title: Improving preimplantation genetic diagnosis for Fragile X syndrome: two new powerful single-round multiplex indirect and direct tests.
abstract: Fragile X syndrome (FraX) is caused by the expansion of an unstable CGG repeat located in the Fragile X mental retardation 1 gene (FMR1) gene. Preimplantation genetic diagnosis (PGD) can be proposed to couples at risk of transmitting the disease, that is, when the female carries a premutation or a full mutation. We describe two new single-cell, single-round multiplex PCR for indirect and direct diagnosis of FraX on biopsied embryos. These tests include five unpublished, highly heterozygous simple sequence repeats, and the co-amplification of non-expanded CGG repeats for the direct test. Heterozygosity of the new markers ranged from 69 to 81%. The mean rate of non-informative marker included in the tests was low (26% and 23% for the new indirect and direct tests, respectively). This strategy allows offering a PGD for FraX to 96% of couples requesting it in our centre. A conclusive genotype was obtained in all cells with a rate of cells presenting an allele dropout ranging from 17% for the indirect test to 26% for the direct test. The new indirect test was applied for eight PGD cycles: 32 embryos were analysed, 9 were transferred and 3 healthy babies were born. By multiplexing these highly informative markers, robustness of the diagnosis is improved and the loss of potentially healthy embryos (because they are non-diagnosed or misdiagnosed) is limited. This may increase the chances of success of couples requesting a PGD for FraX, in particular, when premature ovarian insufficiency in premutated women leads to a reduced number of embryos available for analysis.
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Kieffer
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Nicod
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Gardes
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Kastner
authors.affiliation: Laboratoire de Biologie de la Reproduction, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Becker
authors.affiliation: Laboratoire de Biologie de la Reproduction, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Celebi
authors.affiliation: Assistance Médicale à la Procréation, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Pirrello
authors.affiliation: Assistance Médicale à la Procréation, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Rongières
authors.affiliation: Laboratoire de Biologie de la Reproduction, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.|Université de Strasbourg, Strasbourg, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Koscinski
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Gosset
authors.affiliation: Laboratoire de Diagnostic Préimplantatoire, Hôpitaux Universitaires de Strasbourg, site du CMCO, Strasbourg, France.|Université de Strasbourg, Strasbourg, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Moutou
mesh_terms: D000328:Adult; D000483:Alleles; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005600:Fragile X Syndrome / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics*; D060885:Multiplex Polymerase Chain Reaction; D009154:Mutation; D011247:Pregnancy; D019836:Preimplantation Diagnosis; D016649:Primary Ovarian Insufficiency / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D059010:Single-Cell Analysis; D018911:Trinucleotide Repeats / Q000235:genetics
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human