May spina bifida result from an X-linked defect in a selective abortion mechanism?

The Nature and Causes of Spontaneous Abortions with Normal Karyotypes

“…Since, as has been emphasized, few such studies concern themselves with the morphology of the conceptus, it is not impossible that many of the clinically important etiological factors act independently of the nature of the conceptus. Theoretically they might act as cofactors; thus it has been suggested that spina bifida might result from an X-linked defect in an unproven selective abortion mechanism (Burns and Gibbons, 1978). Similarly it was proposed that, since thalidomide had a mild immunosuppressive function, the high incidence of limb malformations was due to failure of rejection of these abnormal fetuses (Hellmann, 1966).…”

Neural tube defects as an X‐linked condition

“…The possibility of X-linked genes being involved in the predisposition to neural tube defects was explored by Burn and Gibbens (1979), but these authors suggested an X-linked dominant mechanism to account for the striking female excess among infants with neural tube defects in areas of high incidence. T h i s female preponderance makes it unlikely that a single X-linked recessive gene defect is a frequent cause.…”

Fetal mortality in sibships of cases with neural tube defects

“…Rates of spontaneous abortion among recognized pregnancies would be, in this situation, higher than population rates, reflecting the occurrence, perhaps, of other ASB conceptions, but similar in sibships of male and of female probands, since proband sex would not be a measure of liability to ASB. A hypothesis of differential prenatal loss resulting from a mutation in an X-linked gene that controls in utero selection against ASB fetuses has been proposed by Burn & Gibbens (1979). Although the notion of differential prenatal selection is an attractive explanation of the unusual sex ratio among ASB births, the mechanism for this need not be that postulated by these authors.…”