HAND2 and tricuspid atresia: HAND2 mutations/absence associated with early embryonic lethality; valve defects, such as tricuspid atresia; double inlet left ventricle; hypoplastic myocardial tissue; rightward shift of the interventricular septum with larger left and smaller right ventricle; hypotrabeculated myocardial tissue with multiple interventricular septa; hypervascularization with multiple coronary arteries [219] (mouse)