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Drugs taken by some pregnant women are also coming under scrutiny. At the University of Rochester, embryologist Patricia Rodier and her colleagues are exploring how certain teratogens (substances that cause birth defects) could lead to autism. They are focusing on the teratogens' impact on a gene called hoxa1, which is supposed to flick on very briefly in the first trimester of pregnancy and remain silent ever after. Embryonic mice in which the rodent equivalent of this gene has been knocked out go on to develop brainstems that are missing an entire layer of cells.
In the end, it is not merely possible but likely that scientists will discover multiple routes--some rare, some common; some purely genetic, some not--that lead to similar end points. And when they do, new ideas for how to prevent or correct autism may quickly materialize. A decade from now, there will almost certainly be more effective forms of therapeutic intervention, perhaps even antiautism drugs. "Genes," as the University of Chicago's Cook observes, "give you targets, and we're pretty good at designing drugs if we know the targets."
Paradoxically, the very thing that is so terrible about autistic disorders--that they affect the very young--also suggests reason for hope. Since the neural connections of a child's brain are established through experience, well-targeted mental exercises have the potential to make a difference. One of the big unanswered questions, in fact, is why 25% of children with seemingly full-blown autism benefit enormously from intensive speech- and social-skills therapy--and why the other 75% do not. Is it because the brains of the latter are irreversibly damaged, wonders Geraldine Dawson, director of the University of Washington's autism center, or is it because the fundamental problem is not being adequately addressed?
The more scientists ponder such questions, the more it seems they are holding pieces of a puzzle that resemble the interlocking segments of Tommy Barrett's Transformer toys. Put the pieces together one way, and you end up with a normal child. Put them together another way, and you end up with a child with autism. And as one watches Tommy's fingers rhythmically turning a train into a robot, a robot into a train, an unbidden thought occurs. Could it be that some dexterous sleight of hand could coax even profoundly autistic brains back on track? Could it be that some kid who's mesmerized by the process of transformation will mature into a scientist who figures out the trick? --With reporting by Amy Bonesteel/Atlanta