Researchers Pose More Autism Questions
WebMD News Archive
May 10, 2001 -- Autism, a childhood disorder characterized by profound developmental impediments in speech, learning, and socialization, could be related to a defect in the body's ability to process common metals such as zinc, copper, and aluminum, according to a new study presented at the annual meeting of the American Psychiatric Association.
A deficiency in a protein known as metallothionein, which helps to regulate minerals and metals in the human body, is highly prevalent in children with autism, say Anjum Usman, MD, and William J. Walsh, PhD, of the Pfeiffer/Health Research Institute in Naperville, Ill. The Institute specializes in nutritional treatment of behavior, mood, and learning disorders in children and adults.
"Metallothionein is a very important protein in our body that regulates the balance of metals and minerals in and out of cells," Usman tells WebMD. "It is important for the development of the brain, intestines, and the immune system. If you have a defect in that protein -- whether it's genetic or caused by an environmental insult [or stress] -- those areas will be affected."
Among other things, metallothionein helps to regulate the ratio of copper to zinc in human cells. Some of the features of autism -- problems with speech, socialization, eye contact, immune system and the stomach -- are similar to those in people who have a metallothionein defect, she says.
In the study, Usman and Walsh analyzed blood and urine in 503 children with autism and found that 99% had evidence of the metallothionein defect. "Compared to a normal population, children with autism had extremely elevated copper and zinc ratios," Usman tells WebMD. "We believe it may be due to a defect in this metallothionein protein affecting the body's ability detoxify metals and to handle slight insults [or stresses]."
If correct, the finding could lead to an early infant screening test for autism. And Usman tells WebMD it may be possible to treat symptoms of metallothionein defect with nutrients and antioxidants -- the natural substances that clear away the toxic elements left behind by the body's natural oxidation of cells.
But what is the connection between a metallothionein defect and autism?
"If there is a problem with metallothionein in the first two years or so life, the brain will not develop fully," she explains. "Speech would not develop properly, and that could be due to high copper."
Usman says any exposure to toxic elements that put a burden on the defective metallothionein system could cause or exacerbate problems related to autism.
Such exposures could include vaccines that contain high levels of copper and mercury, such as the hepatitis B vaccine, she says. "The metallothionein defect could lead to abnormal responses to vaccines containing mercury, aluminum or other toxic metals."
Any number of other environmental exposures, however, such as second-hand smoke or lead, could also contribute to symptoms in a person with a metallothionein defect, she says.