The traditional description of cardiac development involves progression from a cardiac crescent to a linear heart tube, which in the phase of transformation into a mature heart forms a cardiac loop and is divided with the septa into individual cavities. Cardiac morphogenesis involves numerous types of cells originating outside the initial cardiac crescent, including neural crest cells, cells of the second heart field origin, and epicardial progenitor cells. The development of the fetal heart and circulatory system is subject to regulatation by both genetic and environmental processes. The etiology for cases with congenital heart defects (CHDs) is largely unknown, but several genetic anomalies, some maternal illnesses, and prenatal exposures to specific therapeutic and non-therapeutic drugs are generally accepted as risk factors. New techniques for studying heart development have revealed many aspects of cardiac morphogenesis that are important in the development of CHDs, in particular transposition of the great arteries.

Supravalvular aortic stenosis is associated with the Williams–Beuren syndrome, but it also occurs in a non-syndromatic congenital form. Anelastingene mutation of chromosome 7q11.23 is responsible in both cases. The vascular features are identical. These patients have a higher risk of sudden death, particularly when undergoing diagnostic or surgical procedures. We report the account of a family with a new mutation in theelastingene. Screening over three generations revealed eight affected individuals. The cardiac and vascular malformations ranged from mild asymptomatic supravalvular aortic stenosis and isolated dysplastic atrioventricular valves to diffuse arterial hypoplasia. Two infants presented arteries affected at multiple locations, including the left coronary artery. Both died of sudden cardiac death and myocardial ischaemia, one while under general anaesthesia for cardiac catheterisation, and the other perioperatively. We discuss the pathophysiological aspects in these patients that deserve consideration before any general anaesthesia is administered.