Dandy-Walker Syndrome

Epidemiology Incidence is approximately 1 in 25-35,000 live births. [3] It occurs slightly more frequently in females than in males. Marked variation has been shown in the genetics and aetiology. Most cases of DWS are sporadic, although familial occurence has been reported and several individuals with de novo interstitial deletions of 3q have been identified. [4] DWS may result from chromosomal anomalies or environmental factors. [5] Recognised chromosomal abnormalities associated with DWS include trisomies (trisomy 18, 13, 21 or 9) and triploidy. Recognised single gene defects associated with DWS include Walker-Warburg syndrome or Meckel's syndrome and in these cases the recurrence risk for siblings may be high. [6] Associated environmental factors include first-trimester exposure to rubella, cytomegalovirus, toxoplasmosis or warfarin. Maternal diabetes during pregnancy is also associated with increased risk. However, brain malformations associated with DWS often occur as an isolated condition and in these cases the cause is usually unknown. When the evidence suggests that there is no association with a Mendelian or chromosomal disorder then the recurrence risk is relatively low at between 1% and 5%. [7]