant medical breakthroughs, according to the Alzheimer’s Association. © 1996-2014 The Washington Post
Link ID: 19326 - Posted: 03.06.2014
Virginia Hughes When Brian Dias became a father last October, he was, like any new parent, mindful of the enormous responsibility that lay before him. From that moment on, every choice he made could affect his newborn son's physical and psychological development. But, unlike most new parents, Dias was also aware of the influence of his past experiences — not to mention those of his parents, his grandparents and beyond. Where one's ancestors lived, or how much they valued education, can clearly have effects that pass down through the generations. But what about the legacy of their health: whether they smoked, endured famine or fought in a war? As a postdoc in Kerry Ressler's laboratory at Emory University in Atlanta, Georgia, Dias had spent much of the two years before his son's birth studying these kinds of questions in mice. Specifically, he looked at how fear associated with a particular smell affects the animals and leaves an imprint on the brains of their descendants. Dias had been exposing male mice to acetophenone — a chemical with a sweet, almond-like smell — and then giving them a mild foot shock. After being exposed to this treatment five times a day for three days, the mice became reliably fearful, freezing in the presence of acetophenone even when they received no shock. Ten days later, Dias allowed the mice to mate with unexposed females. When their young grew up, many of the animals were more sensitive to acetophenone than to other odours, and more likely to be startled by an unexpected noise during exposure to the smell. Their offspring — the 'grandchildren' of the mice trained to fear the smell — were also jumpier in the presence of acetophenone. What's more, all three generations had larger-than-normal 'M71 glomeruli', structures where acetophenone-sensitive neurons in the nose connect with neurons in the olfactory bulb. In the January issue of Nature Neuroscience1, Dias and Ressler suggested that this hereditary transmission of environmental information was the result of epigenetics — chemical changes to the genome that affect how DNA is packaged and expressed without altering its sequence. © 2014 Nature Publishing Group,
|By Roni Jacobson Modern antipsychotic drugs are increasingly prescribed to children and adolescents diagnosed with a broad variety of ailments. The drugs help to alleviate symptoms in some disorders, such as schizophrenia and bipolar disorder, but in others their effectiveness is questionable. Yet off-label prescribing is on the rise, especially in children receiving public assistance and Medicaid. Psychotic disorders typically arise in adulthood and affect only a small proportion of children and adolescents. Off-label prescriptions, however, most often target aggressive and disruptive behaviors associated with attention-deficit hyperactivity disorder (ADHD). “What's really concerning now is that a lot of this prescription is occurring in the face of emerging evidence that there are significant adverse effects that may be worse in youth than in adults,” says David Rubin, a general pediatrician and co-director of PolicyLab at Children's Hospital of Philadelphia. Here we review the evidence for the effectiveness of antipsychotic medications commonly prescribed for five childhood conditions. But do the benefits outweigh the risks? Schizophrenia Evidence from several randomized controlled trials conducted in the past 10 years strongly suggests that antipsychotics are an effective treatment for youths with schizophrenia. Indeed, the FDA has approved five medications—risperidone, aripiprazole, olanzapine, quetiapine and paliperidone—for use in adolescents aged 13 to 17. Bipolar Disorder Recent research indicates that antipsychotics may hasten the resolution of manic and mixed episodes in children with bipolar disorder and increase the likelihood that the illness will go into remission. The FDA has approved the same set of drugs for 10- to 17-year-olds with bipolar disorder as it has for youths with schizophrenia, with the exception of paliperidone. © 2014 Scientific American
The teenager's brain has a lot of developing to do: It must transform from the brain of a child into the brain of an adult. Some researchers worry how marijuana might affect that crucial process. "Actually, in childhood our brain is larger," says , director of the brain imaging and neuropsychology lab at University of Wisconsin, Milwaukee. "Then, during the teenage years, our brain is getting rid of those connections that weren't really used, and it prunes back. "It actually makes the brain faster and more efficient." The streamlining process ultimately helps the brain make judgments, think critically and remember what it has learned. Lisdahl says it's a mistake for teenagers to use cannabis. "It's the absolute worst time," she says, because the mind-altering drug can disrupt development. Think of the teen years, she says, as the "last golden opportunity to make the brain as healthy and smart as possible." Lisdahl points to a growing number of that show regular marijuana use — once a week or more — actually changes the structure of the teenage brain, specifically in areas dealing with memory and problem solving. That can affect cognition and academic performance, she says. "And, indeed, we see, if we look at actual grades, that chronic marijuana-using teens do have, on average, one grade point lower than their matched peers that don't smoke pot," Lisdahl says. ©2014 NPR
