A considerable percentage of cardiac birth defects is caused by a failure in normal migration, differentiation or patterning of the cardiac neural crest (CNC). This subset of pluripotent neural crest stem cells forms in the dorsal aspect of the neural tube at the level of the mid-otic placode to the third somite [1]. Subsequently cardiac neural crest cells (CNCCs) delaminate, undergo a phenotypic transformation from an epithelial to mesenchymal cell type, and migrate latero-ventrally into the 3rd, 4th and 6th pharyngeal arch arteries (PAAs), where they contribute to the formation of the smooth muscle cell layer of endothelial structures derived from the aortic arch arteries [1-3]. A subset of CNCCs continues to migrate deeper into the aortic sac to form the aortico-pulmonary septum; a vital structure, which separates the pulmonary trunk from the aorta [4].