Confined placental mosaicisms and uniparental disomy
- Univ. of British Columbia, Vancouver (Canada); and others
Approximately 2% of pregnancies studied with chorionic villous sampling (CVS) show confined placental mosaicism (CPM) which persists to term in 50-70% of cases. An increased frequency of complications, such as intrauterine fetal growth restriction or intrauterine death, is observed in these pregnancies. As trisomic zygote rescue is a common mechanism responsible for CPM, fetal uniparental disomy (UPD), resulting from the loss of the extra trisomic chromosome in the embryonic stem cells, would be expected to occur in a proportion of pregnancies with CPM. We have studied 27 pregnancies with CPM involving trisomies for chromosomes 2, 7, 9, 10, 12, and 16 for involvement of specific cell lineage(s) and levels of mosaicism in term placentas. Also, DNA from the parents and infant was analyzed for UPD or biparental disomy (BPD). Five infants with UPD for chromosome 16 and one infant with UPD for chromosome 7 were detected. All other infants showed BPD for the chromosome involved in CPM. For trisomy 16 mosaic gestations, a close correlation between high levels of trisomic cells in placenta and intrauterine fetal growth restriction has been found irrespective of the type of disomy present in the infant. The effect of other trisomies (2, 7, 9, 10, 12) on placental function appears to be similar, but the low numbers of pregnancies studied and lack of detection of UPD for chromosomes 2, 9, 10 and 12 does not allow a definitive conclusion.
- OSTI ID:
- 133293
- Report Number(s):
- CONF-941009--
- Journal Information:
- American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
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