Genetic and embryological approaches to studies of neural tube defects: A critical review

Experimental embryological models have suggested that the morphology and qu antity of neural tube defects may be governed by their position along the a nteroposterior axis of the embryo. Inductive interactions and genetic regul ation during axis development may play a role in the patterning of neural t ube defects. A major challenge in the study of human neural tube defects is determining whether the spectrum of developmental neural tube anomalies fo und in individuals and their families mirror experimental models and are re gulated by similar processes. We have found that the various neural tube de fect phenotypes can be clustered according to their position along the ante roposterior axis. The findings correlate well to the pattern of early genes expression, inductive models of the embryonic axis, and mutant NTD animal models. We suggest that NTD should be studied by their location along the a nteroposterior axis and that specific mutant genes may be identified by the observed pattern of NTD in an individual or a family.