The mystery of nuchal translucency

See Article Image. Further experience with the phenomenon of increased nuchal translucency, demonstrated that when the chromosomes were normal, there was an increased incidence of other fetal malformations, in particular congenital cardiac disease, but also apparently unrelated defects, such as skeletal anomalies, diaphragmatic hernia, and an ever-increasing list of genetic syndromes.4 At first sight, it appears difficult to understand any possible association between such unrelated defects as cardiac and skeletal malformations. Later experimentation on pregnant rats using the poison nitrofen, at a critical period of embryological development, led to the induction of diaphragmatic hernia or congenital cardiac disease7 in one study, and skeletal anomalies in another.8 Bisdiamine, another poison extensively investigated in particular by Japanese workers, is known to induce anomalies of the ventricular outflow tracts in rats.9 The mode of action of both these poisons is through the inhibition of retinal dehydrogenase-2, the enzyme which forms retinoic acid from retinaldehyde, or vitamin A.10 A recent paper demonstrated a low level of retinol at birth in neonates with diaphragmatic hernia.11 It might be of interest to test levels of retinol in neonates with congenital cardiac malformations.