Mosaic vs. nonmosaic trisomy 9: report of a liveborn infant evaluated by fluorescence in situ hybridization and review of the literature.
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.
Cantú
E S
ES
Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston 29425, USA.
Eicher
D J
DJ
Pai
G S
GS
Donahue
C J
CJ
Harley
R A
RA
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