Understanding Autism

People can build lives around these talents. Thirty-one-year-old Eric Spencer of Flemington, N.J., started reading when he was 18 months old. His autism has always confined him to well-controlled environments; he lives near his parents, aided by a "life-skills coordinator." But his love of letters--individual letters--has been a lifeline. A local library has exhibited his calligraphy, and he sometimes visits nursery schools to carve children's names from poster board for them. To earn money, he sorts documents at Ortho-MacNeil Pharmaceuticals. "My job," he says, "is getting along perfectly."

How do people end up this way? Why do their minds exhibit these quirks? "We're at a very primitive stage of research," says David Amaral, a neuroscientist at the University of California, Davis, and research director at the MIND Institute, which just received $34 million in state funding to study autism and other neurological disorders. "We don't know what causes autism, or which areas of the brain are most affected." Autopsies of autistic people have found that cells in the "limbic" regions that mediate social behavior are often small and densely packed, suggesting their early development was interrupted. And neural-imaging studies are showing differences in how autistic and nonautistic brains respond to social cues, such as faces or eyes. Researchers at Stanford are now launchinga multicenter study to identify the most salient ones and assess their significance.

Other scientists are zeroing in on possible differences in brain chemistry. This spring, in a preliminary study, a team led by Dr. Karin Nelson of the National Institutes of Health discovered what may be a chemical marker for autism. The researchers identified 246 teenagers whose blood had been sampled at birth as part of the California Newborn Screening Program. Some of the teens were healthy, while others suffered from autism, cerebral palsy or mental retardation. And when the scientists examined their early blood samples, those from the autistic or retarded kids showed high levels of four proteins involved in brain development (VIP, CGRP, BDNF and NT4). The findings "suggest that some abnormal process is already underway at birth," says Dr. Judith Grether, a California epidemiologist who coauthored the study. If further research confirms the pattern, we may someday be able to test prenatally for autism.

Unfortunately, we still won't know what precipitates the condition. There is no question that heredity leaves some people susceptible. Roughly 5 percent of kids with autistic siblings have autistic disorders themselves (that's about 25 times the usual rate). And the risk of autism is 75 percent (375 times higher than usual) among people with affected identical twins. Researchers are studying "hot spots" on several chromosomes that could harbor culpable genes, but none of those regions has been linked consistently to the disorder. Experts assume the problem stems not from a single gene but from 10 or more that occur in various combinations. "Everyone agrees there is a genetic predisposition," says Bristol Power of the NICHD. "The question is: what triggers the condition in people who are predisposed?"

This is where things get murky. Some activists, including Rik and Janna Rollens, fear that childhood vaccines may trigger autistic disorders in susceptible kids. Others suspect that toxic substances are somehow to blame. Bobbie and Billy Gallagher started to wonder about environmental hazards several years ago, after two of their three kids were diagnosed as autistic. The Gallaghers live in Brick Township, N.J., a working-class town with a well-known toxic landfill. And when they sought out other afflicted kids, they were surprised to find 44 of them among Brick's 71,000 residents. Two years ago they demanded an inquiry, and they got one. In a report released this spring, federal investigators concluded that Brick's rate of autistic disorders was three times the 1 in 500 usually cited as the norm. They noted that small, intensive studies often find rates this high--an indication that the official estimates may be low--but they found nothing in the landfill, the water supply or the local river that looked like a plausible culprit.

That isn't to say toxic substances are off the hook. Many of the babies exposed prenatally to thalidomide during the late '50s suffered from autism as well as birth defects, and other substances could turn out to have similar effects. Dr. Eric Hollander of New York's Mount Sinai School of Medicine noticed several years ago that 60 percent of the autistic patients in his clinic had been exposed in the womb to pitocin, the synthetic version of a brain chemical (oxytocin) that helps induce labor. That could be significant, since only 20 percent of all births are assisted by pitocin. Or it could be a meaningless coincidence. In the hope of finding out, Hollander is now tracking 58,000 kids whose mothers' treatments were monitored during pregnancy.