Chang and colleagues described a patient with atrioventricular septal defect and hypoplastic left ventricle who had a deletion of FOXP1; subsequently in 82 patients with atrioventricular septal defect or hypoplastic left heart syndrome, two patients with FOXP1 mutations were identified (one had hypoplastic left ventricle with mitral valve and aortic valve atresia, and another patient had atrioventricular septal defect, pulmonary atresia and single ventricle in the setting of heterotaxy syndrome) [12]. This evidence concerns the gene FOXP1 and familial atrioventricular septal defect.