By ANDREW POLLACK In the late 1980s, scientists at Osaka University in Japan noticed unusual repeated DNA sequences next to a gene they were studying in a common bacterium. They mentioned them in the final paragraph of a paper: “The biological significance of these sequences is not known.” Now their significance is known, and it has set off a scientific frenzy. The sequences, it turns out, are part of a sophisticated immune system that bacteria use to fight viruses. And that system, whose very existence was unknown until about seven years ago, may provide scientists with unprecedented power to rewrite the code of life. In the past year or so, researchers have discovered that the bacterial system can be harnessed to make precise changes to the DNA of humans, as well as other animals and plants. This means a genome can be edited, much as a writer might change words or fix spelling errors. It allows “customizing the genome of any cell or any species at will,” said Charles Gersbach, an assistant professor of biomedical engineering at Duke University. Already the molecular system, known as Crispr, is being used to make genetically engineered laboratory animals more easily than could be done before, with changes in multiple genes. Scientists in China recently made monkeys with changes in two genes. Scientists hope Crispr might also be used for genomic surgery, as it were, to correct errant genes that cause disease. Working in a laboratory — not, as yet, in actual humans — researchers at the Hubrecht Institute in the Netherlands showed they could fix a mutation that causes cystic fibrosis. But even as it is stirring excitement, Crispr is raising profound questions. Like other technologies that once wowed scientists — like gene therapy, stem cells and RNA interference — it will undoubtedly encounter setbacks before it can be used to help patients. © 2014 The New York Times Company
Keyword: Genes & Behavior
Link ID: 19317 - Posted: 03.04.2014
by Laura Sanders It truly pains me to bring you tired parents another round of “Is this bad for my baby?” But this week, a new study suggests that some white noise machines designed for babies can produce harmful amounts of sound. Before you despair about trashing your baby’s hearing, please keep in mind that like any study, the results are limited in what they can actually claim. And this one is no exception. I learned the power of white noise when Baby V and I ventured out to meet some new mamas for lunch. As I frantically tried to reverse the ensuing meltdown, another mom came over with her phone. “Try this,” she said as she held up her phone and blasted white noise. Lo and behold, her black magic worked. Instantly, Baby V snapped to attention, stopped screaming and stared wide-eyed at the dark wizardry that is the White Noise Lite app. Since then, I learned that when all else failed, the oscillating fan setting could occasionally jolt Baby V out of a screamfest. In general, I didn’t leave the noise on for long. It was annoying, and more importantly, it stopped working after the novelty wore off. But lots of parents do rely on white noise to soothe their babies and help them sleep through the night. These machines are recommended on top parenting websites by top pediatricians, parenting bloggers and, most convincingly, all of the other parents you know. Use liberally, the Internet experts recommend. To reap the benefits, white noise machines should be played all night long for at least the entire first year, many people think. And don’t be shy: The noise should be louder than you think. © Society for Science & the Public 2000 - 2013
by Megan Gannon, Live Science News Editor Never before seen in biology, a state of matter called "disordered hyperuniformity" has been discovered in the eye of a chicken. This arrangement of particles appears disorganized over small distances but has a hidden order that allows material to behave like both a crystal and a liquid. The discovery came as researchers were studying cones, tiny light-sensitive cells that allow for the perception of color, in the eyes of chickens. For chickens and other birds that are most active during the daytime, these photoreceptors come in four different color varieties — violet, blue, green and red — and a fifth type for detecting light levels, researchers say. Each type of cone is a different size. These cells are crammed into a single tissue layer on the retina. Many animals have cones arranged in an obvious pattern. Insect cones, for example, are laid out in a hexagonal scheme. The cones in chicken eyes, meanwhile, appear to be in disarray. But researchers who created a computer model to mimic the arrangement of chicken cones discovered a surprisingly tidy configuration. Around each cone is a so-called exclusion region that bars other cones of the same variety from getting too close. This means each cone type has its own uniform arrangement, but the five different patterns of the five different cone types are layered on top of each other in a disorderly way, the researchers say. © 2014 Discovery Communications, LLC.
