In a familial form of isolated ostium secundum ASD that affects four individuals in a family of five with autosomal dominant inheritance, whole genome sequencing identified a new mutation (c.1784T > C) in the 3′-untranslated region (3′UTR) of ACTC1, which encodes the predominant actin in the embryonic heart [109]. This evidence concerns the gene ACTC1 and atrial septal defect.