Heavy metals may be implicated in autism 27 May 2006 From New Scientist Print Edition. Subscribe and get 4 free issues.
URINE samples from hundreds of French children have yielded evidence for a link between autism and exposure to heavy metals. If validated, the findings might mean some cases of autism could be treated with drugs that purge the body of heavy metals.
Samples from children with autism contained abnormally high levels of a family of proteins called porphyrins, which are precursors in the production of haem, the oxygen-carrying component in haemoglobin. Heavy metals block haem production, causing porphyrins to accumulate in urine. Concentrations of one molecule, coproporphyrin, were 2.6 times as high in urine from children with autism as in controls.
Autism is thought to have a number of unknown genetic and environmental causes. Richard Lathe of Pieta Research in Edinburgh, UK, says he has found one of these factors. "It's highly likely that heavy metals are responsible for childhood autistic disorder in a majority of cases," he claims. The study will appear in Toxicology and Applied Pharmacology.
Lathe says these porphyrin metabolites bind to receptors in the brain and have been linked with epilepsy and autism.
The researchers restored porphyrin concentrations to normal in 12 children by treating them with "chelation" drugs that mop up heavy metals and are then excreted. It is not yet known whether the children's symptoms have eased, but Lathe cites anecdotal reports suggesting the drugs might do some good.
From issue 2553 of New Scientist magazine, 27 May 2006, page 21
I'm confused. The explanation for the famous mercury-hair study was, "See, the controls have higher mercury content in their hair because they excrete better than autistics." This led to (or confirmed?) other studies regarding the APOe gene and it's link to detoxification of heavy metals. This all made a lot of sense to me.
But this new study seems to say the opposite. Am I missing something? Your comments are welcome.
UPDATE: No surprise, I was missing something. Something big. (It was late when I read and posted that.) Scott emailed me back this morning:
...read it again. It is not the mercury they are talking about that shows up in the urine. It is the protein that mercury and other metals in the body block if present. Since they are blocked by metals and unable to create hemoglobin which helps detox, they are excreted in the urine.
Heavy metals block haem production, causing porphyrins to accumulate in urine. Concentrations of one molecule, coproporphyrin, were 2.6 times as high in urine from children with autism as in controls.
Pat then added, "Yes, this type test is very definitive for metal poisoning."
Hmm...I'm sure the anti- anti-mercury/autism crusaders (AutismDiva, Orac, Kev, etc.) are busy setting phazers to "full debunk." They are anti any study that links mercury to autism, for various reasons. So be on the look out for the common attacks on the New Scientist ("it's a crap journal"), attacks on study funding, methodology, the urine test itself, the people who collected the urine, relatives who collected the urine, etc. Not that I'm saying that there couldn't be flaws in any of these areas, but innocent until proven guilty.