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Kypros H. Nicolaides - One of the best experts on this subject based on the ideXlab platform.

  • Trisomy 13 detection in the first trimester of pregnancy using a chromosome selective cell free dna analysis method
    Ultrasound in Obstetrics & Gynecology, 2013
    Co-Authors: Ghalia Ashoor, Craig A Struble, Ken Song, Arnold Oliphant, Eric Wang, Argyro Syngelaki, Kypros H. Nicolaides
    Abstract:

    Objective To assess the performance of chromosome-selective sequencing of maternal plasma cell-free DNA (cfDNA) in non-invasive prenatal testing for Trisomy 13. Methods Two-phase case–control study on a single plasma sample per case. The first phase was used to optimize the Trisomy 13 algorithm, which was then applied to a second dataset to determine the risk score for Trisomy 13 by laboratory personnel who were blinded to the fetal karyotype. Results In the first phase, Trisomy 13 risk scores were given for 11 cases of Trisomy 13 and 145 euploid cases at 11–13 weeks' gestation. The test identified seven (63.6%) cases of Trisomy 13 with no false positives. The Trisomy 13 algorithm was subsequently modified and the Trisomy 13 risk score was > 99% in all 11 cases of Trisomy 13 and 99% in eight (80.0% (95% confidence interval (CI), 49.0–94.3%)) cases of Trisomy 13. In the 1939 euploid cases the risk score for Trisomy 13 was 99% in one. Therefore, at the predefined risk cut-off of 1% for classifying a sample as high or low risk, the false-positive rate (FPR) was 0.05% (95% CI, 0.0–0.3%). Conclusions Chromosome-selective sequencing of cfDNA can detect the majority of cases of Trisomy 13 at an FPR of less than 0.1%.

  • Dilated Fourth Ventricle in Fetuses with Trisomy 18, Trisomy 13 and Triploidy at 11–13 Weeks’ Gestation
    Fetal diagnosis and therapy, 2012
    Co-Authors: Teresa Loureiro, Ana Fatima A. Ferreira, F. Ushakov, Nuno Montenegro, Kypros H. Nicolaides
    Abstract:

    Objective: To determine if in fetuses with aneuploidies the diameter of the fourth cerebral ventricle at 11–13 weeks’ gestation is different from euploid fetuses. Methods: The fourth ventricle at 11–13 weeks’ gestation was assessed in 62 cases of Trisomy 21, 32 of Trisomy 18, 10 of Trisomy 13, and 12 of triploidy and compared to 410 normal euploid fetuses. Transvaginal sonography was carried out and 3D brain volumes were acquired. The fetal head was assessed in an axial plane and the diameter of the fourth ventricle was measured. Values in aneuploid and euploid fetuses were compared. Results: The diameter of the fourth ventricle in Trisomy 18, Trisomy 13 and triploidy, but not in Trisomy 21, was significantly higher than in euploid fetuses. In the euploid fetuses the median diameter of the fourth ventricle was 1.9 mm and the 95th percentile was 2.5 mm. The measurements were above the median and the 95th percentile in 25 (78.1%) and 17 (53.1%) cases of Trisomy 18, in 10 (100%) and 8 (80.0%) of Trisomy 13, and in 10 (83.3%) and 10 (83.3%) of triploidy. Conclusions: In Trisomy 18, Trisomy 13 and triploidy the diameter of the fourth ventricle at 11–13 weeks’ gestation is increased.

  • Posterior brain in fetuses with Trisomy 18, Trisomy 13 and triploidy at 11 to 13 weeks' gestation
    Prenatal diagnosis, 2012
    Co-Authors: Ana Fatima A. Ferreira, Argyro Syngelaki, Anna Smolin, Ana-maria Vayna, Kypros H. Nicolaides
    Abstract:

