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• The immune system may play a critical role in the development of at least some types of autism. This suggests some new avenues of prevention and treatment.
• Many classic symptoms of autism spinning, head banging, endlessly repeating phrases appear to be coping mechanisms rather than hard-wired behaviors. Other classic symptoms a lack of emotion, an inability to love can now be largely dismissed as artifacts of impaired communication. The same may be true of the supposedly high incidence of mental retardation.
• The world of autism therapy continues to be bombarded by cure-of-the-day fads. But therapists are beginning to sort out the best ways to intervene. And while autism is generally a lifelong struggle, there are some reported cases in which kids who were identified as autistic and treated at an early age no longer exhibit symptoms.
THE CURIOUS INCIDENCE
Dr. Thomas Insel, Director of the National Institute of Mental Health (NIMH), which funds much of the nation's autism research, remembers a time when the disorder was rarely diagnosed. "When my brother trained at Children's Hospital at Harvard in the 1970s, they admitted a child with autism, and the head of the hospital brought all of the residents through to see," says Insel. "He said, 'You've got to see this case; you'll never see it again.'"
Alas, he was mistaken. According to the Centers for Disease Control and Prevention (CDC), about 1 in 166 American children born today will fall somewhere on the autistic spectrum. That's double the rate of 10 years ago and 10 times the estimated incidence a generation ago. While some have doubted the new figures, two surveys released last week by the CDC were in keeping with this shocking incidence.
No one can say why the numbers have soared. Greater awareness and public health campaigns to encourage earlier diagnosis have surely played a part, since in the past, many such children were probably labeled retarded or insane and hidden in institutions. But environmental factors may also be contributing to the spike. To get to the bottom of that mystery and others, federal funding for autism research has more than tripled in the past decade, to $100 million, although it pales in comparison with the estimated $500 million spent on childhood cancers, which affect fewer youngsters.
At the Center for Children's Environmental Health and Disease Prevention at the University of California at Davis, toxicologist Isaac Pessah is studying hair, blood, urine and tissue samples from 700 families with autism. He's testing for 17 metals, traces of pesticides, opioids and other toxicants. In March Pessah caused a stir by releasing a study that showed that even the low level of mercury used in vaccines preserved with thimerosal, long a suspect in autism, can trigger irregularities in the immune-system cells at least in the test tube. But he does not regard thimerosal (which has been removed from routine childhood vaccines) as anything like a smoking gun. "There's probably no one trigger that's causing autism from the environmental side," says Pessah, "and there's no one gene that's causing it."
Indeed, most researchers believe autism arises from a combination of genetic vulnerabilities and environmental triggers. An identical twin of a child with autism has a 60% to 90% chance of also being affected. And there's little doubt that a vulnerability to ASD runs in some families: the sibling of a child with autism has about a 10% chance of having ASD. Gene scientists working on autism have found suspicious spots on chromosomes 2, 5, 7, 11 and 17, but there are probably dozens of genes at work. "We think there are a number of different autisms, each of which could have a different cause and different genes involved," says David Amaral, research director of the MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, also at U.C. Davis.