Autism is a mysterious condition that many people first glimpsed in the movie Rain Man . With her children facing an uncertain future, Regina Rizzo wonders whether genetic research will eventually help - perhaps by leading to new drugs. In fact, autism has attracted many researchers because it seems more clearly genetic than, say, cancer or heart disease. It ravages families, often striking two or three siblings. The Rizzo family in Yardley is part of the investigation, having given blood to a database of more than 300 families known as the Autism Genetic Resources Exchange.
Researchers use the database to try to determine which genes are linked to autism.
What the genome projects did was to spell out most of the three billion characters of chemical code in the DNA of a small sample of humans. Monumental as those efforts were, they did not figure out what each gene does. And because they analyzed the DNA of healthy people, the results by themselves say nothing specific about disease. Autism runs in families, but not in the way it would if it were caused by a single-gene defect such as cystic fibrosis. In identical twins, about 60 percent share their autism, which scientists take as evidence of a genetic influence.