Survival of fetuses with 45,X: an instructive case and an hypothesis.
The high (greater than 95%) fetal loss rate of 45,X embryos and fetuses has led to the suggestion that fetal survival with this karyotype requires the presence of mosaicism. However, in many instances, even given a "mild Ullrich-Turner syndrome" phenotype, mosaicism is not detected. In a pregnancy studied for advanced maternal age, CVS cultured cells showed 65% 45,X and 35% 46,X,r(X). After termination, 2 fetal tissues showed 95% 45,X cells. It is suggested that infants with the 45,X karyotype likely had mosaicism for a structurally abnormal X or Y chromosome during embryogenesis, but the abnormal cell line disappeared prior to birth.
Kelly
T E
TE
Division of Medical Genetics, University of Virginia School of Medicine, Charlottesville.
Ferguson
J E
JE
Golden
W
W
D000328:Adult; D000782:Aneuploidy; D002478:Cells, Cultured; D005260:Female; D005328:Fetal Viability; D006801:Humans; D007621:Karyotyping; D009030:Mosaicism; D011247:Pregnancy; D014424:Turner Syndrome / Q000235:genetics* / Q000401:mortality; D014960:X Chromosome