Heterozygous loss-of-function mutations in PRDM16 have been shown to be sufficient to cause left ventricular noncompaction and a loss-of-function mutation in ECE1 was identified in an individual with patent ductus arteriosus, a small subaortic ventricular septal defect and a small atrial septal defect, Hirschsprung disease, and autonomic dysfunction [9], [10]. The gene discussed is ECE1; the disease is atrial septal defect.