Observations on patients with neural-tube defects in a metropolitan hospital clinic: an epidemiological history.

A survey of the population of the Spina Bifida Service (107 patients) of Georgetown University Hospital, Washington, D.C., and of a control population in the same hospital revealed that, although situated in an ethnically heterogeneous area, Service patients with a history of neural-tube defects in siblings or family significantly more often had ancestors on both sides from the British Isles than did either isolated cases or the controls. In addition, of 107 families reviewed, nine had more than one affected child, nine had a positive family history for neural-tube defects, and nine of the patients and seven of an estimated total of 220 siblings had an unrelated major birth-defect. These incidences are among the highest published so far. Contrary to other surveys, there was no deficiency of twinning among the sibships, nor of males among the Spina Bifida Service patients. These observations indicate the desirability of studying each population of patients with neural-tube defects in order to provide more realistic counseling and so that clues may be gathered as to the genetic mechanisms and environmental factors which led to the production of such defects.