Null and heterozygous Zic3 mice display a variety of cardiac defects such as TGA, interrupted aortic arch (IAA), atrial septum defect (ASD) and ventricular septal defect (VSD) in combination with various other developmental anomalies, thus resulting in a phenocopy of the clinical spectrum of malfunctions found in humans with heterotaxy [25]. Here, ZIC3 is linked to ventricular septal defect.