A visceral heterotaxy characterized by complete atrioventricular septal defect with a common atrium and univentricular AV connection, total anomalous pulmonary drainage, and transposition or malposition of the great arteries and may be associated with bilateral trilobed lungs, midline liver, asplenia and situs inversus affecting other organs that has material basis in homozygous mutation in the GDF1 gene on chromosome 19p12. The disease is MONDO_0008832 (right atrial isomerism). Also known as: Ivemark Syndrome, Ivemark syndrome, asplenia with cardiovascular anomalies, right atrial isomerism (disease), right atrial isomerism (ivemark).