title: Mosaic vs. nonmosaic trisomy 9: report of a liveborn infant evaluated by fluorescence in situ hybridization and review of the literature.
abstract: We report on a newborn infant with multiple congenital anomalies and apparent nonmosaic trisomy 9 in the blood (by conventional cytogenetic studies) who died shortly after birth. Clinical observations at birth and autopsy are compared with phenotypes of mosaic and nonmosaic trisomy 9 cases reported previously. Unlike the initial cytogenetic analysis, fluorescence in situ hybridization (FISH) studies of metaphase and interphase blood cells and skin fibroblasts detected the presence of euploid and trisomy 9 cells. These results suggest that earlier reports of trisomy 9, which relied on conventional chromosome analysis of a few metaphase cells and/or only one tissue type, may not have excluded mosaicism, and that trisomy 9 may be viable only in the mosaic state.
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Cantú
authors.forename: D J
authors.initials: DJ
authors.lastname: Eicher
authors.forename: G S
authors.initials: GS
authors.lastname: Pai
authors.forename: C J
authors.initials: CJ
authors.lastname: Donahue
authors.forename: R A
authors.initials: RA
authors.lastname: Harley
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D000328:Adult; D001344:Autopsy; D002899:Chromosomes, Human, Pair 9; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D007231:Infant, Newborn; D008297:Male; D009030:Mosaicism; D014314:Trisomy