(A) Gross morphology of P1 Nkx2–5∆enh/∆enh and wildtype (Nkx2–5+/+) littermates. (B) Neonatal mouse survival curves in Nkx2–5+/+, Nkx2–5∆enh/+, and Nkx2–5∆enh/∆enh mice. P<0.0001 by logrank test for all three genotypes. (C, G) Representative wholemount and histological assessment of Nkx2–5+/+ hearts with normal anatomy. (D−F and H−J) Representative wholemount and histological assessment of Nkx2–5∆enh/∆enh hearts showing double-outlet right ventricle (DORV) (D, H), dextro-transposition of great arteries (d-TGA) with ventricular septal defect (VSD) (E, I), and persistent truncus-arteriosus (PTA) with VSD (F, J). PA, pulmonary artery; Ao, aorta; T, truncus arteriosus; LV, left ventricle; RV, right ventricle. Scale bars for C−F: 2 mm. Scale bars for G−J: 500 µm.