title: Cytogenetic and histological features of a human embryo with homogeneous chromosome 8 trisomy.
abstract: BACKGROUND
  Homogeneous and complete trisomy 8 is extremely rare. With one recent neonatal exception, all reported cases have been mosaic, due to mitotic non-disjunction during early zygotic development. We report a case of chromosome 8 trisomy in a human embryo examined at Carnegie stage 11 (25 days post-fertilization). It presented severe cardiovascular and central nervous system malformations.
  
  
  METHODS
  The unusual bifid heart in this embryo spurred a detailed histological examination, karyotyping of a chorionic villus sample and subsequent FISH on inter-phase nuclei of intra-embryonic sections.
  
  
  RESULTS
  Trophoblast cells had a karyotype of 47,XX, +8. Within the embryo proper, FISH demonstrated that the trisomy 8 was homogeneous in embryonic as well as extra-embryonic tissues. FQ-PCR supports a meiosis I origin of non-disjunction. In sections, the pharyngeal arches (including cardiac outflow tract), forebrain, mesonephros and liver were absent. Somites and yolk sac blood vessels were irregularly shaped.
  
  
  CONCLUSIONS
  We show that homogeneous, intra-embryonic trisomy 8 is compatible with implantation and early human development. Molecular pathways that may be compromised and their impact on organogenesis are discussed.
authors.affiliation: INSERM U781, Hôpital Necker - Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex 15, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Golzio
authors.forename: Jessica
authors.initials: J
authors.lastname: Guirchoun
authors.forename: Catherine
authors.initials: C
authors.lastname: Ozilou
authors.forename: Sophie
authors.initials: S
authors.lastname: Thomas
authors.forename: Géraldine
authors.initials: G
authors.lastname: Goudefroye
authors.forename: Nicole
authors.initials: N
authors.lastname: Morichon-Delvallez
authors.forename: Michel
authors.initials: M
authors.lastname: Vekemans
authors.forename: Tania
authors.initials: T
authors.lastname: Attié-Bitach
authors.forename: Heather C
authors.initials: HC
authors.lastname: Etchevers
mesh_terms: D000015:Abnormalities, Multiple; D000025:Abortion, Eugenic; D018376:Cardiovascular Abnormalities / Q000235:genetics* / Q000473:pathology; D015193:Chorionic Villi Sampling; D002898:Chromosomes, Human, Pair 8; D004622:Embryo, Mammalian / Q000002:abnormalities*; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D009421:Nervous System Malformations / Q000235:genetics* / Q000473:pathology; D032681:Spectral Karyotyping; D014314:Trisomy; D014327:Trophoblasts / Q000473:pathology
chemical_list: D005819:Genetic Markers