title: Risk of vascular anomalies with Down syndrome.
abstract: OBJECTIVE
  Patients with Down syndrome have a reduced risk of developing solid tumors. This protective effect has been attributed to increased gene dosage from an additional copy of chromosome 21, and elevated expression of endostatin has been implicated. We hypothesized that vascular anomalies, including infantile hemangioma, an angiogenesis-dependent vascular tumor, and vascular malformations might be similarly inhibited in patients with Down syndrome.
  
  
  METHODS
  The Children's Hospital Boston Vascular Anomalies Center database was searched for patients with Down syndrome between 1999 and 2007. In addition, the records of patients with Down syndrome treated at Children's Hospital Boston and the National Birth Defects Center between 1985 and 2007 were reviewed to find concurrent vascular anomalies. Two-sided exact binomial tests were used to evaluate whether patients with vascular anomalies are at reduced risk for Down syndrome or if patients with Down syndrome are at less risk for vascular anomalies compared with the general population. Ninety-five-percent confidence intervals were calculated on the basis of the risk of Down syndrome (1 in 800) and vascular anomalies (1 in 22) in the general population.
  
  
  RESULTS
  Two of the 7354 patients evaluated in our vascular anomalies unit had Down syndrome. Both patients had a lymphatic malformation: one in the orbit and the other in the lower extremity. Six of the 633 patients with Down syndrome had a vascular anomaly (infantile hemangioma [n = 4] or lymphatic malformation [n = 2]). The risk of concurrent Down syndrome and vascular anomalies was different from the corresponding risk in the general population.
  
  
  CONCLUSIONS
  Patients with Down syndrome have a reduced risk of vascular anomalies compared with the general population. Elevated expression of antiangiogenic proteins may protect these patients from developing vascular anomalies, as well as solid tumors.
authors.affiliation: Vascular Anomalies Center and Department of Plastic Surgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA. arin.greene@childrens.harvard.edu
authors.forename: Arin K
authors.initials: AK
authors.lastname: Greene
authors.forename: Sendia
authors.initials: S
authors.lastname: Kim
authors.forename: Gary F
authors.initials: GF
authors.lastname: Rogers
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fishman
authors.forename: Bjorn R
authors.initials: BR
authors.lastname: Olsen
authors.forename: John B
authors.initials: JB
authors.lastname: Mulliken
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D016001:Confidence Intervals; D004314:Down Syndrome / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D011336:Probability; D012042:Registries; D012720:Severity of Illness Index; D017678:Sex Distribution; D054079:Vascular Malformations / Q000175:diagnosis* / Q000453:epidemiology*