Trisomy 8 mosaicism: selective growth advantage of normal cells vs. growth disadvantage of trisomy 8 cells.
A fetus with trisomy 8 mosaicism was identified prenatally due to an abnormal maternal serum triple screen. Tissue samples were taken at birth to determine the level of trisomy 8 mosaicism found within embryonic and extra-embryonic tissues, rates of cell division for the two cell lines, and the effect of mosaicism on the phenotype. The level of trisomy 8 cells in blood and fibroblasts was higher than in placental tissue. Cell cycle kinetics, by incorporation of bromodeoxyuridine for 48 hr, was not significantly different between the trisomy 8 and normal cells for blood or amnion. Fluorescent in situ hybridization (FISH) using centromeric probe for chromosome 8 showed significantly more trisomy 8 in interphase vs. metaphase in lymphoblasts, umbilical cord fibroblasts, and chorion. The loss of trisomy 8 cells is not due to anaphase lag, as determined by micronuclei analysis. The similarity of cell cycle kinetics between trisomy 8 cells and normal diploid cells suggests some trisomy 8 cells are exiting the cell cycle prematurely. This growth disadvantage of trisomy 8 cells results in the appearance of growth advantage for diploid cells.
Hulley
Bonnie J
BJ
Genetics and Developmental Biology Program, West Virginia University, Morgantown, West Virginia 26506-9203, USA.
Hummel
Marybeth
M
Cook
Linda L
LL
Boyd
Brita K
BK
Wenger
Sharon L
SL
D000650:Amnion / Q000166:cytology; D001773:Blood Cells / Q000166:cytology; D002453:Cell Cycle / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002478:Cells, Cultured; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D005333:Fetus; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D009030:Mosaicism / Q000235:genetics*; D014314:Trisomy; D014470:Umbilical Cord / Q000166:cytology