Prenatal diagnosis of topsy-turvy heart.

We describe two siblings of consanguineous parents with a prenatal diagnosis of a currently unique form of congenital cardiac disease characterized by superior-inferior atrial and ventricular arrangement, concordant atrioventricular and ventriculo-arterial connections with normal arterial relationships, and a bizarre topography of the ventricular outlets, with the arterial poles being displaced posterior-inferiorly within the thorax. The abnormally low position of the aortic arch resulted in elongation and stretching of the airways, with severe compression of the trachea and left main bronchus in the surviving sibling. The finding of the same rare abnormality in a son and a daughter born to consanguineous parents supports a single gene disorder with a recessive mode of inheritance.