Triple paternal contribution to a normal/complete molar chimeric singleton placenta.
A comprehensive study of unusual cases of placental pathology may provide insight into mechanisms of normal human fertilization and early embryonic development by examining the exception to the rule. A gravida three para two 39-year-old woman was monitored by ultrasound from 16 weeks of gestation for cystic placenta. A female newborn was born at 36 weeks gestation. Pathologic examination of the partially cystic placenta revealed a singleton placenta comprised of 2/3 normal placenta and 1/3 complete hydatidiform mole, largely degenerated. Immunostaining for p57 was negative in stromal cells of the molar villi. Chromogenic in-situ hybridization revealed diploidy in both normal and molar parts. A total of 16 microsatellites were studied by short tandem repeat analysis, 11 of which were informative. The analysis revealed bipaternal molar tissue of dispermic origin. The paternal monospermic contribution to the normal part was different from that in the molar part, thus resulting in tripaternal contribution to the conceptus. A chimera is a single organism composed of two or more different populations of genetically distinct cells that originated from different zygotes (tetragametic) whereas mosaic is a mixture of two cell lines in one organism originating from one zygote. The possible mechanisms leading to the formation of chimeric/mosaic placenta in our case (one of the components being complete hydatidiform mole), including twinning, fusion at an early embryonic stage and diploidization of triploids, are discussed.
The Perinatal Pathology Unit, Department of Pathology, Hadassah-Hebrew University Medical Center, Mount Scopus, PO Box 24035, Jerusalem il-91240, Israel.
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Ariel
The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem, Israel.
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Goldman-Wohl
The Magda and Richard Hoffman Center for Human Placenta Research, Department of Obstetrics and Gynecology, Hadassah-Hebrew University Medical Center, Mount Scopus, Jerusalem, Israel.
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Yagel
The Laboratory for Tissue typing, Chaim Sheba Medical Center, Tel Hashomer, Israel.
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Gazit
The Laboratory for Tissue typing, Chaim Sheba Medical Center, Tel Hashomer, Israel.
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Loewenthal
D000328:Adult; D002678:Chimera / Q000235:genetics*; D005260:Female; D006801:Humans; D006828:Hydatidiform Mole / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology; D007231:Infant, Newborn; D009030:Mosaicism; D010920:Placenta / Q000000981:diagnostic imaging / Q000473:pathology*; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology
chimera; complete hydatidiform mole; diploidization of triploids; mosaic; polyspermy