Background The Dandy-Walker Complex (DWC) is a general description of a continuum of posterior fossa anomalies which includes: Dandy-Walker variant and the Dandy-Walker malformation. Limited data have been published on the prevalence, prenatal diagnosis, chromosomal abnormalities, prognosis and associated malformations of DWC.
Methods Data were derived from the Utah Birth Defect Network’s (UBDN) active population based surveillance system. 22 cases of DWC were ascertained by the UBDN and clinically reviewed by a pediatric dysmorphologist from a cohort of 241,416 Utah births from the years 1999–2003.
Results Of 22 cases, 17 cases were live born, 2 stillborn and 3 therapeutically aborted. 12 cases were delivered vaginally, 6 via cesarean section. 8 cases were reported hydrocephalic in addition to a DWC diagnosis. Of 17 liveborn cases, 5 died within one month of birth. Chromosomal studies were performed on 15 of 22 cases. Chromosomal case findings include triploidy (n=1), trisomy-13 (n=2), 46, XY, del (3) (q23q26.2) (n=1), and a balanced four way translocation and two-way reciprocal translocation involving chromosomes 1, 3, 4, 5 and 13 (n=1). Of note, the 2 patients with 3q aberrations both had breakpoints within a locus recently described as a candidate gene for DWC. No consanguinity was reported.
Conclusions The overall prevalence of the DWC in Utah during the years 1999–2003 was 0.91 per 10,000 births. These data represent the first known populationbased estimate of DWC prevalence. This estimate is over twice the magnitude of previous estimates. DWC can be incompatible with life. Further chromosome studies are needed to illuminate the contribution of 3q to DWC etiology.