Williams (Beuren) syndrome (WS or WBS)

The syndrome was first described by the cardiologists Williams and Beuren. It is present in one out of 10,000 births.The disorder is caused by the deletion of genetic material from the long arm of chromosome 7. This means, among other things, that the gene that codes for the protein elastin is missing.As elastin contributes to the creation of connective tissue, this syndrome’s most common mutations affecting the heart and the large blood vessels that begin or end there concern the reduced pliability of the connective tissue. More than 80 per cent of the affected children have disorders related to the structure of the heart muscle and the large blood vessels.These typically include constriction of the main artery above the aortic valve (known as the supravalvular aortic stenosis), as well as of the pulmonary artery; the syndrome also often encompasses ventricular septal defects. The affected children have a typical appearance, a deep hoarse voice, are underdeveloped, noise sensitive and have defective vision. They are often mildly to moderately intellectually challenged and have delayed development. The life expectancy of those affected is normal.