The Loss of Foxc2 Expression in the Outflow Tract Links the Interrupted Arch in the Conditional Foxc2 Knockout Mouse

Congenital heart disease is the most common birth defects, affecting 1 % live births [1]. The cardiovascular system undergoes a series of morphogenetic events to form a heart and an aorta in fetuses. Formation of the heart and aorta requires migration, differentiation, and precise interactions among multiple cells from several embryonic origins [2]. Forkhead box2 (Foxc2) encodes a transcription factor and is expressed in mesodermal tissues, such as the pharyngeal artery, outflow tract endothelial/surrounding mesenchyme, bone, and kidney [3]. Simple knockout of Foxc2 in mouse causes an interrupted aortic arch, ventricular septal defect, cleft palate, and skeletal malformation [4]. The heart is made from primary and secondary heart field progenitors. The primary heart field gives rise to the left ventricle and atria, while the secondary heart field contributes mainly to the right ventricle and outflow tract [5] (Fig. 27.1).