Atrioventricular septal defect with pulmonary atresia in DiGeorge anomaly: expansion of the cardiac phenotype

Association of DiGeorge anomaly and caudal dysplasia sequence in a neonate born to a diabetic mother

AIM/OBJECTIVE

Several studies have demonstrated a significantly increased risk of specific patterns of congenital anomalies in infants born to diabetic mothers. In particular, caudal dysplasia sequence has been linked to pregnancy complicated by maternal diabetes. In addition, several cases of infants born to diabetic mothers presenting with features of DiGeorge anomaly have been reported. Infants with DiGeorge anomaly can display additional manifestations within the spectrum of caudal dysplasia sequence, including vertebral anomalies and renal agenesis.

METHODS

We report a neonate presenting with the co-occurrence of features of both DiGeorge anomaly and caudal dysplasia sequence, born to a mother with poorly controlled insulin-dependent diabetes.

RESULTS

The patient was affected by truncus arteriosus type A1 and hypertrophic cardiomyopathy.

CONCLUSION

Maternal diabetes can cause a spectrum of manifestations, expressing with isolated DiGeorge anomaly or caudal dysplasia sequence, with intermediate phenotypes or with the co-occurrence of both the congenital anomalies in the same patient. The present observations argue for a feasible link between truncus arteriosus with hypertrophic cardiomyopathy, DiGeorge anomaly, and maternal diabetes.

Malformations in offspring of diabetic rats: morphometric analysis of neural crest-derived organs and effects of maternal vitamin E treatment

BACKGROUND

We have previously reported on a malformation-prone Sprague-Dawley rat substrain (U), which presents a high frequency of micrognathia in the offspring of diabetic mothers. This malformation is related to impaired development of the cranial neural crest cells (NCC); the defect may be prevented by antioxidative treatment of the mother.

METHODS

We have therefore investigated whether fetuses of diabetic rats display other malformations associated with altered cranial NCC development and whether maternal vitamin E supplementation may affect such malformations.

RESULTS

Fetuses of diabetic rats showed low-set external ears, severely malformed Meckel's cartilage, small thyroid and thymus, and absence of parathyroid glands. Cardiac anomalies were frequently observed, including rightward displacement of the aorta, double outlet right ventricle (DORV), persistent truncus arteriosus (PTA) combined with ventricular septal defects due to a malaligned outlet septum. The malformations in the outflow tract included abnormalities of the great arteries; right-sided aortic arch/descending aorta, and double aortic arches. These defects tended to occur together within individual fetuses. Maternal dietary treatment with 2% vitamin E markedly reduced the severity of the malformations.

CONCLUSIONS

The phenotypic appearance of these defects is strikingly similar to the DiGeorge anomaly in humans, which has been found in children of diabetic mothers together with an overrepresentation of PTA and DORV. The malformations associated with defective NCC development in the offspring of diabetic U rats show several morphological similarities to those in humans; hence the teratogenic mechanisms may be similar and accessible for study.

Pathogenesis of diabetes-induced congenital malformations

The increased rate of fetal malformation in diabetic pregnancy represents both a clinical problem and a research challenge. In recent years, experimental and clinical studies have given insight into the teratological mechanisms and generated suggestions for improved future treatment regimens. The teratological role of disturbances in the metabolism of inositol, prostaglandins, and reactive oxygen species has been particularly highlighted, and the beneficial effect of dietary addition of inositol, arachidonic acid and antioxidants has been elucidated in experimental work. Changes in gene expression and induction of apoptosis in embryos exposed to a diabetic environment have been investigated and assigned roles in the teratogenic processes. The diabetic environment appears to simultaneously induce alterations in several interrelated teratological pathways. The complex pathogenesis of diabetic embryopathy has started to unravel, and future research efforts will utilize both clinical intervention studies and experimental work that aim to characterize the human applicability and the cell biological components of the discovered teratological mechanisms.