Evidence of a second gamete fusion after the first cleavage of the zygote in a 47,XX,+18/70,XXX,+18 mosaic. A remarkable diploid-triploid discrepancy after CVS.
A 70,XXX,+18 karyotype was found by chorionic villus sampling, while the fetal fibroblast culture of the affected fetus revealed a 47,XX,+18 karyotype. From several possible mechanisms, we assume that a second gamete fusion occurred after the first cell division of the zygote. According to this interpretation, the mosaicism arose in very early pregnancy (at the two-cell stage). This discrepancy can therefore be explained by selection pressure, due to the differentiation processes in the embryonic tissues.
Department of Human Genetics, State University of Groningen, The Netherlands.
J H
JH
Tuerlings
A S
AS
Breed
R
R
Vosters
G J
GJ
Anders
D000328:Adult; D015193:Chorionic Villi Sampling; D004171:Diploidy; D005260:Female; D006801:Humans; D007621:Karyotyping; D008423:Maternal Age; D009030:Mosaicism; D011003:Ploidies; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis