title: Could Digital PCR Be an Alternative as a Non-Invasive Prenatal Test for Trisomy 21: A Proof of Concept Study.
abstract: NIPT for fetal aneuploidy by digital PCR has been hampered by the large number of PCR reactions needed to meet statistical requirements, preventing clinical application. Here, we designed an octoplex droplet digital PCR (ddPCR) assay which allows increasing the number of available targets and thus overcomes statistical obstacles.
  
  
  
  After technical optimization of the multiplex PCR on mixtures of trisomic and euploid DNA, we performed a validation study on samples of plasma DNA from 213 pregnant women. Molecular counting of circulating cell-free DNA was performed using a mix of hydrolysis probes targeting chromosome 21 and a reference chromosome.
  
  
  
  The results of our validation experiments showed that ddPCR detected trisomy 21 even when the sample's trisomic DNA content is as low as 5%. In a validation study of plasma samples from 213 pregnant women, ddPCR discriminated clearly between the trisomy 21 and the euploidy groups.
  
  
  
  Our results demonstrate that digital PCR can meet the requirements for non-invasive prenatal testing of trisomy 21. This approach is technically simple, relatively cheap, easy to implement in a diagnostic setting and compatible with ethical concerns regarding access to nucleotide sequence information. These advantages make it a potential technique of choice for population-wide screening for trisomy 21 in pregnant women.
authors.affiliation: INSERM, U1016, Institut Cochin, CNRS UMR8104, Université Paris Descartes, Paris, France.|Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Laïla Allach
authors.initials: LA
authors.lastname: El Khattabi
authors.affiliation: Fédération de Génétique, CHI de Poissy St Germain, Poissy, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Rouillac-Le Sciellour
authors.affiliation: Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Le Tessier
authors.affiliation: Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Armelle
authors.initials: A
authors.lastname: Luscan
authors.affiliation: Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Coustier
authors.affiliation: Centre d'Epidémiologie Clinique, Hôtel Dieu, Paris, France.
authors.forename: Raphael
authors.initials: R
authors.lastname: Porcher
authors.affiliation: Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Rakia
authors.initials: R
authors.lastname: Bhouri
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Hôpital Cochin, Laboratoire de Biochimie et Génétique Moléculaire, Paris, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Nectoux
authors.affiliation: Fédération de Génétique, CHI de Poissy St Germain, Poissy, France.|GIG, Faculté des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, Montigny le bretonneux, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Sérazin
authors.affiliation: Département d'Obstétrique et de Gynécologie, CHI de Poissy St Germain, Poissy, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Quibel
authors.affiliation: Service de Gynécologie-Obstétrique, Hôpital Louis Mourier, Hôpitaux Universitaires Paris-Nord Val de Seine, Colombes, France; Université Paris-Diderot, Paris, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Mandelbrot
authors.affiliation: Département d'Obstétrique et de Gynécologie, Hôpital Cochin-Maternité Port-Royal, Université Paris Descartes, Paris, France.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Tsatsaris
authors.affiliation: Fédération de Génétique, CHI de Poissy St Germain, Poissy, France.|GIG, Faculté des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, Montigny le bretonneux, France.
authors.forename: François
authors.initials: F
authors.lastname: Vialard
authors.affiliation: INSERM, U1016, Institut Cochin, CNRS UMR8104, Université Paris Descartes, Paris, France.|Laboratoire de Cytogénétique, Hôpital Cochin-Maternité Port-Royal, AP-HP, Paris, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Dupont
mesh_terms: D002891:Chromosomes, Human, Pair 21 / Q000235:genetics; D004247:DNA / Q000097:blood; D015342:DNA Probes / Q000378:metabolism; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D011296:Prenatal Diagnosis / Q000379:methods*; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D015342:DNA Probes; D004247:DNA