Why do only some institutionalized children become indiscriminately friendly? Insights from the study of Williams syndrome

Uncorrected proofWhy do some institutionalized children develop indiscriminate behavior (IB) while others do not? Consid- ering children with Williams syndrome (WS) may provide an answer because IB has been observed routinely among individuals with this rare genetic neurodevelopmental dis- order. By conceiving WS as a natural genetic model that mimics the indiscriminate phenotype and, more impor- tantly, is associated with the deletion of genes in a specific region, we propose an integrative conceptual framework that underscores the dynamic developmental interplay between genes, endophenotypes, and environment. In this article, we consider the etiology of IB among institutional- ized children, which emphasizes environmental factors, followed by the effect of such behavior on WS children’s hypersociability, which highlights the crosstalk between genes and neuropsychological features in programming their distinctive social-emotional/behavioral phenotype. We propose new hypotheses regarding the etiopathogenyof IBs in institutionalized children, particularly the pre- diction of specific gene-X-environment interactions.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/PSI-PCL/116897/2010; PTDC/PSI PCL/115316/2009; PTDC/PSI-PCL/101506/200