Epidemiological analysis of multi-site closure failure of neural tube in humans.

Van Allen et al. [Am J Med Genet 47:723-743, 1993] proposed that there is multi-site initiation of neural tube closure in humans, and that neural tube defects (NTD) represent the failure of one or more of 5 closure sites. We have studied from an epidemiologic perspective 774 liveborn infants with NTD by site of lesion following the multi-site classification proposed by Van Allen et al. [1993]. As predicted by these authors, we could classify all the cases with NTD by the multisite closure model. We have also estimated the prevalence of each failure closure site. This analysis indicates that not all the sites are affected with similar frequency.