by Clare Wilson More genetic mutations may be needed to give rise to autism in girls than in boys. The finding supports the notion that the female brain is somehow protected against autism, and this may in turn explain why four times as many males have autism than females. Although some cases of autism are associated with one mutation, most are thought to involve several genetic abnormalities. In the past few years, hundreds of mutations have been discovered that can make people more vulnerable to the condition. To see if the mutations affect men and women differently, Sébastien Jacquemont at the University Hospital of Lausanne in Switzerland and colleagues measured the frequency of two different kinds of mutation in 762 families that had a child with autism. Among the children with autism, one class of mutation known as a copy number variation – deletions or duplications of a large chunk of genetic material – was three times more common in girls than in boys. The team also found that substitutions of a single letter of DNA were about one-third more common in affected girls. Jacquemont says this suggests it takes more mutations for autism to arise in girls than in boys. "Females function a lot better than males with similar mutations," he says. The results reflect the "shielding" effect of being female, he says. "There's something that's protecting [their] brain development." A larger, as yet unpublished, study of about 2400 people with autism, conducted as part of the Autism Genome Project - an attempt to sequence the whole genome of 10,000 individuals affected by the condition – has produced similar results, says Joseph Buxbaum of Mount Sinai Hospital in New York. © Copyright Reed Business Information Ltd.
Brendan Borrell Scientists can now take snapshots of where and how thousands of genes are expressed in intact tissue samples, ranging from a slice of a human brain to the embryo of a fly. The technique, reported today in Science1, can turn a microscope slide into a tool for creating data-rich, three-dimensional maps of how cells interact with one another — a key to understanding the origins of diseases such as cancer. The methodology also has broader applications, enabling researchers to create, for instance, unique molecular ‘barcodes’ to trace connections between cells in the brain, a stated goal of the US National Institutes of Health's Human Connectome Project. Previously, molecular biologists had a limited spatial view of gene expression, the process by which a stretch of double-stranded DNA is turned into single-stranded RNAs, which can in turn be translated into protein products. Researchers could either grind up a hunk of tissue and catalogue all the RNAs they found there, or use fluorescent markers to track the expression of up to 30 RNAs inside each cell of a tissue sample. The latest technique maps up to thousands of RNAs. Mapping the matrix In a proof-of-principle study, molecular biologist George Church of Harvard Medical School in Boston, Massachusetts, and his colleagues scratched a layer of cultured connective-tissue cells and sequenced the RNA of cells that migrated to the wound during the healing process. Out of 6,880 genes sequenced, the researchers identified 12 that showed changes in gene expression, including eight that were known to be involved in cell migration but had not been studied in wound healing, the researchers say. “This verifies that the technique could be used to do rapidly what has taken scientists years of looking at gene products one by one,” says Robert Singer, a molecular cell biologist at Albert Einstein College of Medicine in New York, who was not involved in the study. © 2014 Nature Publishing Group,
By STEPHEN P. HINSHAW and RICHARD M. SCHEFFLER BERKELEY, Calif. — THE writing is on the chalkboard. Over the next few years, America can count on a major expansion of early childhood education. We embrace this trend, but as health policy researchers, we want to raise a major caveat: Unless we’re careful, today’s preschool bandwagon could lead straight to an epidemic of 4- and 5-year-olds wrongfully being told that they have attention deficit hyperactivity disorder. Introducing millions of 3- to 5-year-olds to classrooms and preacademic demands means that many more distracted kids will undoubtedly catch the attention of their teachers. Sure, many children this age are already in preschool, but making the movement universal and