    Objective To measure changes in the posterior fossa of first-trimester fetuses with Trisomy 18, Trisomy 13 and triploidy. Methods Brain stem (BS) diameter and BS to occipital bone (BSOB) diameter were measured in images of the midsagittal view of the face at 11+0 to 13+6 weeks from 45 Trisomy 18, 21 Trisomy 13 and 15 triploid fetuses and compared with values in 162 euploid fetuses. Results In euploid fetuses BS and BSOB diameters increased significantly with crown–rum length and the BS to BSOB ratio decreased. In all three aneuploidies BSOB diameter was significantly higher than in euploid fetuses. In Trisomy 18 and Trisomy 13, the BS diameter and BS to BSOB ratio were decreased. The BS to BSOB ratio was below the 5th percentile in 16 (35.6%), 17 (81.0%) and 5 (33.3%) of Trisomy 18, Trisomy 13 and triploidy, respectively. In 7 (8.6%) of the aneuploid fetuses there was open spina bifida and in all these cases the BS to BSOB ratio was above the 95th percentile. Conclusions At 11 to 13 weeks' gestation many fetuses with Trisomy 18, Trisomy 13 and triploidy have measurable abnormalities in the posterior brain. © 2012 John Wiley & Sons, Ltd.

  • chromosome selective sequencing of maternal plasma cell free dna for first trimester detection of Trisomy 21 and Trisomy 18
    American Journal of Obstetrics and Gynecology, 2012
    Co-Authors: Ghalia Ashoor, Argyro Syngelaki, Kypros H. Nicolaides, Marion Wagner, Cahit Birdir
    Abstract:

    OBJECTIVE: The purpose of this study was to assess the prenatal detection rate of Trisomy 21 and 18 and the false-positive rate by chromosome-selective sequencing of maternal plasma cell–free DNA. STUDY DESIGN: Nested case-control study of cell-free DNA was examined in plasma that was obtained at 11-13 weeks before chorionic villous sampling from 300 euploid pregnancies, 50 pregnancies with Trisomy 21, and 50 pregnancies with Trisomy 18. Laboratory personnel were blinded to fetal karyotype. RESULTS: Risk scores for Trisomy 21 and 18 were given for 397 of the 400 samples that were analyzed. In all 50 cases of Trisomy 21, the risk score for Trisomy 21 was99%, and the risk score for Trisomy 18 was 0.01%. In all 50 cases of Trisomy 18, the risk score for Trisomy 21 was 0.01%, and the risk score for Trisomy 18 was 99% in 47 cases, 98.8% in 1 case, 88.5% in 1 case, and 0.11% in 1 case. In 3 of the 300 euploid pregnancies (1%), no risk score was provided, because there was failed amplification and sequencing. In the remaining 297 cases, the risk score for Trisomy 21 was0.01%, and the risk score for Trisomy 18 was0.01% in 295 cases, 0.04% in 1 case, and 0.23% in 1 case. Therefore, the sensitivity for detecting Trisomy 21 was 100% (50/50 cases); the sensitivity for Trisomy 18 was 98% (49/50 cases), and the specificity was 100% (297/297 cases). CONCLUSION: In this study, chromosome-selective sequencing of cellfree DNA separated all cases of Trisomy 21 and 98% of Trisomy 18 from euploid pregnancies.

  • Chromosome-selective sequencing of maternal plasma cell–free DNA for first-trimester detection of Trisomy 21 and Trisomy 18
    American journal of obstetrics and gynecology, 2012
    Co-Authors: Ghalia Ashoor, Argyro Syngelaki, Marion Wagner, Cahit Birdir, Kypros H. Nicolaides
    Abstract:

    OBJECTIVE: The purpose of this study was to assess the prenatal detection rate of Trisomy 21 and 18 and the false-positive rate by chromosome-selective sequencing of maternal plasma cell–free DNA. STUDY DESIGN: Nested case-control study of cell-free DNA was examined in plasma that was obtained at 11-13 weeks before chorionic villous sampling from 300 euploid pregnancies, 50 pregnancies with Trisomy 21, and 50 pregnancies with Trisomy 18. Laboratory personnel were blinded to fetal karyotype. RESULTS: Risk scores for Trisomy 21 and 18 were given for 397 of the 400 samples that were analyzed. In all 50 cases of Trisomy 21, the risk score for Trisomy 21 was99%, and the risk score for Trisomy 18 was 0.01%. In all 50 cases of Trisomy 18, the risk score for Trisomy 21 was 0.01%, and the risk score for Trisomy 18 was 99% in 47 cases, 98.8% in 1 case, 88.5% in 1 case, and 0.11% in 1 case. In 3 of the 300 euploid pregnancies (1%), no risk score was provided, because there was failed amplification and sequencing. In the remaining 297 cases, the risk score for Trisomy 21 was0.01%, and the risk score for Trisomy 18 was0.01% in 295 cases, 0.04% in 1 case, and 0.23% in 1 case. Therefore, the sensitivity for detecting Trisomy 21 was 100% (50/50 cases); the sensitivity for Trisomy 18 was 98% (49/50 cases), and the specificity was 100% (297/297 cases). CONCLUSION: In this study, chromosome-selective sequencing of cellfree DNA separated all cases of Trisomy 21 and 98% of Trisomy 18 from euploid pregnancies.

