title: Two cases of confined placental mosaicism for chromosome 4, including one with maternal uniparental disomy.
abstract: Two cases of trisomy 4 mosaicism are reported including one with molecularly confirmed uniparental disomy (UPD) of chromosome 4. Cytogenetic analysis of a chorionic villus sample (CVS) in Case 1 showed complete trisomy 4 in trophoblast and diploidy in chorionic stroma. Amniotic fluid analysis demonstrated a 46,XX complement. After intrauterine fetal death at 30 weeks, molecular analysis confirmed the presence of trisomy 4 of maternal meiotic origin, while fetal tissues showed maternal UPD for chromosome 4. Cultured CVS in Case 2 revealed trisomy 4 in 2/30 cells analyzed. This pregnancy resulted in a healthy livebirth with biparental inheritance of chromosome 4. Molecularly confirmed UPD4 has not been previously reported, and therefore, although the adverse outcome in Case 1 is likely due to the trisomy 4 in the placenta, an imprinting effect associated with UPD4 cannot be excluded.
authors.affiliation: Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.
authors.forename: B D
authors.initials: BD
authors.lastname: Kuchinka
authors.forename: I J
authors.initials: IJ
authors.lastname: Barrett
authors.forename: G
authors.initials: G
authors.lastname: Moya
authors.forename: J M
authors.initials: JM
authors.lastname: Sánchez
authors.forename: S
authors.initials: S
authors.lastname: Langlois
authors.forename: S L
authors.initials: SL
authors.lastname: Yong
authors.forename: D K
authors.initials: DK
authors.lastname: Kalousek
authors.forename: W P
authors.initials: WP
authors.lastname: Robinson
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D015193:Chorionic Villi Sampling; D002894:Chromosomes, Human, Pair 4; D005260:Female; D005313:Fetal Death; D006580:Genetic Carrier Screening; D005865:Gestational Age; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D009030:Mosaicism; D010920:Placenta; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis; D014178:Translocation, Genetic; D014314:Trisomy