1. Williams syndrome phenotype
Williams syndrome (WS) is a rare neurodevelopmental condition that has been identified as having unique medical, cognitive and behavioural features associated with deletion of multiple adjacent genes at chromosome 7. As discussed in thesubsequent sections deletions of the elastin gene (ELN) plays a major role in the development of the cardiovascular and dysmorphic features. Other genes in the microdeletion region may contribute to other characteristics or traits, especially development of the central nervous system (CNS) and peripheral nerves.