Dandy–Walker syndrome

ObjectivesDandy–Walker syndrome is a rare disorder characterised by complete or partial agenesis of the vermis, cystic dilatation of the fourth ventricle and an enlarged posterior fossa. The precise aetiology is unknown, although there have been reports of associations with risk factors like maternal virus infections (rubella, toxoplasma, and cytomegalovirus) and alcohol consumption. The reported incidence varies between one per 2500 births to one per 100,000 births. This huge difference may be due to the limited published case series, as most of the available data are sporadic case reports or series.MethodsA retrospective review was conducted of medical records of neonates with Dandy–Walker syndrome admitted to the neonatal intensive care unit of a university hospital between January 2001 and December 2010.ResultsEight infants with Dandy–Walker syndrome were admitted during the study period, giving an overall incidence of 1/400 live births. The female-to-male ratio was 1.7:1 (one infant had ambiguous gender but was later found to be male). The mean gestational age was 39.0 weeks (range, 36–40 weeks), and the mean birth weight was 2716 g (range, 1965–3335 g). The syndrome was diagnosed in half the infants prenatally. All infants had associated hydrocephalus, and five had other neurological anomalies; extra-cranial anomalies were seen in 50% of infants. All infants survived to discharge.ConclusionAlthough many of our results were consistent with published data, the incidence of Dandy–Walker syndrome in our study was much higher than any reported previously. Further research is required to elucidate this unexpected finding.