Argyro Syngelaki - One of the best experts on this subject based on the ideXlab platform.

  • Trisomy 13 detection in the first trimester of pregnancy using a chromosome selective cell free dna analysis method
    Ultrasound in Obstetrics & Gynecology, 2013
    Co-Authors: Ghalia Ashoor, Craig A Struble, Ken Song, Arnold Oliphant, Eric Wang, Argyro Syngelaki, Kypros H. Nicolaides
    Abstract:

    Objective To assess the performance of chromosome-selective sequencing of maternal plasma cell-free DNA (cfDNA) in non-invasive prenatal testing for Trisomy 13. Methods Two-phase case–control study on a single plasma sample per case. The first phase was used to optimize the Trisomy 13 algorithm, which was then applied to a second dataset to determine the risk score for Trisomy 13 by laboratory personnel who were blinded to the fetal karyotype. Results In the first phase, Trisomy 13 risk scores were given for 11 cases of Trisomy 13 and 145 euploid cases at 11–13 weeks' gestation. The test identified seven (63.6%) cases of Trisomy 13 with no false positives. The Trisomy 13 algorithm was subsequently modified and the Trisomy 13 risk score was > 99% in all 11 cases of Trisomy 13 and 99% in eight (80.0% (95% confidence interval (CI), 49.0–94.3%)) cases of Trisomy 13. In the 1939 euploid cases the risk score for Trisomy 13 was 99% in one. Therefore, at the predefined risk cut-off of 1% for classifying a sample as high or low risk, the false-positive rate (FPR) was 0.05% (95% CI, 0.0–0.3%). Conclusions Chromosome-selective sequencing of cfDNA can detect the majority of cases of Trisomy 13 at an FPR of less than 0.1%.

  • Posterior brain in fetuses with Trisomy 18, Trisomy 13 and triploidy at 11 to 13 weeks' gestation
    Prenatal diagnosis, 2012
    Co-Authors: Ana Fatima A. Ferreira, Argyro Syngelaki, Anna Smolin, Ana-maria Vayna, Kypros H. Nicolaides
    Abstract:

    Objective To measure changes in the posterior fossa of first-trimester fetuses with Trisomy 18, Trisomy 13 and triploidy. Methods Brain stem (BS) diameter and BS to occipital bone (BSOB) diameter were measured in images of the midsagittal view of the face at 11+0 to 13+6 weeks from 45 Trisomy 18, 21 Trisomy 13 and 15 triploid fetuses and compared with values in 162 euploid fetuses. Results In euploid fetuses BS and BSOB diameters increased significantly with crown–rum length and the BS to BSOB ratio decreased. In all three aneuploidies BSOB diameter was significantly higher than in euploid fetuses. In Trisomy 18 and Trisomy 13, the BS diameter and BS to BSOB ratio were decreased. The BS to BSOB ratio was below the 5th percentile in 16 (35.6%), 17 (81.0%) and 5 (33.3%) of Trisomy 18, Trisomy 13 and triploidy, respectively. In 7 (8.6%) of the aneuploid fetuses there was open spina bifida and in all these cases the BS to BSOB ratio was above the 95th percentile. Conclusions At 11 to 13 weeks' gestation many fetuses with Trisomy 18, Trisomy 13 and triploidy have measurable abnormalities in the posterior brain. © 2012 John Wiley & Sons, Ltd.

