(HealthDay News) – In patients with Williams Syndrome, which is characterized by a deletion of nearly 30 genes and altered social behaviors, levels of the neuropeptide oxytocin are associated with the altered behaviors, according to a study published online June 12 in PLoS One.

Noting that oxytocin and arginine vasopressin regulate reproductive and social behaviors in mammals, Li Dai, PhD, from the University of Utah in Salt Lake City, and colleagues examined oxytocin and arginine vasopressin levels at baseline and in response to a positive emotional intervention (music) and a negative physical stressor (cold) in 13 patients with Williams Syndrome and eight control subjects.

The researchers found that patients with Williams Syndrome had higher median levels of oxytocin at baseline and a less marked increase in arginine vasopressin. After exposure to music and cold, their levels of oxytocin and arginine vasopressin increased, with greater variability and greater peak release than the control subjects. In patients with Williams Syndrome, increased baseline levels of oxytocin but not arginine vasopressin were positively associated with a desire to approach strangers and negatively associated with adaptive social behaviors.

“These results indicate that Williams Syndrome deleted genes perturb hypothalamic-pituitary release not only of oxytocin but also of arginine vasopressin, implicating more complex neuropeptide circuitry for Williams Syndrome features and providing evidence for their roles in endogenous regulation of human social behavior,” Dai and colleagues conclude.

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