title: Persistence of a monosomic cell line in a fetus with mosaic trisomy 8.
abstract: We report on a fetus presenting with an increased nuchal translucency, in which chorionic villus sampling led to the diagnosis of mosaic trisomy 8. Ultrasound scan performed at 15(+6) weeks revealed bilateral cleft lip and palate, flat facial profile, and arrhinia. Pregnancy was terminated at 16(+6); postmortem examination showed additional findings including hypospadias, bilateral renal dysplasia, and focal portal fibrosis of the liver. In order to confirm the presence of trisomy 8, FISH analysis was performed in abnormal renal and hepatic tissue, which, unexpectedly, showed a higher fraction of cells with only one fluorescent probe signal (43% and 23%, respectively), if compared with normal fetal liver and kidney (3-10%). This finding is consistent with the survival in this fetus of a monosomic cell line after mitotic non-disjunction, which is in contrast with what is generally thought about mosaic trisomy genesis. We hypothesize that the possible persistence of the monosomic cell line, in addition to the variable distribution of aneuploid cells in the body tissues, could explain the high heterogeneity of mosaic trisomy 8 phenotype.
authors.affiliation: Unit of Medical Genetics, Policlinico Sant'Orsola-Malpighi, University of Bologna, Bologna, Italy. daniela.turchetti@unibo.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Turchetti
authors.forename: Eva
authors.initials: E
authors.lastname: Pompilii
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Magrini
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Bonasoni
authors.forename: Maria Carla
authors.initials: MC
authors.lastname: Pittalis
authors.forename: Maria
authors.initials: M
authors.lastname: Segata
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pession
authors.forename: Donatella
authors.initials: D
authors.lastname: Santini
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Pilu
authors.forename: Marco
authors.initials: M
authors.lastname: Seri
mesh_terms: D059786:Abnormal Karyotype; D000028:Abortion, Induced; D000328:Adult; D001344:Autopsy; D015193:Chorionic Villi Sampling; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics; D002972:Cleft Palate / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005333:Fetus / Q000473:pathology; D006801:Humans; D007021:Hypospadias / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D017404:In Situ Hybridization, Fluorescence; D007668:Kidney / Q000473:pathology; D008099:Liver / Q000473:pathology; D008297:Male; D009006:Monosomy / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D009030:Mosaicism; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D014314:Trisomy / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology