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One of the studies also finds, for the first time, that oxytocin regulation in people with autism is partly controlled by epigenetic changes, which can turn genes on or off without altering the underlying code.
Oxytocin has been linked to autism for nearly two decades, and the hormone is already being doled out in several small clinical trials to treat the disorder. But the new reports are part of a growing wave of interest in the precise nature of its involvement.
“The field is really new,” says Sue Carter, professor of psychiatry at University of Illinois at Chicago, who was not involved in either new study.
Researchers have previously found significant associations between particular oxytocin-related variants and autism, but how these variants alter the hormone’s production or interact with other genes and developmental influences is unclear, Carter says. “At this point, we’re working with fragments of knowledge, but the fragments we have are remarkably consistent.”
A large clinical trial to test the first drug specifically designed to treat autism is under way at 12 sites across the United States.
Curemark, a 10-person drug research company based in Rye, New York, says the drug, CM-AT, helps children with autism digest proteins. This in turn allows the children to ingest essential amino acids from the proteins, and ultimately produce key brain signaling molecules, company officials say.
For decades, gastrointestinal (GI) issues in children with autism have been a hot topic of debate. Up to 70 percent of children with autism report having GI problems such as stomach pain or constipation, and 60 percent have food selectivity, according to a 2006 study. A highly publicized report last summer, however, found that most of those issues are no more common in children with autism than in healthy children.
Because of this conflicting evidence, as well as the mystery surrounding how CM-AT works, some autism experts are skeptical of Curemark’s claims. Seven independent scientists contacted for this article declined to comment on the trial, citing the dearth of published data and the controversial nature of the therapy’s premise.
Nevertheless, the U.S. Food and Drug Administration has approved the Phase III trial, intended to show that CM-AT improves both the core features of autism — communicative problems, social deficits and repetitive behaviors — as well as less common symptoms, such as digestive problems. Phase III trials are randomized and placebo-controlled, and are the final stage in the long road to regulatory approval.
Ten of the 12 trial sites have begun recruiting 3- to 8-year-old children with autism, and the company says it plans to enroll 170 children by July.
“This is a very big deal,” says pediatric chiropractor Joan Fallon, Curemark’s founder and chief executive officer. “It’s been many, many years of preparing and preparing and preparing, and now we’re there.”
Courtesy: U. of Washington Institute for Learning & Brain Sciences
In typical conversation, people speak at a rate of 250 milliseconds per syllable. So imagine how confusing it would be if you lagged behind — even if only by a fraction of a second.
That tiny delay may be what’s provoking the language problems in some children with autism.
Tim Roberts, a radiologist at the Children’s Hospital of Philadelphia, has been studying the phenomenon for the last decade. He uses magnetoencephalography, or MEG, the ‘hair dryer’ brain imaging method that uses magnetic fields to detect changes in brain activity on the order of 10 milliseconds or less.
Last week, his team reported that when listening to tones of different frequencies, children with autism give brain responses in their right hemispheres about 11 milliseconds slower than healthy controls do. In other, unpublished work, Roberts found a much longer delay — about 50 milliseconds — when children with the disorder process speech sounds, such as ‘ah’ or ‘ou’.
The average age of children in the study was 10 years. If the findings are similar in babies and toddlers with autism, Roberts says this lag measurement may be a reliable marker for diagnosing the disorder, even before other symptoms appear.
MEG would be particularly useful for young children because it’s non-invasive and doesn’t require them to perform a difficult task. On the downside, a MEG scan isn’t a realistic option for the majority of children with autism — there are only about 100 machines worldwide.
Children with autism have gastrointestinal problems, and special diets can help resolve these issues.
That idea is all but accepted as fact by parents, advocates and scientists alike. Many parents of children with autism report that the children have frequent stomachaches, constipation or acid reflux, and some attribute these to problems digesting gluten or dairy proteins.
In a review published Monday in Pediatrics, a large and diverse group of pediatric experts states unequivocally that there is no evidence to support the idea of autism-specific gut problems or of a so-called ‘leaky gut’ that doesn’t allow children with the disorder to properly digest nutrients.
The journal periodically publishes these consensus reports to try to address controversial issues in an objective way, and to help guide physicians in making good diagnoses and treatment plans. For this one, the panel included 28 clinicians with expertise in, among other things, child psychiatry, epidemiology, allergies, nutrition and pain.
The group’s ultimate recommendation is to treat gut problems in children with autism as you would treat them in any child. The only difference between the two groups may be in how the child responds: a stomachache may make a typical child a bit cranky, but provoke more severe outbursts in a child with autism.
The panel doesn’t rule out the possibility that future research might uncover autism-specific gut problems, pointing out that studies to date are somewhat difficult to interpret. For instance, one study estimates that more than 70 percent of children with autism have gastrointestinal troubles, whereas another pegs that number at a paltry 9 percent.
