3 INFANTS OF DIABETIC MOTHERS WITH MALFORMATIONS OF LEFT-RIGHT ASYMMETRY - FURTHER EVIDENCE FOR THE ETIOLOGIC ROLE OF DIABETES IN THIS MALFORMATION SPECTRUM

We report three babies with malformations of left-right asymmetry who were born to mothers with insulin-dependent diabetes mellitus. One inf ant had left isomerism and asplenia, one had polysplenia, and the thir d baby had situs inversus with a neural tube defect. Defects of left-r ight asymmetry have not previously been well recognized as part of the spectrum of anomalies associated with maternal diabetes. We believe t hat the association of maternal diabetes with these malformations in t he infants is not coincidental, and that diabetes mellitus has an aeti ological role in this spectrum of abnormalities. Two of the mothers ha d elevated HbA(1C) levels in pregnancy, and thus the malformations may be due to poor glycaemic control, although other teratogenic mechanis ms associated with diabetes cannot be excluded. Finally, to our knowle dge, the finding of left isomerism with asplenia (part of the spectrum of right isomerism) is rare. The occurrence Of both forms of isomeris m in different parts of the same body supports the model of random dev elopment of laterality following the interruption of normal developmen tal processes.