title: [Down-Turner syndrome (45,X/47,XY,+21): case report and review].
abstract: We report the case of a 3-yr-old boy with Down-Turner mosaicism and review the previous reports of Down-Turner syndrome with documented karyotyping and clinical features. The patient showed clinical features of Down syndrome without significant stigma of Turner syndrome. Cytogenetic analysis of peripheral blood preparations by using G-banding revealed mosaicism with 2 cell lines (45,X[29]/47,XY,+21[4]). FISH analysis revealed that 87.5% of the cells had monosomy X karyotype and 12.5% of the cells had XY karyotype; trisomy 21 was only detected in the Y-positive cells. We suggest that additional cells should be analyzed and molecular genetic studies should be conducted to rule out double aneuploidy when karyotypes with sex chromosome aneuploidies and mosaicism are encountered, as in our case of Down syndrome mosaic with sex chromosome aneuploidy.
authors.affiliation: Department of Laboratory Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.
authors.forename: Sook Won
authors.initials: SW
authors.lastname: Ryu
authors.forename: Goeun
authors.initials: G
authors.lastname: Lee
authors.forename: Cheong Soon
authors.initials: CS
authors.lastname: Baik
authors.forename: Sung Han
authors.initials: SH
authors.lastname: Shim
authors.forename: Jin Tack
authors.initials: JT
authors.lastname: Kim
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Kyung A
authors.initials: KA
authors.lastname: Lee
mesh_terms: D000782:Aneuploidy; D002675:Child, Preschool; D002871:Chromosome Banding; D002891:Chromosomes, Human, Pair 21; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D004314:Down Syndrome / Q000150:complications / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D014314:Trisomy; D014424:Turner Syndrome / Q000150:complications / Q000235:genetics*