People with Williams syndrome are known for their friendliness, although this tends to be coupled with heightened anxieties.
Mbemba Jabbi at the National Institutes of Health in Bethesda, Maryland, and colleagues studied MRI scans of 14 people with the syndrome. They found that the insula – a brain region involved in emotion – was smaller than in 23 people without the syndrome.
When Jabbi's team used PET scans to examine the insula in more detail, though, they found that one area of the right insula was larger in people with Williams syndrome. Those with more extreme personality differences had more grey matter here.
The findings could help predict how social symptoms of the syndrome might develop, says Debbie Riby at Newcastle University, UK. However, the people who participated in the study have a normal IQ, which is typical of only a small percentage of those with Williams syndrome, she says.
