Tricuspid atresia is (TA) a rare congenital heart malformation characterized by the congenital agenesis of tricuspid valve leading to severe hypoplasia of right ventricle (functionally univentricular). TA is associated with normally related or transposed great vessels (TGV), an obligatory interatrial connection that is crucial for survival (patent foramen ovale or atrial septal defect, osteum secondum type), ventricular septal defect (in 90% cases), pulmonary outflow obstruction - pulmonary atresia, stenosis or hypoplasia (usually in TA with normally related vessels but also in TGV), aortic coarctation and/or aortic arch interruption (usually in TA with TGV). The disease is Monarch Disease Ontology id MONDO_0011514 (tricuspid atresia). Also known as: congenital atresia of tricuspid valve, tricuspid atresia (disease), tricuspid valve atresia.