WNT1 and Brachycephaly: At postnatal day (P) 1, all (16 of 16) Hand2CAT/+; Wnt1-Cre (hereafter Hand2NC) mice died neonatally with craniofacial deformities, including brachycephaly, eyelid colobomas, tongue protrusion, and small pinna in the anterior position, compared to control littermates (Fig. 2Ab; Supplementary Table S1).