A few decades ago, autism was routinely blamed on the “refrigerator mother”—a woman whose inability to bond stunted her child’s emotional growth. Now autism is seen as a complex condition that investigators are inching closer to deciphering.
In a major development, UCLA geneticist Rita Cantor recently pinpointed the location of an autism gene. Cantor and her colleagues analyzed the DNA of two large, unrelated groups of autism patients and their families. In both groups, the disorder was linked to a particular bit of genetic real estate on chromosome 17, called 17q21. The segment contains several genes, one of which raises the risk of autism. It was found only in boys with the disorder, which makes sense, Cantor says. Autism occurs much more frequently in males than in females. “It may be that this gene is expressed only in the brains of boys or that girls have protective factors,” Cantor says. Pinning down the actual gene could take another one to four years. Although other autism genes almost certainly exist, Cantor says, the discovery is a “crucial first step” toward figuring out the cause of autism and developing treatments.
Meanwhile, acting on a hunch that a faulty immune system may play a part in triggering autism, immunologist Judy Van de Water of the University of California at Davis investigated how the blood cells of autistic children react to foreign compounds like tetanus toxin and lipid molecules on the surface of Escherichia coli bacteria. She discovered that the protective cells of autistic youngsters mount a less vigorous defense against bacterial compounds than do those of normal children. The research adds fuel to the theory that environmental factors contribute to autism. “The immune system plays a huge role in neurodevelopment, so a defect there could affect the neurodevelopment of the child,” says Van de Water. Her work could lead to screening tests that identify—and perhaps protect—at-risk babies. “We may not catch everyone,” she says, “but if we could whittle down the number of affected kids, that would be great.”
