WNT9B and cleft palate: Among them, WNT3 and WNT9B/Wnt9b mutations are associated with cleft palate/lip phenotype in humans and mice, respectively (Niemann et al., 2004; Menezes et al., 2010; Jin et al., 2012; Fontoura et al., 2015), suggesting that they are specific WNT ligands critical for facial development.