A new study sheds light on the mystery of autism and may point the way to a promising treatment. Some autistic children have a weakened ability to protect themselves from toxic metals in their bodies, a biochemist at the University of Arkansas for Medical Sciences has concluded. Such children have a severe deficiency of glutathione, the body's most important tool for detoxifying and excreting heavy metals such as mercury and lead, Dr Jill James reports in a peer-reviewed study published this month in the American Journal of Clinical Nutrition. Dr James' findings provide new ammunition for those who suspect that mercury-containing vaccines play a role in autism. The study, which involved 20 autistic children, also suggests a possible intervention for the disorder, which has no known cause or cure. In an attempt to correct their metabolic imbalance, Dr James gave eight of the participants supplements of folinic acid, a form of folic acid, and vitamin B12. Their glutathione measurements then improved. Elizabeth Mumper, an associate professor of clinical pediatrics at the University of Virginia Medical School, said she had given similar supplements to many autistic children and noticed a marked improvement in some. 'I don't mean to imply that I can cure autism, but for a subset the results can be dramatic,' Dr Mumper said. She and Dr James said they hoped other researchers would attempt to replicate their findings. Most researchers, including Dr James, say there is a strong genetic component to autism. Some also suspect that one or more environmental factors push genetically vulnerable children over the edge into autism.