Eur J Anat, 10 (3): 115-120 (2006)

Neural tube closure defects: A discussion of current models and clinical presentation of a skull from the Museum of Anatomy of a Brazilian University

Machado Fonseca D.J., Marques S.R., Prates J.C., Cotecchia Ribeiro E., Smith R.L., Garcia Alonso L.

Division of Descriptive and Topographical Anatomy, Department of Morphology and Genetics, Federal University of Sao Paulo - Paulist School of Medicine, Sao Paulo, Brazil; Disciplina de Anatomia Descritiva e Topográfica, Departamento de Morfologia e Genética, Edifício Leitão da Cunha, Rua Botucatu, 740, São Paulo - SP - 04023-900, Brazil

ABSTRACT Currently, neural tube defects (NTD) have an incidence rate of 1/1000 of those born alive. Their occurrence relates to the primary neurulation period. In this context, there are two main embryogenesis models that attempt to explain neural tube closure: the continuous closure model and the multisite closure model. In this work, we studied a skull with NTD from the collection of the Federal University of São Paulo, Paulist School of Medicine, where the cephalic perimeter and index were measured and the dental arcade was used to estimate chronological age. From this analysis we conclude that this was a microbrachycephalic skull, with anterior fontanelle disjunction and a neural tube closure defect at site 2, according to the multisite classification model. In general, NTDs present a high degree of clinical and etiologic heterogeneity. The causes for this broad diversity of defects are the intrauterine involvement of teratogenic factors, among them maternal alcoholism, use of carbamazepine during pregnancy, and folic acid deficiency, among others. There are many genes potentially involved in this class of defects configuring as multifactorial. Thus, the multisite closure model allows one to explain many of these defects by suggesting the possibility of a different genetic control for each closure site, together with different sensitivities to environmental factors, both interacting with each other as a probable NTD etiology.

Keywords: carbamazepine, age determination, alcoholism, article, Brazil, cell heterogeneity, clinical feature, disease model, embryo development, folic acid deficiency, genetic variability, human, incidence, medical school, microcephaly, neural tube defect, pathogenesis, skull defect, teratogenesis