© 2014 Elsevier Inc. All rights reserved.Congenital heart defects have always had special place among birth defects for clinical geneticists. They are both common and serious with an estimated prevalence of approximately 8 in 1000 births and are the most common cause of birth defect-related death (Hoffman and Kaplan, 2002). They are often the first anomaly to present in a child and, as many are life threatening, they also typically command the greatest attention. For these reasons, they are the defining birth defect for many genetic syndromes. For example, supravalvular aortic stenosis is linked with Williams syndrome, pulmonary stenosis with Noonan syndrome, and coarctation of the aorta with Turner syndrome. However, only one-third of heart defects present as one component of a genetic syndrome, with the remainder occurring as an isolated finding (Ferencz et al., 1989).