title: Discordant results between fetal karyotyping and non-invasive prenatal testing by maternal plasma sequencing in a case of uniparental disomy 21 due to trisomic rescue.
abstract: Uniparental disomy (UPD) is an uncommon chromosome condition, but UPD involving chromosome 21 is rarely reported. We reported here a case who had first trimester screening test for Down syndrome, chorionic villus sampling for fetal karyotyping, quantitative fluorescence polymerase chain reaction (QF-PCR), as well as non-invasive prenatal testing (NIPT) by maternal plasma sequencing. There were discordant results between fetal karyotyping and NIPT due to UPD 21combined with confined placental mosaicism of trisomy 21. This demonstrated that it is possible to detect placental mosaicism by NIPT, but further studies are required to confirm its sensitivity. Therefore, all positive NIPT results must be confirmed by conventional invasive test and karyotyping. QF-PCR has the additional benefit in diagnosing UPD.
authors.affiliation: Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China.
authors.forename: Min
authors.initials: M
authors.lastname: Pan
authors.forename: Fa Tao
authors.initials: FT
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Fu Man
authors.initials: FM
authors.lastname: Jiang
authors.forename: Dong Zhi
authors.initials: DZ
authors.lastname: Li
authors.forename: Tze Kin
authors.initials: TK
authors.lastname: Lau
authors.forename: Can
authors.initials: C
authors.lastname: Liao
mesh_terms: D000328:Adult; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D004303:Dosage Compensation, Genetic / Q000502:physiology; D005260:Female; D006801:Humans; D007621:Karyotyping / Q000379:methods*; D009030:Mosaicism; D011247:Pregnancy / Q000097:blood; D011296:Prenatal Diagnosis / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics; D024182:Uniparental Disomy / Q000175:diagnosis* / Q000235:genetics