A severe NTD, craniorachischisis, is found in several mouse PCP-signaling mutants, including loop-tail (Lp) [Vangl2] mutants, crash [Celsr1] mutants, circletail [Scribble1], dishevelled 1 (Dvl1) and Dvl2 double mutants, and frizzled 3 (Fz3) and Fz6 double mutants [45–50]. This evidence concerns the gene DVL1 and craniorachischisis.