title: Low-level mosaicism for both trisomy 15 and monosomy-X in amniotic fluid cells confirmed in fetal tissues.
abstract: We report here a case of true fetal mosaicism for both trisomy 15 and monosomy-X; the aberrant cell lines were initially detected at amniocentesis as low-level mosaicism (trisomy 15) and multiple-cell pseudo-mosaicism (monosomy-X). In the fetal lymphocytes, only metaphases with a normal chromosome complement were observed. After termination of the pregnancy, various fetal biopsies revealed both trisomy 15 and monosomy-X mosaicism, whereas, at autopsy, no external or internal abnormalities could be detected in the fetus. The karyotype can be described as 45,X[15]/47,XY,+15[3]/46,XY[27]. Our results implicate that an additional amniocentesis could be more helpful than fetal blood sampling in predicting the fetal karyotype after diagnosis of chromosome mosaicism at amniocentesis.
authors.affiliation: Academic Medical Centre, University of Amsterdam, Department of Human Genetics, The Netherlands. hansson@ruly46.medfac.leidenuniv.nl
authors.forename: K
authors.initials: K
authors.lastname: Hansson
authors.forename: W M
authors.initials: WM
authors.lastname: Poelma
authors.forename: H A
authors.initials: HA
authors.lastname: Zondervan
authors.forename: N J
authors.initials: NJ
authors.lastname: Leschot
mesh_terms: D000328:Adult; D000649:Amniocentesis; D002478:Cells, Cultured; D002884:Chromosomes, Human, Pair 15; D017218:Cordocentesis; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005865:Gestational Age; D006801:Humans; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D009006:Monosomy; D009030:Mosaicism; D011247:Pregnancy; D014314:Trisomy; D014960:X Chromosome