Twin-to-twin transfusion syndrome, vein of galen malformation, and transposition of the great arteries in a pair of monochorionic twins: coincidence or related association?

The pathogenetic mechanisms leading to the development of congenital heart disease and congenital intracranial arteriovenous malformation are still unclear. We report on a monochorionic twin pregnancy with twin-to-twin transfusion syndrome (TTTS), in which vein of Galen malformation (VGM) was diagnosed in the donor twin and transposition of the great arteries (TGA) in the recipient twin. The development of TTTS, VGM, and TGA in a single monochorionic pregnancy could be pure coincidence, but there might also be a causative link. We discuss the possible contribution of genetic factors, fetal flow fluctuations, vascular endothelial growth factors, and the process of twinning itself to the development of these congenital anomalies.