Truncus arteriosus and facial dysmorphism.

Facial features of infants with truncus arteriosus were photographed and reviewed. Anomalies included hypertelorism, low set ears, micrognathia, down-slanting palpebral fissures, short philtrum and small mouths. Associated cardiovascular defects were interrupted aortic arch, double aortic arch, right aortic arch and aberrant brachiocephalic vessels. Potential teratogenic factors included maternal diabetes, syphilis, alcohol ingestion, carbimazole therapy and infant chromosomal anomalies. The facial features, together with the rare cardiac abnormalities of truncus arteriosus and aortic arch defects are similar to those described in Di George syndrome (defect of fourth branchial arch and derivatives of third and fourth pharyngeal pouches). However none of these patients had symptomatic hypocalcaemia or absence of the thymus. It is concluded that this association of truncus arteriosus, aortic arch abnormalities and facial anomalies involves first and fourth branchial arch maldevelopment, and indicates embryological insult between the fourth and seventh weeks of gestation.