Autism: Looking for answers to a growing problem
Tuesday, February 17, 2004 (23:02:48)

Posted by Sylvia

Courier Press 16/02/2004

By Joan Lowy

It's one of the worst nightmares a parent can imagine - without warning, a child is abducted from his bed in the middle of the night, never to return.

Now, imagine that instead of taking the whole child, only his mind is stolen and his body - the hollow shell of his being - is left behind

That's the way parents of children with autism feel, said Hollywood producer Jon Shestack, whose 11-year-old son is autistic.

"If one in every 250 children in America were actually being abducted, that would be a national emergency," Shestack said. "But that is what is happening with autism, and it is a national emergency."

Autism - a devastating brain disorder that usually appears before age 3 and affects a child's ability to communicate, form relationships and respond to the world around him - used to be rare, but is now at least as prevalent as childhood cancer or diabetes. Although the disorder takes many forms, in most cases children seem to withdraw into their own worlds.

In the 1970s, autism was estimated to have affected about one in 2,500 to 5,000 children. Studies show it occurs today in one in 150 to 500 children. About 1.5 million Americans are autistic. Boys are affected three to four times as often as girls.

Although the phenomenon has been reported across the country and in much of the industrialized world, some scientists believe the increase is due to an expansion of diagnostic criteria and better identification of children with autism. However, a study commissioned by the California General Assembly concluded that the increase cannot be explained away by better data or past misclassification.

Some scientists, public health advocates and parents call it an epidemic. They are questioning whether some facet of modern society - toxic chemicals, vaccines, changes in lifestyle or diet - is stealing children's minds.

Relatively little is known about the cause of autism, first identified in 1943. Money for research was almost nonexistent until parents began lobbying Congress and raising funds themselves after autism rates began climbing in the 1990s.

"In 1993, there were probably 12 scientists in the whole country who were lonely and devoted and in a desert working on autism," said Shestack, who helped create the research foundation, Cure Autism Now, with his wife, Portia Iversen.

Autism has long been regarded as one of the most strongly inherited neurological disorders. Studies of identical twins show that if one twin has autism, the other twin will also have autism 60 percent to 80 percent of the time.

However, if genetics alone were the cause, the rate would be closer to 100 percent since identical twins have identical genes. Also, genetics alone cannot explain the apparent increases since, scientists say, there is "no such thing as a genetic epidemic."

"The only way you can explain the increase is if there are environmental factors that are strongly expressed and relatively widely distributed in the environment," said Dr. Mike Merzenich, a neuroscientist at the University of California-San Francisco.

Scientists already know that chemical exposure during pregnancy can cause autism. A third of the children of women who took thalidomide - a drug used in the 1960s to treat morning sickness that is infamous for causing deformed arms and legs - were also autistic if the exposure took place between the 19th and 24th day of pregnancy, which coincides with the beginning stages of brain development.

"I think it's a fair assumption that it's probably going to be genes plus some environmental factor," said David Amaral, research director of the MIND Institute in Sacramento, Calif. The mission of the institute, founded by four fathers of autistic children, is to find the causes of childhood neurological disorders generally and autism in particular.

"Environmental factors could play on the brain at any point in time," said Amaral, a professor of medical psychiatry at the University of California-Davis. "It could be maternal ingestion of mercury or postnatal lead exposure - we don't have consistent enough facts about autism to know ... ."

About 30 percent of autism cases are accompanied by seizures. Infections, immune system problems and food allergies also seem to be involved, along with gastrointestinal problems and sleep disturbances.

Children with other neurological conditions such as attention deficit-hyperactivity disorder, learning disabilities and anxiety disorders often have immune system problems as well, scientists said.

The immune system problems are "a very important clue," said Dr. David Carpenter, director of the Institute for Health and the Environment at State University of New York-Rensselaer. "The immune system has functions that regulate the brain function that we hadn't previously understood. For instance, the dementia that comes with age is basically an immune system disease."

Scientists also note that toxic chemical exposure often results in damage to more than one bodily system. The immune system and the nervous system share similarities in that they are both signaling systems.

Likewise, viruses usually affect more than one system and are also a focus of research. Scientists know, for example, that mothers who contract influenza during the first trimester of pregnancy are more likely to have children who develop schizophrenia.

"What frightens me is the number of environmental toxins and environmental influences that we don't know anything about," Amaral said.

More than 80,000 new chemicals have been introduced into the marketplace since the post-World War II rise of the petrochemical industry. In most cases, there is no publicly available test data on their potential neurodevelopmental effects on the fetus and young children through long-term, low-dose exposure or at critical windows in development.

In the largest study of its kind, researchers at the University of California-Davis are preparing to study 2,000 children - including 700 children with autism - to see if there are genetic patterns or patterns of chemical exposure in autistic children that are not found in the general population.

Among the chemicals that children will be tested for are PCBs - chemicals widely used to insulate electrical equipment but banned in the 1970s because of their toxic effects. Tests also will be done on their chemical cousins, PBDEs, as well as a variety of heavy metals such as mercury and lead, pesticides, medications, and compounds found in cleaning products, cosmetics and other consumer items.

"We're trying to understand if kids with autism have significantly different levels of chemicals of environmental concern and whether they are more sensitive than the typical child to the same exposure," said toxicology professor Isaac Pessah, who is overseeing the research.

PBDEs are flame retardants widely used in the foam cushions inside furniture and car seats; the hard plastic casings of computers and other office equipment; and hundreds of other products. Little attention had been paid to them until five years ago when Swedish researchers discovered them in the breast milk of nursing mothers. The highest levels recorded by far have been in American women.

PBDEs are of special interest, Pessah said, "because that is what kids are being exposed to in relatively high levels in their homes. These flame retardants aren't off somewhere in a Superfund toxic waste site - they are incorporated into computers and many other conveniences of modern life."

Autistic children often show no sign of the disorder at birth and appear to develop normally until about 15 months of age when they suddenly regress, losing the few words and skills they have learned.