embedding transitional-K programs in public schools is bound to increase the pressure. We’re all for high standards, but danger lurks. The American Academy of Pediatrics now endorses the idea that the diagnosis of A.D.H.D. can and should begin at age 4, before problems accumulate. In fact, Adderall and other stimulants are approved for treatment of attentional issues in children as young as 3. Early intervention for children with A.D.H.D. could provide great relief. Children who go untreated have major difficulties in school and with their peers, and they have higher-than-normal rates of accidents and physical injuries. The problem is that millions of American children have been labeled with A.D.H.D. when they don’t truly have it. Our research has revealed a worrisome parallel between our nation’s increasing push for academic achievement and increased school accountability — and skyrocketing A.D.H.D. diagnoses, particularly for the nation’s poorest children. © 2014 The New York Times Company
Ian Sample, science correspondent Children born to fathers over the age of 45 are at greater risk of developing psychiatric problems and more likely to struggle at school, according to the findings of a large-scale study. The research found that children with older fathers were more often diagnosed with disorders such as autism, psychosis, attention deficit hyperactivity disorder (ADHD), schizophrenia and bipolar disorder. They also reported more drug abuse and suicide attempts, researchers said. The children's difficulties seemed to affect school performance, leading to worse grades at the age of 15 and fewer years in education overall. "We were shocked when we saw the comparisons," said Brian D'Onofrio, the first author of the study at Indiana University in the US. But he added that it was impossible to be sure that older age was to blame for the problems. Scientists have reported links between fathers' age and children's cognitive performance and health before but this study suggests the risks may be more serious than previously thought. The increased risks might be caused by genetic mutations that build up in sperm as men age. Researchers at Indiana University and the Karolinska Institute in Stockholm studied medical and educational records of more than 2.6 million babies born to 1.4 million men. The group amounted to nearly 90% of births in Sweden from 1973 and 2001. Using the records, the scientists added up diagnoses for psychiatric disorders and educational achievements and compared the figures for children born to fathers of different ages. © 2014 Guardian News and Media Limited
by Emily Sohn Immediately after birth on many dairy farms, baby cows are separated from their mothers and housed in their own pens to protect them from getting sick. Two months later, they join the herd. But early-life isolation may be depriving baby cows of the opportunity to reach their full potential, found a new study. Compared to calves raised in pairs, isolated calves were much slower to learn new things and had a harder time adapting to changes in their environment. Aside from animal welfare concerns, the new findings suggest that dairy farmers have long been overlooking the brain development of their cows by depriving them of social interaction in their early weeks. “Imagine I said that instead of sending your child to kindergarten, I could put him in the classroom one-on-one with the teacher and all the same resources,” said Daniel Weary, a professor of animal welfare and dairy science at the University of British Columbia in Vancouver. “But at the end of the day, if we found that individuals in this system were showing cognitive deficits in relation to other individuals, we would feel bad about that.” For cows, he said, “it means we’re not keeping these animals in an environment that allows them to be what they can be and should be.” © 2014 Discovery Communications, LLC
Keyword: Development of the Brain
Link ID: 19298 - Posted: 02.27.2014
