WNT5A and Robinow syndrome: Severe skeletal defects including an extreme craniofacial phenotype can be observed in E18.5 Wnt5a−/− embryos, but Wnt5a global knockout is perinatal lethal in mice and is consequently neither usable for assessing postnatal craniofacial morphology nor likely representative of the Robinow syndrome patient population (Yamaguchi et al. 1999).