Malformations of the cranium, vertebral column, and related central nervous system: morphologic heterogeneity may indicate biological diversity.

BACKGROUND: We conducted an autopsy study of neural tube defects (NTDs) to determine whether there is a relation between the localization of the lesion and the sex of the fetus or infant, and the presence of other malformations.
METHODS: Included were 97 autopsies of infants/fetuses with anencephaly or spina bifida at any level and weighing more than 500 gm. The topographical divisions studied were: 1) isolated cranial lesions, 2) superior spina bifida with or without occipital lesion, and 3) isolated lower spina bifida.
RESULTS: In group 1 (46 cases) there were lesions of the vertebral column, mainly cervical, and other anomalies of the "schisis" type. Group 2 (24 cases) showed more extensive involvement of the vertebral column and more cases with multiple anomalies (p = 0.001) of a varied spectrum, not only the schisis type; in group 3 (27 cases) the cases involved a few other malformations. In group 2 there was no sex preference (females 46%), but the other, more localized lesions (groups 1 and 3) were found predominantly in females (71%).
CONCLUSIONS: Localized lesions, whether involving the cranium or lumbar spine, are formed by a mechanism that favors the female gender, whereas upper spina bifida, which is usually accompanied by cranial involvement, results from another mechanism (possibly vascular disruption) and is frequently accompanied by other malformations.