abnormal neural tube morphology/development abnormal neural crest morphology MP:0009846 MPheno.ontology any structural anomaly of the specialized region of ectoderm found between the neural ectoderm (neural plate) and non-neural ectoderm and composed of highly migratory pluripotent cells that delaminate in early embryonic development from the dorsal neural tube and give rise to an astounding variety of differentiated cell types