Focal segmental glomerulosclerosis in patients after Fontan operation: is this a Fontan-associated renal disease?

Despite acceptable survival for Fontan operation, there are concerns about late complications affecting the major organs. We herein present two cases of adults after Fontan operation who developed focal segmental glomerulosclerosis. These cases suggest that focal segmental glomerulosclerosis is owing to haemodynamic incompetence associated with Fontan operation, including congestion, hypoxia, and hyperviscosity, which may be called Fontan-associated renal disease.