(A) Representative photograph of t2 KO pups and cyanotic DKO littermates at E18.5. Scale bar: 1 cm. (B) Body weight of t2 KO (n = 68) and DKO (n = 51) embryos at E18.5. *P < 0.05. (C) Lung sections from t2 KO embryos and DKO littermates were stained with HE. Scale bar: 100 μm. (D-H) Skeletal whole body (D), upper limb (E), lower limb (F), lumber spine (G), and cranial bone (H) preparation. (I) Humeral and tibial bone length at E18.5 of t2 KO (n = 5) and DKO (n = 10) mice. **P < 0.01.