From Albert Donnay
Exposure to heavy metals is only one possible explanation for the elevated levels of urinary porphyrins found in French children with autism (27 May, p 21). Many other toxic chemicals, such as hexacholorobenzene, drugs such as anabolic steroids, and even chronic exposure to low levels of carbon monoxide (CO) have been found to increase urinary porphyrins, in particular coproporphyrins.
The possible role of CO in autism is particularly significant, since CO poisoning is known to cause similar chronic symptoms, and there is strong interest in hyperbaric oxygen therapy, the gold standard of treatment for CO poisoning, as a treatment for autism.
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