abnormal embryonic/fetal subventricular zone morphology +
abnormal neural plate morphology +
abnormal neural tube morphology +
abnormal neuron differentiation +
abnormal neuronal stem cell morphology
any structural anomaly of an undifferentiated cell that originates from the neuroectoderm and has the capacity both to perpetually self-renew without differentiating and to generate multiple types of lineage-restricted progenitors