The panel recommends that studies focus on more precisely calculating this prevalence, rather than on investigating gut issues as root causes of the disorder rigorously designed studies to more precisely calculate this prevalence and to investigate gut issues as root causes of the disorder.
In the meantime, the experts say it’s best to avoid the special diets pushed by the alternative medicine community. They have shown no benefit to children with autism, they note, and, if taken to extremes, could result in harmful malnutrition.
(Edited 1/9, thanks to comment from MJ)
Paintings of trees with spindly brown branches and plump green leaves cover the walls. Books, plastic cars and coloring books spill out across the carpeted floor and fill several plastic bins.
The children who come here are as young as 3 months on their first visit, and return every few months to participate in a battery of tests of their social behavior and perceptual processing — the brain’s response to non-social stimuli, such as looking at an ordinary object.
About one in four of these children is particularly interesting to the researchers: They are the younger siblings of children with autism, and are much more likely to develop the disorder than are those without a family history of it. Over the past few years, scientists have gathered heaps of behavioral data from these so-called ‘baby sibs’, but the Baby Lab is among the first to look for distinct signatures of brain activity.
Researchers from Signature Genomics, a private clinical genetic testing company in Spokane, Washington, have found, for instance, that many children with autism inherit deletions in the 16p11.2 chromosomal region — famously linked to autism — from healthy parents with no sign of the disorder.
The findings debunk previous hype that any one variant is crucial for a particular disorder, the researchers say.
A pathway involved in language development is increasingly proving to be important in autism, suggest a series of new studies on cellular and behavioral aspects of the disorder.
Reports published in the last year, as well as preliminary data revealed last week at the Society for Neuroscience meeting in Chicago add heft to the idea that the pathway may cause the language and other problems associated with autism.
In 1990, a letter to Nature described a large, three-generation family from London whose members had severe and distinct deficits in applying grammatical rules, and suggested “one dominant gene” as the cause. A decade later, geneticists screening the family pinpointed a gene — FOXP2, on chromosome 7 — that is mutated in family members with language impairment.
FOXP2 codes for a protein that regulates the expression of other genes. Last year, an international group of scientists identified one of its targets, contactin-associated protein-like 2 (CNTNAP2). They also found that certain common variants of CNTNAP2 tend to crop up in people with specific language impairment, a developmental disorder.
CNTNAP2 was an exciting find because three independent teams had recently published that common variants of the gene up the risk of developing autism.
“I think the evidence now that CNTNAP2 is involved [in autism] is quite good,” says leader of one of the teams, Aravinda Chakravarti, professor at the McKusick Nathans Institute of Genetic Medicine at Johns Hopkins University. “We’re now interested in finding the molecular basis of this.”
Because these defects are seen during a critical period of learning, they could prevent developing brain cells from linking up to appropriate brain circuits, says lead investigator Carlos Portera-Cailliau, assistant professor of neurology and neurobiology at the University of California in Los Angeles. “This presumably has serious consequences for the ability of these mice to learn,” he says.
The researchers studied the gene expression profiles of five brains and found two distinct types: one that preferentially expresses genes controlling immune regulation, and another expressing those related to changes at synapses, the junctions between neurons.
Intriguingly, few genes are over-expressed in both types of brains as compared with healthy controls, which may speak to the heterogeneity of the disorder, says lead investigator John Allman, professor of biology at the California Institute of Technology. “There may be several routes to autism.”
People who lack a corpus callosum (right) have trouble identifying fearful (top) and angry (bottom) faces compared with controls (left). The colors indicate amount of time spent looking at the region, with red being the longest.
People born without the large bundle of nerve fibers that bridges the brain’s hemispheres have trouble identifying fearful faces, and don’t look preferentially at others’ eyes to perform this task, according to research presented Sunday at the Society for Neuroscience meeting in Chicago.
Because similar face-processing patterns are seen in people with autism, the new work bolsters the evolving, 20-year-old theory that autism stems from impaired long-range connections in the brain, says lead investigator Lynn Paul.
The corpus callosum is the largest and fastest conduit in the brain, containing an estimated 250 million axons that connect the language and symbolic reasoning of the left side of the brain with the spatial manipulation, and audio-visual processing generally controlled by the right.
Paul studies agenesis of the corpus callosum (AgCC), a congenital disorder in which this important structure does not develop. About 1 in every 3,000 people are born this way, and many of them have average intelligence, walk and talk normally, and have families.
What these people usually can’t do well is rapidly integrate information between the two sides of the brain, which is particularly important in self-awareness, making social judgments, and carrying out live social interactions. These deficits become most apparent around age 8 or 9, when social interactions become much more complicated.
