1/4. Complete hydatidiform mole retaining a chromosome 11 of maternal origin: molecular genetic analysis of a case.Hydatidiform moles are pregnancies characterized by abnormal development of both embryonic and extraembryonic tissues and are associated with the misexpression of imprinted genes. The vast majority of complete hydatidiform moles are diploid and androgenetic, whereas partial hydatidiform moles are triploid, with an extra set of chromosomes of paternal origin. Here, we present an unusual complete mole that showed strong expression of two imprinted, maternally transcribed genes, CDKN1C (encoding p57(KIP2)) and PHLDA2 (TSSC3/IPL), both part of a large imprinted gene domain on chromosome 11. Using microsatellite genotyping and fluorescent in situ hybridization, we show that this paradoxical gene expression was due to retention of a maternal copy of chromosome 11 in addition to the two paternal copies normally present in complete moles. These findings demonstrate that, despite being predominantly androgenetic, some complete moles contain small amounts of dna of maternal origin. Furthermore, these results provide an explanation for rare false negatives that can arise when p57(KIP2) is used as a diagnostic marker for complete moles.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/4. Persistent gestational trophoblastic disease after an androgenetic/biparental fetal chimera: a case report and review.We present a case of a dichorionic/diamniotic twin pregnancy in which one twin presented with ultrasound findings suggestive of molar changes in the placenta. The placenta of twin A seemed to be grossly enlarged and cystic, and twin A was small for gestation. After an inevitable abortion, a detailed histological and genetic evaluation was performed on the fetus and placenta from twin A, including traditional cytogenetic techniques, microsatellite marker analysis, fluorescent in situ hybridization, and p57 immunostaining. It was determined that twin A was a chimera with a biparental XX cell line and an androgenetic XY cell line. The 2 cell lines were present in both the placenta and the fetus. The patient later developed and was treated for persistent gestational trophoblastic disease, which has been shown to have an increased risk after an androgenetic conception. Cases of mosaicism or chimerism involving an androgenetic cell line may be difficult to diagnose histologically but are critical to identify because of the increased risk for persistent gestational trophoblastic disease. Therefore, we emphasize the importance of using multiple molecular, cytogenetic, and immunohistochemical techniques when diagnosing cases involving such unusual placental abnormalities. To our knowledge, this is the first reported case of persistent gestational disease after a fetal chimera.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/4. Triploid partial molar pregnancy detected through maternal serum alpha-fetoprotein and HCG screening.BACKGROUND: Screening for down syndrome using maternal serum alpha-fetoprotein (MSAFP) and hCG, with or without unconjugated estriol (E3), has become standard practice in much of the united states. When both MSAFP and hCG are elevated, the possibility of a partial molar pregnancy with fetal neural tube or abdominal-wall defect should be added to the differential diagnosis, as illustrated by this case. CASE: A 22-year-old woman had elevated MSAFP and hCG levels on routine screening at 16 weeks' gestation. Ultrasound examination suggested a neural tube defect and a thickened placenta. amniocentesis was performed. She very rapidly developed preeclampsia. fluorescence in situ hybridization showed three distinct spots for the three probes tested. A triploid karyotype was confirmed with standard cytogenetic analysis. The fetus had an open neural tube defect, and placental pathology was consistent with a partial hydatidiform mole. CONCLUSIONS: A possible partial molar pregnancy with abdominal-wall or open neural tube defect should be added to the differential diagnosis for interpreting down syndrome screens when both MSAFP and hCG are elevated. A presumptive diagnosis of triploidy using fluorescence in situ hybridization was important in the management of this pregnancy.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
4/4. Intracytoplasmic sperm injection combined with preimplantation genetic diagnosis for the prevention of recurrent gestational trophoblastic disease.A strategy for the prevention of repeated molar pregnancies by using intracytoplasmic sperm injection (ICSI) coupled with preimplantation genetic diagnosis (PGD) with fluorescence in-situ hybridization (FISH) was developed. In this approach, complete moles which arise from dispermic fertilization are avoided by the use of ICSI. ICSI is followed by preimplantation selection against the transfer of 46,XX embryos, thus preventing complete moles resulting from a fertilization of an inactive oocyte, by a haploid X-bearing spermatozoon which subsequently duplicates. Triploid partial moles which arise mainly from dispermic fertilization may also be prevented by ICSI. The preimplantation confirmation of diploidy by FISH guards against triploid partial moles which may result from mechanisms other than dispermic fertilization. The employment of this strategy in an attempt to prevent a repeated event of molar pregnancy in a patient with a history of two previous episodes of gestational trophoblastic disease is reported.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |