Etiology I: Early Questions

And as a matter of fact, getting down to basics, one may ask, what is the reason for NTD. Fingers were early pointed at the nongenetic: “Dietary or other differences between communities seem more likely to be important nongenetic causes of anencephaly than a general effect of the external environment acting equally on all communities in a particular region….” Searle (1959). In the end it was a matter of understanding the genetic nature of discontinuous characters (malformed vs not malformed), as distinguished from continuous ones (hypertension, etc.), an intellectual challenge that was incompletely met (e.g. Edwards 1969).