No treatment is more emblematic of the world of alternative therapies for autism than chelation. The influential autism recovery group, Defeat Autism Now, calls removing metals from the body "one of the most beneficial treatments for autism and related disorders." Chelation is one of the highest-rated treatments on the parent survey of the nonprofit Autism Research Institute, the parent organization of Defeat Autism Now.
Parents trade stories and advice about chelation on large Internet groups. One Yahoo group has more than 8,000 members. The treatment takes many forms, including creams for the skin, capsules, suppositories and intravenous infusions of powerful medicines usually reserved for people with severe metal poisoning.
Families often embark on this course after seeing test results that make children with autism look like they spend their days playing in smelting plants.
A boy named Jordan King was chelated after his lab reports showed apparently high levels of mercury and tin, according to testimony at a special vaccine court formed by the government to address claims from people who think vaccines caused them harm.
It was "shocking" to see tin turn up, testified Dr. Robert Rust, a chaired professor of neurology at University of Virginia. "It's seen almost exclusively in people who spend their careers for long periods of time working with tin," he said.
In fact, Jordan's troubling results were based on a lab test that is common in the world of alternative autism treatments and is practically guaranteed to give incredible results.
A child is given a chelating drug that provokes the body to excrete some of the metals that nearly everybody -- healthy or not -- has in the body in trace amounts. Those metals are excreted in urine, which is sent to a lab offering these tests.
Nobody knows what normal results of this test would look like, toxicologists say. But the lab sends back charts that show alarming peaks of metals graphed against a reference range that was calculated for people who had never been given a chelator.
"That is exactly the wrong way to do it," said Dr. Carl R. Baum, director of the Center for Children's Environmental Toxicology at Yale-New Haven Children's Hospital.
With Jordan and another child whose case was examined in vaccine court, "there was absolutely no reason to chelate them for any mercury-related reason," testified Dr. Jeffrey Brent of the University of Colorado, Denver, former president of the American Academy of Clinical Toxicology.
Alarmed by the rise in the use of this test to justify chelation, the American College of Medical Toxicology this summer criticized its use as "fraught with many misunderstandings, pitfalls and risks."
Toxicologist William Shaw, lab director of the Great Plains Laboratory in Lenexa, Kan., and Jane Johnson, executive director of Defeat Autism Now, said the labs are identifying real problems and they have seen children benefit from chelation.
"Our only bedrock here is the observation by clinicians and parents that their children get better when they are given agents which are known to remove heavy metals from the body," Johnson wrote in an e-mail.
But such anecdotal evidence is "at best good for generating hypotheses," Baum said. "Where's their control group? Their randomized controlled trial?"
Chelation's popularity as a treatment for autism is driven by the unproved idea that the disorder is tied to accumulation of heavy metals in the body. Mercury, once common in vaccines as part of a preservative called thimerosal, is often pegged as the culprit.
Yet the federally chartered Institute of Medicine reported in 2004 that a review of dozens of studies had failed to show a link between vaccines, thimerosal and autism. Subsequent studies also found no connection. After thimerosal was removed from childhood vaccines except for some flu shots, autism diagnoses continued to rise.
Last spring, after hearing hundreds of hours of testimony, three "special masters" presiding over vaccine court ruled conclusively that they found the argument that the measles-mumps-rubella vaccine and thimerosal cause autism unpersuasive.
Even when tests show normal or low levels of metals, doctors who support chelation as an autism therapy sometimes take the results as proof that the child is poisoned. They hypothesize that the child cannot excrete metals, which is why they do not show up in tests.
Colten Snyder, another child whose case was evaluated in vaccine court, underwent chelation after tests on his blood and hair over six years came back normal for mercury, court records state.
Given that the boy was immunized with vaccines containing thimerosal, "his hair mercury was exceptionally low," said his physician, Dr. J. Jeff Bradstreet of Florida. "That's pathological."
Colten went "berserk" after being given a chelator, according to a nurse whose notes were cited in court records. He also had incontinence, night sweats, headaches and back pain. Bradstreet testified that the boy did not do well with chelation but later said it is "impossible to know" what caused the problems.
In her decision, special master Denise Vowell criticized Bradstreet: "The more disturbing question is why chelation was performed at all, in view of the normal levels of mercury found in the hair, blood and urine, its apparent lack of efficacy in treating Colten's symptoms and the adverse side effects it apparently caused."
Pediatric toxicology experts say that all chelation drugs carry risks -- even when used to treat severely lead-poisoned children. Treatment with the medication is carefully monitored, as some drugs can dangerously deplete the body of essential metals, toxicologists said.
When rats with no lead exposure were treated with succimer, a common chelator given to children with autism, the animals showed lasting impairments of cognitive function and emotional regulation, said the study's lead researcher, Barbara Strupp at Cornell University.
She said that finding raises concerns about administering chelators to children with autism unless they clearly have elevated levels of heavy metals. "I was just astounded and concerned for these kids," she said.
After she learned that the National Institutes of Health planned to conduct a clinical trial of chelation in children with autism, she alerted the researchers to her findings. The study was later canceled.