Vascular basis for neural tube defects: a hypothesis.

A hypothesis is set forth that neural tube defects are produced by inadequate nutrient supply to the rapidly growing neural folds. According to this hypothesis, a delay in establishing blood flow or an aberration of blood supply to neural tissue may interfere with nutrition and prevent neural tube closure. The hypothesis was tested by examining the vasculature of fetuses with spinal neural tube defects. In each case, the arterial supply to the region of the neural tube defect was disturbed. Because development of arterial supply to the neural folds predates neural tube closure, these vascular abnormalities are considered to be primary malformations that lead to neural tube defects rather than secondary morphologic disturbances resulting from neural tube defects.