title: Clinical applications of fetal sex determination in maternal blood in a preimplantation genetic diagnosis centre.
abstract: BACKGROUND
  Couples with a risk of transmitting X-linked diseases who are included in a preimplantation genetic diagnosis (PGD) programme need early and rapid fetal sex determination in two situations. The first situation is for the control of embryo sexing after PGD and the second situation is for those couples having a spontaneous pregnancy before the start of their PGD cycle. Among invasive techniques, chorionic villus sampling is the earliest procedure for fetal sex determination and molecular analysis of X-linked genetic disorders during the first trimester but it is associated with a risk of fetal loss. Non-invasive procedures such as ultrasound examination allow reliable fetal sex determination only during the second trimester. Reliable fetal sex determination can now be realised by using SRY gene amplification in maternal blood.
  
  
  RESULTS
  We report the use of fetal sex determination from maternal serum as a diagnostic tool for the control of embryo sexing (two cases) and to manage spontaneous pregnancies in couples included in a PGD programme for X-linked diseases (five cases). Fetal sex determination using SRY gene amplification in maternal serum were in complete concordance with fetal sex observed by cytogenetic analysis or ultrasound examination and at birth. This novel strategy allowed the PGD results to be controlled precociously and avoided the performance of invasive procedures in four cases of female fetus.
  
  
  CONCLUSIONS
  This rapid fetal sex determination during the first trimester provides advantages to both clinicians and patients in a PGD centre.
authors.affiliation: Service de Biologie et Génétique de la Reproduction, Hôpital Antoine Béclère, 92140 Clamart, France. gerard.tachdhian@abc.ap-hop-paris.fr
authors.forename: Gérard
authors.initials: G
authors.lastname: Tachdjian
authors.forename: Nelly
authors.initials: N
authors.lastname: Frydman
authors.forename: Franciois
authors.initials: F
authors.lastname: Audibert
authors.forename: Pierre
authors.initials: P
authors.lastname: Ray
authors.forename: Violaine
authors.initials: V
authors.lastname: Kerbrat
authors.forename: Pauline
authors.initials: P
authors.lastname: Ernault
authors.forename: René
authors.initials: R
authors.lastname: Frydman
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Costa
mesh_terms: D020732:Cytogenetic Analysis; D005260:Female; D005600:Fragile X Syndrome / Q000175:diagnosis; D024282:Genes, sry; D006801:Humans; D016133:Polymerase Chain Reaction; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First; D019836:Preimplantation Diagnosis; D012732:Sex Determination Analysis; D016216:Ultrasonography, Prenatal