GTF2IRD2B and glycogen storage disease VI: The Deletion of GTF2IRD2B leads to a rare congenital disease called Williams-Beuren syndrome, which frequently presents with supravalvular aortic stenosis (SVAS; OMIM 185500), a congenital heart defect characterised by the narrowing of the aorta, pulmonary and coronary arteries and other blood vessels [35].