{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T13:31:19Z","timestamp":1791207079075,"version":"4.1.0"},"reference-count":28,"publisher":"Oxford University Press (OUP)","issue":"1","license":[{"start":{"date-parts":[[2010,1,1]],"date-time":"2010-01-01T00:00:00Z","timestamp":1262304000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/501100001839","name":"University Grants Committee","doi-asserted-by":"publisher","award":["AoE\/M-04\/06"],"award-info":[{"award-number":["AoE\/M-04\/06"]}],"id":[{"id":"10.13039\/501100001839","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2010,1,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Background: Maternal plasma mRNA encoded by the PLAC4 gene (placenta-specific 4), which is transcribed from chromosome 21 in placental cells, is a potential marker for the noninvasive assessment of chromosome 21 dosage in the fetus. We evaluated the diagnostic sensitivities and specificities of 2 trisomy 21\u2013screening approaches that use maternal plasma PLAC4 mRNA.<\/jats:p>\n               <jats:p>Methods: We studied maternal plasma samples from 153 pregnant women carrying euploid and trisomy 21 fetuses. For the samples in which the fetuses were heterozygous for the studied PLAC4 single-nucleotide polymorphism (SNP), we measured the ratio between 2 alleles of the SNP in maternal plasma PLAC4 mRNA (RNA-SNP) by mass spectrometric (MS) and digital PCR methods. For pregnancies involving fetuses homozygous for the SNP, we quantified the total PLAC4 mRNA concentration in maternal plasma by real-time PCR and digital PCR.<\/jats:p>\n               <jats:p>Results: For the RNA-SNP approach, we achieved a diagnostic sensitivity and specificity of 100% (95% CI, 40.2%\u2013100%) and 89.7% (95% CI, 78.8%\u201396.1%), respectively, for both the MS and the digital PCR methods. For the mRNA-quantification approach, the areas under the ROC curves were 0.859 (95% CI, 0.741\u20130.903) and 0.833 (95% CI, 0.770\u20130.923) for plasma PLAC4 mRNA concentrations measured by the real-time PCR and the digital PCR methods, respectively.<\/jats:p>\n               <jats:p>Conclusions: For prenatal screening of trisomy 21, the quantification of the total PLAC4 mRNA concentration can be used in a synergistic manner with the RNA-SNP allelic ratio approach to increase the population coverage of cases in which diagnostic information can be obtained.<\/jats:p>","DOI":"10.1373\/clinchem.2009.132662","type":"journal-article","created":{"date-parts":[[2009,11,5]],"date-time":"2009-11-05T21:54:41Z","timestamp":1257458081000},"page":"73-81","source":"Crossref","is-referenced-by-count":47,"title":["Synergy of Total PLAC4 RNA Concentration and Measurement of the RNA Single-Nucleotide Polymorphism Allelic Ratio for the Noninvasive Prenatal Detection of Trisomy 21"],"prefix":"10.1093","volume":"56","author":[{"given":"Nancy BY","family":"Tsui","sequence":"first","affiliation":[{"name":"Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, and the Departments of"},{"name":"Chemical Pathology and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ranjit","family":"Akolekar","sequence":"first","affiliation":[{"name":"Harris Birthright Research Centre for Fetal Medicine, King\u2019s College Hospital, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rossa WK","family":"Chiu","sequence":"first","affiliation":[{"name":"Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, and the Departments of"},{"name":"Chemical Pathology and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katherine CK","family":"Chow","sequence":"first","affiliation":[{"name":"Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, and the Departments of"},{"name":"Chemical Pathology and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tak Y","family":"Leung","sequence":"first","affiliation":[{"name":"Obstetrics and Gynecology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tze K","family":"Lau","sequence":"first","affiliation":[{"name":"Obstetrics and Gynecology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kypros H","family":"Nicolaides","sequence":"first","affiliation":[{"name":"Harris Birthright Research Centre for Fetal Medicine, King\u2019s College Hospital, London, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"YM Dennis","family":"Lo","sequence":"first","affiliation":[{"name":"Centre for Research into Circulating Fetal 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