DVL2 and craniorachischisis: PCP-dependent CE is critical for neural tube closure, as loss of function alleles of Vangl2, Dvl and Dvl2, Celsr1, and Fzd3 and Fzd6 cause craniorachischisis (Greene et al., 1998; Curtin et al., 2003; Wang, Y. et al., 2006; Etheridge et al., 2008).