Contributing gene finally found.

• Position: Autism

Scientific research has discovered that a specific gene contributes to autism and that autistic people have fewer receptors for the brain messenger acetylcholine, as well as more tightly packed columns of neurons in the cerebral cortex. Another study found that autistic children were less able to discriminate similar sounds than were other youngsters. The research is providing new clues to the genetic, neurological, and molecular basis of this still mysterious disease.

Autism is a disorder that affects two to six of every 1,000 children--mostly boys. It actually encompasses a wide array of symptoms--called autism spectrum disorder (ASD)--including various degrees of behavioral, developmental, and sensory deficits. Many first became aware of autism with the 1988 movie "Rain Man," starring Dustin Hoffman as a middle-aged autistic savant with tremendous mental capabilities. In reality, only about 10% of autistic people display signs of genius--typically in mathematics, music, or art.

Although autism long has been identified as a genetic disease, the genes that contribute to it have been difficult to track down. Unlike Huntington's disease or Down syndrome, in which a single gene or an entire chromosome is inherited, many gene mutations probably are involved in autism. Now the laboratories of James Millonig and Linda Brzustowicz at the University of Medicine and Dentistry, New Brunswick, N.J., have isolated a specific gene that contributes to ASD.

In searching for the gene, the pair focused on previous research showing that autistic people often have a...