title: [Trisomy 21 by isochromosome: a case report of true false negative of chorionic villi sampling].
abstract: We report a rare case of true false negative of chorionic villi sampling for a child with Down syndrome. A chorionic villi sampling was performed for a nuchal translucency at the first trimester. The karyotype was 46,XX for the short and the long-term culture. Because of facial dysmorphy and cardiopathy to the child, a karytoype was proposed. This postnatal karyotype showed a trisomy 21, by isochromosome 46,XX,i(21)(q10). We expose the mechanism of true false negative of chorionic villi sampling, and particularly the role of isochromosome in this case.
authors.affiliation: Service de gynécologie-obstétrique, hôpital de la Croix-Rousse, hospices civils de Lyon, 103, grande rue de la Croix-Rousse, 69317 Lyon cedex 04, France. jonath.caloone@hotmail.fr
authors.forename: J
authors.initials: J
authors.lastname: Caloone
authors.forename: D
authors.initials: D
authors.lastname: Sanlaville
authors.forename: A
authors.initials: A
authors.lastname: Fichez
authors.forename: C
authors.initials: C
authors.lastname: Abel
authors.forename: C
authors.initials: C
authors.lastname: Huissoud
authors.forename: R-C
authors.initials: RC
authors.lastname: Rudigoz
mesh_terms: D015193:Chorionic Villi Sampling; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D018404:Isochromosomes; D011247:Pregnancy; D055815:Young Adult