Congenital absence of the ductus venosus: with direct connection between the umbilical vein and the distal inferior vena cava

Umbilical vessel catheterization in a neonate with Noonan's syndrome disclosed a unique developmental anomaly of the umbilical vein. There was no evidence of a ductus venosus nor any connection between the vein and the portal hepatic venous system. The umbilical vein instead entered the inferior vena cava directly at the level of the iliac veins. There was a single umbilical artery.