Anomalies of heart, spleen, kidneys, gut, and limbs may result from an overdistended neural tube: a hypothesis.

A hypothesis is advanced that many congenital anomalies of non-neural organs may be produced by damage to their mesodermal or entodermal anlagen caused by overdistention of the embryonic neural tube. Evidence to support the hypothesis derives from: (1) seldom appreciated but unequivocal embryologic facts about prechoroid plexus neural tube morphogenesis; (2) an understanding of the role of neural tube overdistention in the production of various dysraphic conditions; (3) the frequency of association of non-neural anomalies with dysraphic conditions; and 4) an analysis of the anatomic features of the organ anomalies associated with dysraphism. The practical utility of the hypothesis is that (1) it helps explain a seemingly widely divergent subset of phenomenology and (2) it is testable. At present, treatment of children with congenital anomalies is largely palliative. Prevention of these distressing defects in the future will only be realizable if the mechanisms of their genesis are more clearly understood.