Mouse models of congenital heart defects: what's missing?

One of the puzzling things about genetic disruptions in mice that affect heart development is the overwhelming number of conotruncal anomalies and the infrequency with which certain other malformations are reported. For instance, venous malformations such as total anomalous pulmonary venous return (TAPVR) or partial anomalous pulmonary venous return (PAPVR) have not been reported in a mutant mouse. Coronary artery anomalies are reported infrequently, and when they are reported it is because they are obvious. Conotruncal anomalies such as common trunk, double-outlet right ventricle, and pulmonary stenosis with overriding aorta are frequently associated with mouse germ line and conditional gene deletions. Although conotruncal malformations represent the highest percentage of congenital heart defects in the human population, TAPVR and PAPVR occur in a significant number of babies. Further, coronary anomalies affecting the stems of the coronary arteries frequently are seen in conotruncal malformations in babies but are rarely reported in mouse models.