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Autism can suddenly devastate a child’s ability to talk and interact with others. What causes it and how can it be stopped?

By Melissa Hendricks
Photos by David Colwell

Alex Bush wants a second bowl of Goldfish snacks. He stands in front of his mother in the living room of his family’s suburban Baltimore home, bouncing on the balls of his feet and pressing together the fingertips of his left and right hand to form the sign language gesture for “more.”

“No, Alex, you’ve already had some,” says Sandy Bush. Alex repeats the gesture and looks at his mom with intense, dark brown eyes. He is a handsome 11-year-old, with dark hair shaved close to his head and a tanned, muscular body.

“Okay,” says Sandy Bush, relenting. “But first give me a kiss. A kiss, Alex. Give me a kiss.” Alex slowly leans forward and lightly kisses his mother who then goes to the kitchen. When she returns with a bowlful of crackers, Alex places his hand on his chest—the gesture for “thank you.”

Alex likes a lot of the stuff that other kids his age do. He loves holding a ball, bouncing on his backyard trampoline, watching videos, and eating cookies and junk food. But Alex cannot tell you any of these things. He is autistic, and for the past six and a half years, he has not spoken. He communicates with the three sign language gestures he knows, or by taking his mother’s hand and placing it on the thing he wants. 

Diagnoses have soared in the past decade—some states report autism increasing by 25 percent per year.

A few miles away from Alex’s home lives another boy just a year older than Alex who also has autism. John Gillin can speak and loves to read, especially books about colonial America, novels by Roald Dahl and anything about geography. For relaxation, he’ll read the atlas and almanac. When a visitor comes to his home, he knows to say, “Hey, how’s it going? I’m John. Who are you?” But beyond such scripted lines, John has trouble making casual conversation. He responds slowly to people’s questions and misses the non-verbal aspects of social interaction.

The big differences between Alex and John illustrate one of the many challenges confronting researchers who are trying to figure out what causes autism. What sort of model could explain a disorder that deprives one child of language but affects another in ways that might be apparent only to a trained professional?

Scientists know that autism is a brain disorder that impairs the ability to communicate and socialize, and can cause a person to engage in repetitive or ritualized behaviors or to be unusually sensitive to light, sound or touch. Beyond that, much about autism remains a mystery.

“We know very little about the causal risk factors of autism,” says Craig Newschaffer, an associate professor of Epidemiology and Mental Health. “It’s critical we find some answers.”  

Hopkins’ Leo Kanner first diagnosed autism in 1943.

Newschaffer directs the Bloomberg School’s Center for Autism and Developmental Disabilities Epidemiology (CADDE). It is one of six regional centers for autism research established by the Centers for Disease Control and Prevention (CDC) in response to a dramatic rise in autism over the past decade. Some states have reported autism climbing 25 percent per year. Those rising rates have generated a lot of publicity, most of it focused on a debate over whether the measles-mumps-and-rubella vaccine routinely given to American toddlers has fueled an “autism epidemic.” In May, a report by the National Academy of Sciences’ Institute of Medicine concluded that the evidence did not support the vaccine-autism hypothesis. Still, some parent groups see the vaccine as the culprit.

Newschaffer and  colleagues at CADDE and the other CDC-funded autism research centers are conducting a broader investigation into autism’s causes and risks. They are about to launch one of the largest autism epidemiology studies ever conducted. It will involve almost 2,000 children, ages 3 to 5, and their parents, and include children with autism, those without it, and a group with other neurodevelopmental disabilities whom researchers will study to identify differences that could increase autism’s risk. Investigators will also give the mothers detailed questionnaires about their medical histories and pregnancies in hopes of uncovering events that might have increased their risk of having an autistic child. Results of the far-reaching study are not expected until the end of the decade.

Meanwhile, researchers have no shortage of leads in the search for autism’s cause. Gene-hunting studies suggest dozens of different genes with possible ties to autism; according to one model, 10 to 20 genes play a role in any one case of autism. But so far, no one has clearly demonstrated an “autism gene.” Researchers also suspect a number of different environmental factors. “Nothing has been definitively linked,” says Newschaffer. “Zero.” Scientists also know that autism strikes four times as many boys as girls, but that fact hardly narrows the search for a cause. (more)