Human genetics of atrial septal defect

Atrial septal defects and other interatrial communications share the physiologic phenotype of shunting blood from the left to the right atrium, but their genetics and development have important differences. Secundum ASDs are the most common and usually the type implied by clinicians when not otherwise specified. The distinction is important because the development and genetics of ostium primum ASDs, the second most common type, are related to atrioventricular septal defects. Sinus venosus and coronary sinus defects are rare. Their anatomy and development are more properly considered as an interatrial communication rather than a true septal defect. Little is known about their genetics. This chapter focuses on the human genetics of secundum ASD and sinus venosus and coronary sinus defects.