Background: Hydrocephalus caused by excessive liquor production due to choroid plexus hyperplasia is a rare condition that may necessitate unusual treatment paradigms. It can be seen in trisomy 9p where coexisting congenital heart disease additionally may complicate the therapeutic approach as illustrated in the current case report.
Case Presentation: At 20 months of age, a Caucasian girl with trisomy 9 and family history of an older brother and twin sister having the same syndrome displayed sign of congenital hydrocephalus due to increasing head circumference.