The study zeros in on the genes that may lead to the marked extroverted behavior seen in children with Williams syndrome, demonstrating that "hyper-sociability" especially the drive to greet and interact with strangers -- follows a unique developmental path.
The path is not only different from typical children but also from children with other developmental disorders of the nervous system. The study appears in the online version of the American Journal of Medical Genetics.
Teresa Doyle and Ursula Bellugi of the Salk Institute, along with Julie Korenberg and John Graham of UCLA and Cedars-Sinai Medical Center, Los Angeles, found that children with Williams syndrome scored significantly higher on tests measuring behavior in social situations, including their ability to remember names and faces, eagerness to please others, empathy with others' emotions and tendency to approach strangers.
The authors also performed genetic screening on a young girl to look for genetic underpinnings of this pronounced social behavior.
"We've known for many years that children with Williams syndrome are markedly more social than other children, in spite of the moderate mental retardation and physical problems that also are associated with the disorder," said Doyle. "Here we not only have shown hyper-social behavior as a hallmark symptom that follows a characteristic developmental course in Williams syndrome, but we may be closer to identifying the genes involved in regulating that behavior."
Williams syndrome is rare, occurring in only one in every 20,000 people. It arises from the deletion of no more than 20 genes from one chromosome of the seventh chromosome pair.
Virtually everyone with Williams syndrome has exactly the same set of genes missing. People with the disorder have characteristic facial a
Contact: Andrew Porterfield