A 7 year old child with a genetic diagnosis of Williams-Beuren syndrome (microdeletion 7q11.23) had a ventricular septal defect, supravalvar and peripheral pulmonary artery stenosis, supravalvar aortic stenosis, and isolation of the left subclavian artery from the right aortic arch, originating from a patent ductus arteriosus. Cardiac catheterisation in infancy revealed systemic pressure …