Fig. 3. Pitx2^+/-; Tbx1^+/- newborns and embryos exhibit cardiac defects. (A,D,E,F) Histological analysis of Pitx2^+/-; Tbx1^+/- newborns revealed severe heart defects such as double outlet right ventricle (dorv; arrow), stenosis of the infundibulum (arrowhead) (A), atrial septal defect (asd), ventricular septal defect (vsd) (D), atrio-ventricular valve defects (vad), a common atrio-ventricular junction (cav) (E) and abnormal drainage of pulmonary vein (pv) (F). Pitx2^+/- (B,G) and Tbx1^+/- (C,H) were normal. Histological analysis of Pitx2^+/-; Tbx1^+/- E10.5 embryos (J,L) shows grossly malformed hearts compared with wild-type embryos (I,K). ao, aorta; avc, atrio-ventricular canal; la, left atrium; lv, left ventricle; pt, pulmonary trunk; ra, right atrium; rv, right ventricle. Scale bars: 1 mm in A-H; 250 µm in I-L.