title: Absent fetal nasal bone: what does it mean for the euploid fetus?
abstract: OBJECTIVE
  Our purpose was to review the outcomes of singleton pregnancies in which an absent nasal bone was noted on first- or second-trimester sonography and aneuploidy was not present.
  
  
  METHODS
  We identified singleton pregnancies from 2005 to 2011 in which an absent nasal bone was noted on sonography, aneuploidy was excluded, and newborn examinations were available for review. Sonographic reports were reviewed for anomalies, growth, and amniotic fluid volume. Newborn records were reviewed for physical examinations, complications, and radiologic or genetic tests.
  
  
  RESULTS
  We identified 142 fetuses with a sonographic appearance of an absent nasal bone. We excluded 52 cases with aneuploidy and 33 in which newborn examination information was unavailable. Fifty-seven cases met inclusion criteria. For 3 euploid fetuses with an absent nasal bone on sonography, the presence of additional anomalies on second-trimester sonography ultimately signaled an adverse outcome: the presence of multiple congenital anomalies, a microdeletion syndrome, and a specific genetic diagnosis.
  
  
  CONCLUSIONS
  All cases with adverse outcomes had additional prenatal sonographic findings. For the remainder, normal newborn examination findings provide some reassurance, especially in the setting of otherwise normal second-trimester sonographic findings. A microarray as a test for microdeletion and duplication syndromes in this situation could be considered.
authors.affiliation: Brigham and Women's Hospital, 75 Francis St, Boston, MA 02118 USA. sdukhovny@partners.org.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Dukhovny
authors.forename: Louise
authors.initials: L
authors.lastname: Wilkins-Haug
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Shipp
authors.forename: Carol B
authors.initials: CB
authors.lastname: Benson
authors.forename: Anjali J
authors.initials: AJ
authors.lastname: Kaimal
authors.forename: Rosemary
authors.initials: R
authors.lastname: Reiss
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000235:genetics*; D000782:Aneuploidy; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D009295:Nasal Bone / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000196:embryology*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data*
keywords: absent nasal bone; euploid fetus; prenatal diagnosis