Researchers have taken significant steps towards determining the mysterious causes of autism, with the discovery that two-thirds of autistic people have a genetic variant that influences how neurons connect with each other. An additional study found a link between autism and small “mistakes” in another DNA segment involved with cell communication. Both reports add weight to the idea that autism is related to problems with the way brain cells connect [Los Angeles Times].
The two studies were made possible by improved technology that allowed researchers to compare the genomes of thousands of autistic people to those of thousands of people without the disorder, looking for genetic differences between the two groups. Previous studies that have identified several genes that are implicated in autism, but … they are extremely rare and account for a very small proportion of autism [New Scientist]. The two studies, both published online by Nature, won’t lead immediately to new treatments, but they open up important new avenues of research.
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A controversial autism treatment has gotten a credibility boost. The first rigorously scientific study of hyperbaric oxygen treatment, in which autistic children breathe in extra oxygen inside a pressurized chamber, found that children who received the treatment showed improvement in social interactions, although researchers note that the small study didn’t examine whether the treatment had long-term effects.
Study leader Dan Rossignol says the use of hyperbaric therapy for autism has been gaining popularity in the US where parents can buy their own hyperbaric chamber if they have a spare $14-17,000 [BBC News]. Other parents take their children to clinics for treatments that usually cost between $120 and $150 per session, and which typically aren’t covered by insurance providers. Rossignol says he expects the findings to generate controversy, and notes that he too was initially very sceptical of the idea but was prompted to do more research after the treatment showed benefits for his two sons who have autism. “We’re certainly not talking about a cure, we’re talking about improvements in behaviour, improving certain functions and quality of life” [BBC News].
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Although the vast majority of the scientific establishment has loudly declared for years that there is no link between autism and childhood vaccinations, some parents with autistic children have persisted in making the claim, and even brought the matter to a special federal court. Now, the judges appointed to rule on the first cases have added their voices to those of the scientists, stating that there is no such link. One of the officials, George Hastings, said the parents had “been misled by physicians who are guilty, in my view, of gross medical misjudgment.” Hastings said that he was deeply moved by the suffering autism imposed on families … but that “the evidence advanced by the petitioners has fallen far short of demonstrating . . . a link” [Washington Post].
The parents had brought their cases to the National Vaccine Injury Compensation Program, which was set up to compensate the very few people who suffer serious side effects from vaccines. Rather than have these victims sue vaccine makers in regular court — potentially putting the manufacturers out of business and jeopardizing a major component of the country’s public health infrastructure — the court set up a “no-fault” system that required victims to prove to a special master only that vaccines harmed them, and not that anyone intentionally caused the harm [Washington Post]. In 2001, parents of children with autism began filing petitions with the program asking for compensation. Of the 12,850 cases ever filed through the program, about 5,535 represented autism cases [AP].
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When researcher Julian Asher goes to the symphony, he gets a sensory extravaganza. “When I hear a violin, I see something like a rich red wine,” says Asher…. “A cello is more like honey” [New Scientist]. Asher has a condition called synesthesia in which sensory information gets mixed in the brain; in Asher’s particular form, auditory-visual synesthesia, sounds cause him to see colors. Now, a study led by Asher may have uncovered the genetic source of the condition, which synesthetes say can be both a blessing and a curse.
The researchers collected DNA samples from 196 people who had auditory-visual synesthesia running in their families, they explain in the American Journal of Human Genetics [subscription required]. Asher expected to find a single gene associated with the condition, but scanning the genomes revealed that it was linked to four distinct regions, on chromosomes 2, 5, 6, and 12.
The region that was most strongly linked to synesthesia was an area on chromosome 2 that has also been strongly linked to autism. That doesn’t mean that the two conditions are related, per se, explained Ed Hubbard, a cognitive neuroscientist…. Instead, the common gene or genes are likely “more generally involved in how the brain gets built.” The study also pulled out a region on chromosome 6 that contains genes linked to dyslexia — especially interesting, “seeing as phonemes [the units of sound in language] and letters are two of the strongest synesthetic triggers,” Asher said [The Scientist].
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A federal health agency has dropped plans for a controversial autism study, pleasing many scientists but disappointing some families with autistic children. The study would have tested a treatment called chelation, which removes heavy metals from the body and is used to treat lead poisoning. Its use as an autism treatment is based on the fringe theory that mercury in vaccines triggers autism — a theory never proved and rejected by mainstream science. Mercury hasn’t been in childhood vaccines since 2001, except for certain flu shots [AP].
The National Institute of Mental Health had previously said that if the study proved that chelation therapy had no effect, if would have finally dismissed the “anecdotal reports” that the treatment is effective. But safety concerns based on recent animal studies apparently deterred the institute from continuing with the study. “NIMH has decided that resources are better directed at this time to testing other potential therapies for autism spectrum disorders, and is not pursuing the additional review required to begin the study,” the institute said [Reuters].
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Researchers have discovered five new genetic defects that are linked to autism and that appear to share a common function: They’re associated with learning, and are part of a network that allows a child’s brain to build new connections in response to experience [Web MD].
Symptoms of autism typically emerge during the first five years of life — a period when a child normally picks up language, social skills and many other new abilities. Scientists call this kind of growth “experience-dependent learning,” and researchers know that it is associated with enormous changes in brain circuitry. At least 300 genes switch on and off to regulate experience-dependent learning [Time]. Researchers say that the newly identified genes, as well as others already linked to autism, may fail to turn on during this crucial developmental stage, preventing children from learning those social skills and abilities.
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