Request PDF | Monochorionic-diamniotic twins discordant in gender from a naturally conceived pregnancy through postzygotic sex chromosome loss in a 47,XXY ...ArticleMonochorionic-diamniotictwinsdiscordantingenderfromanaturallyconceivedpregnancythroughpostzygoticsexchromosomelossina47,XXYzygoteAugust2008PrenatalDiagnosis28(8):759-63DOI:10.1002/pd.2031SourcePubMedAuthors:NicolasHZechJosefWisserUniversityofZurichGiancarloNatalucciUniversityofZurichMariluceRiegelHospitaldeClínicasdePortoAlegreShowall6authorsHideRequestfull-textPDFToreadthefull-textofthisresearch,youcanrequestacopydirectlyfromtheauthors.Requestfull-textDownloadcitationCopylinkLinkcopiedRequestfull-textDownloadcitationCopylinkLinkcopiedToreadthefull-textofthisresearch,youcanrequestacopydirectlyfromtheauthors.Citations(34)References(13)AbstractItisgenerallybelievedthatmonochorionic-diamniotictwinpregnanciesresultfromonefertilizedoocytewithbothsiblingshavingthesamegenotypeandphenotype.Inrareinstances,duetosomaticmutationsorchromosomeaberrations,thekaryotypesandphenotypesofthetwotwinscandiffer.Wereportcytogenetic,moleculargeneticandclinicalexaminationsinmonochorionic-diamniotictwinsdiscordantingender.Themonochorionic-diamnioticstatusofthetwinswasdiagnosedbyultrasoundandhistologicexaminationoftheplacenta.Prenatalchromosomeexaminationperformedonamniocytesrevealedanormalfemalekaryotypeinoneanda46,XX(26)/46,XY(3)karyotypeintheothertwin.Molecularexaminationsconfirmedmonozygositydespitediscordantsex.Basedonthecytogeneticandmolecularresultsoflymphocytesandplacentalcells,theonlyexplanationforgenderdiscordancewasthattheconceptusoriginallyhada47,XXYchromosomecomplement.A47,XXYzygoteappearstohaveundergoneatwinningprocess.ApostzygoticlossoftheXchromosomeinsomecellsandtheYchromosomeinothercells,eitherbeforeoraftertwinning,resultedin46,XX/46,XYmosaicisminbothmonozygotic(MZ)twins.ThesexdiscordanceoftheMZtwinscanbeexplainedbydifferentproportionsofthe46,XXand46,XYcelllinesinthegonadsandothertissues.Discovertheworld'sresearch