title: Risk of fetal mosaicism when placental mosaicism is diagnosed by chorionic villus sampling.
abstract: OBJECTIVE
  Our purpose was to determine the risk of fetal mosaicism when placental mosaicism is found on chorionic villus sampling.
  
  
  METHODS
  We present a case of mosaic trisomy 22 detected on chorionic villus sampling and subsequently found in the fetus. A review of comprehensive chorionic villus sampling studies with emphasis on follow-up for fetal mosaicism was conducted.
  
  
  RESULTS
  Among 13 studies reviewed, 469 cases of placental mosaicism are presented; fetal mosaicism was found in 50 (10.7%). Factors associated with fetal mosaicism are (1) mosaicism on mesenchymal core culture and (2) type of chromosome abnormality involved--specifically, marker chromosomes (26.7%) and common autosomal trisomies (19.0%). Amniocentesis predicted fetal genotype in 93% to 100% of cases of placental mosaicism, depending on the cell type in which mosaicism was diagnosed.
  
  
  CONCLUSIONS
  Although mosaicism is usually confined to the placenta, the fetus is involved in about 10% cases. Patients should be counseled about this risk and the accuracy of follow-up amniocentesis.
authors.affiliation: Division of Reproduction Genetics, Department of Obstetrics and Gynecology, University of Tennessee, Memphis 38163, USA.
authors.forename: O P
authors.initials: OP
authors.lastname: Phillips
authors.forename: A T
authors.initials: AT
authors.lastname: Tharapel
authors.forename: J L
authors.initials: JL
authors.lastname: Lerner
authors.forename: V M
authors.initials: VM
authors.lastname: Park
authors.forename: S S
authors.initials: SS
authors.lastname: Wachtel
authors.forename: L P
authors.initials: LP
authors.lastname: Shulman
mesh_terms: D000328:Adult; D000649:Amniocentesis; D015193:Chorionic Villi Sampling; D002892:Chromosomes, Human, Pair 22; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D009030:Mosaicism; D010920:Placenta / Q000473:pathology*; D011247:Pregnancy; D012307:Risk Factors; D014314:Trisomy