On 24 February, Uganda’s president, Yoweri Museveni, signed a draconian Anti-Homosexuality Bill into law, after 2 months of declining to do so. Science, he says, changed his mind—in particular, the findings of a special scientific committee his Health Ministry had appointed earlier in the month. “Their unanimous conclusion was that homosexuality, contrary to my earlier thinking, was behavioural and not genetic,” Museveni wrote to President Barack Obama on 18 February, in response to Obama’s pleas that he not sign the bill. “It was learnt and could be unlearnt.” But some scientists on the committee are crying foul, saying that Museveni and his ruling party—Uganda’s National Resistance Movement (NRM)—misrepresented their findings. “They misquoted our report,” says Paul Bangirana, a clinical psychologist at Makerere University in Kampala. “The report does not state anywhere that homosexuality is not genetic, and we did not say that it could be unlearnt.” Two other committee members have now resigned to protest the use of their report to justify the harsh legislation, which mandates life imprisonment for “aggravated homosexuality,” such as sexual acts with a minor, and prison terms of 7 to 14 years for attempted and actual homosexual acts, respectively. The law was first introduced into Uganda’s Parliament in 2009, but withdrawn after widespread objections to provisions that could have included the death penalty. As he signed the new version, passed by Parliament last 20 December, Museveni claimed that “mercenaries” were recruiting young people into gay activities. © 2014 American Association for the Advancement of Science
|By Jenni Laidman People born with Down syndrome have always been considered to be incurably developmentally delayed—until now. In the past few years a number of laboratories have uncovered critical drug targets within disabled chemical pathways in the brain that might be restored with medication. At least two clinical trials are currently studying the effects of such treatments on people with Down syndrome. Now geneticist Roger Reeves of Johns Hopkins University may have stumbled on another drug target—this one with the potential to correct the learning and memory deficits so central to the condition. Down syndrome occurs in about one in 1,000 births annually worldwide. It arises from an extra copy of chromosome 21 and the overexpression of each of the 300 to 500 genes the chromosome carries. “If you go back even as recently as 2004, researchers didn't have much of a clue about the mechanisms involved in this developmental disability,” says Michael Harpold, chief scientific officer with the Down Syndrome Research and Treatment Foundation. But all that has changed. “In the past six or seven years there have been several breakthroughs—and ‘breakthroughs’ is not by any means too big a word—in understanding the neurochemistry in Down syndrome,” Reeves says. This improved knowledge base has led to a series of discoveries with therapeutic promise, including the latest by Reeves. He and his team were attempting to restore the size of the cerebellum in mice engineered to show the hallmarks of Down syndrome. The cerebellum lies at the base of the brain and controls motor functions, motor learning and balance. In people with Down syndrome and in the Down mouse model the cerebellum is about 40 percent smaller than normal. By restoring its size, Reeves hoped to gain a clearer picture of the developmental processes that lead to anomalies in a brain with Down syndrome. © 2014 Scientific American
by Nathan Seppa Women who take acetaminophen during pregnancy are more likely to have a child with attention-deficit/hyperactivity disorder than are women who don’t, according to an analysis of nearly 41,000 pairs of mothers and children in a Danish birth registry. Researchers found that more than half of the women, who gave birth between 1996 and 2002, had used the pain reliever during pregnancy. Calls to the women when the children were 7 years old revealed that children whose moms used any acetaminophen during pregnancy were 37 percent more apt to be diagnosed with ADHD or a related disorder than children whose moms didn’t use the drug. If the women used it in all three trimesters, the apparent risk for offspring was 61 percent higher than for children whose mothers didn’t use the drug. Out of nearly 41,000 children, fewer than 1,000 were diagnosed with ADHD and related disorders. The data establish an association and not cause and effect. But the researchers note that acetaminophen, also sold as Tylenol or Panadol, can cross the placental barrier and may affect hormones in a fetus. Citations Z. Liew et al. Acetaminophen use during pregnancy, behavioral problems, and hyperkinetic disorders. JAMA Pediatrics. Online February 24, 2014. doi:10.1001/jamapediatrics.2013.4914. © Society for Science & the Public 2000 - 2013.