Wnt1-Ate1 mice have perinatal lethality.

(A) A Wnt1-Ate1 pup that died at birth from breathing defects as shown in the Video S1. In such pups labored breathing leads to bloating (left) and prominent air accumulation in the stomach (right). (B) Wnt1-Ate1 pups that survive after birth (indicated by arrows) shown at postnatal day 5 (P5) are smaller than their wild-type littermates and are significantly less active at day 9 (Video S2), suggesting growth and behavioral retardation. (C) Wnt1-Ate1 (KO) mice that survive to adulthood are smaller than control (WT, top) and have short snouts and abnormally shaped skulls (bottom).