title: Prenatal detection of fetal triploidy from cell-free DNA testing in maternal blood.
abstract: OBJECTIVE
  To investigate potential performance of cell-free DNA (cfDNA) testing in maternal blood in detecting fetal triploidy.
  
  
  METHODS
  Plasma and buffy coat samples obtained at 11-13 weeks' gestation from singleton pregnancies with diandric triploidy (n=4), digynic triploidy (n=4), euploid fetuses (n=48) were sent to Natera, Inc. (San Carlos, Calif., USA) for cfDNA testing. Multiplex polymerase chain reaction amplification of cfDNA followed by sequencing of single nucleotide polymorphic loci covering chromosomes 13, 18, 21, X, and Y was performed. Sequencing data were analyzed using the NATUS algorithm which identifies copy number for each of the five chromosomes.
  
  
  RESULTS
  cfDNA testing provided a result in 44 (91.7%) of the 48 euploid cases and correctly predicted the fetal sex and the presence of two copies each of chromosome 21, 18 and 13. In diandric triploidy, cfDNA testing identified multiple paternal haplotypes (indicating fetal trisomy 21, trisomy 18 and trisomy 13) suggesting the presence of either triploidy or dizygotic twins. In digynic triploidy the fetal fraction corrected for maternal weight and gestational age was below the 0.5th percentile.
  
  
  CONCLUSIONS
  cfDNA testing by targeted sequencing and allelic ratio analysis of single nucleotide polymorphisms covering chromosomes 21, 18, 13, X, and Y can detect diandric triploidy and raise the suspicion of digynic triploidy.
authors.affiliation: Harris Birthright Research Centre of Fetal Medicine, King's College Hospital, London, UK.
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
authors.forename: Argyro
authors.initials: A
authors.lastname: Syngelaki
authors.forename: Maria
authors.initials: M
authors.lastname: del Mar Gil
authors.forename: Maria Soledad
authors.initials: MS
authors.lastname: Quezada
authors.forename: Yana
authors.initials: Y
authors.lastname: Zinevich
mesh_terms: D000328:Adult; D002474:Cell-Free System / Q000502:physiology; D004247:DNA / Q000235:genetics*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis / Q000235:genetics; D006801:Humans; D008297:Male; D062145:Maternal Serum Screening Tests / Q000379:methods*; D008875:Middle Aged; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D057885:Triploidy; D055815:Young Adult
chemical_list: D004247:DNA