  • chromosome selective sequencing of maternal plasma cell free dna for first trimester detection of Trisomy 21 and Trisomy 18
    American Journal of Obstetrics and Gynecology, 2012
    Co-Authors: Ghalia Ashoor, Argyro Syngelaki, Kypros H. Nicolaides, Marion Wagner, Cahit Birdir
    Abstract:

    OBJECTIVE: The purpose of this study was to assess the prenatal detection rate of Trisomy 21 and 18 and the false-positive rate by chromosome-selective sequencing of maternal plasma cell–free DNA. STUDY DESIGN: Nested case-control study of cell-free DNA was examined in plasma that was obtained at 11-13 weeks before chorionic villous sampling from 300 euploid pregnancies, 50 pregnancies with Trisomy 21, and 50 pregnancies with Trisomy 18. Laboratory personnel were blinded to fetal karyotype. RESULTS: Risk scores for Trisomy 21 and 18 were given for 397 of the 400 samples that were analyzed. In all 50 cases of Trisomy 21, the risk score for Trisomy 21 was99%, and the risk score for Trisomy 18 was 0.01%. In all 50 cases of Trisomy 18, the risk score for Trisomy 21 was 0.01%, and the risk score for Trisomy 18 was 99% in 47 cases, 98.8% in 1 case, 88.5% in 1 case, and 0.11% in 1 case. In 3 of the 300 euploid pregnancies (1%), no risk score was provided, because there was failed amplification and sequencing. In the remaining 297 cases, the risk score for Trisomy 21 was0.01%, and the risk score for Trisomy 18 was0.01% in 295 cases, 0.04% in 1 case, and 0.23% in 1 case. Therefore, the sensitivity for detecting Trisomy 21 was 100% (50/50 cases); the sensitivity for Trisomy 18 was 98% (49/50 cases), and the specificity was 100% (297/297 cases). CONCLUSION: In this study, chromosome-selective sequencing of cellfree DNA separated all cases of Trisomy 21 and 98% of Trisomy 18 from euploid pregnancies.

  • Chromosome-selective sequencing of maternal plasma cell–free DNA for first-trimester detection of Trisomy 21 and Trisomy 18
    American journal of obstetrics and gynecology, 2012
    Co-Authors: Ghalia Ashoor, Argyro Syngelaki, Marion Wagner, Cahit Birdir, Kypros H. Nicolaides
    Abstract:

    OBJECTIVE: The purpose of this study was to assess the prenatal detection rate of Trisomy 21 and 18 and the false-positive rate by chromosome-selective sequencing of maternal plasma cell–free DNA. STUDY DESIGN: Nested case-control study of cell-free DNA was examined in plasma that was obtained at 11-13 weeks before chorionic villous sampling from 300 euploid pregnancies, 50 pregnancies with Trisomy 21, and 50 pregnancies with Trisomy 18. Laboratory personnel were blinded to fetal karyotype. RESULTS: Risk scores for Trisomy 21 and 18 were given for 397 of the 400 samples that were analyzed. In all 50 cases of Trisomy 21, the risk score for Trisomy 21 was99%, and the risk score for Trisomy 18 was 0.01%. In all 50 cases of Trisomy 18, the risk score for Trisomy 21 was 0.01%, and the risk score for Trisomy 18 was 99% in 47 cases, 98.8% in 1 case, 88.5% in 1 case, and 0.11% in 1 case. In 3 of the 300 euploid pregnancies (1%), no risk score was provided, because there was failed amplification and sequencing. In the remaining 297 cases, the risk score for Trisomy 21 was0.01%, and the risk score for Trisomy 18 was0.01% in 295 cases, 0.04% in 1 case, and 0.23% in 1 case. Therefore, the sensitivity for detecting Trisomy 21 was 100% (50/50 cases); the sensitivity for Trisomy 18 was 98% (49/50 cases), and the specificity was 100% (297/297 cases). CONCLUSION: In this study, chromosome-selective sequencing of cellfree DNA separated all cases of Trisomy 21 and 98% of Trisomy 18 from euploid pregnancies.

  • Maternal serum human placental growth hormone at 11 to 13 weeks in Trisomy 21 and Trisomy 18 pregnancies
    Prenatal diagnosis, 2010
    Co-Authors: Stavros Sifakis, Argyro Syngelaki, Ranjit Akolekar, Jader De Jesus Cruz, Kypros H. Nicolaides
    Abstract:

    Objective To investigate the maternal serum concentration of human placental growth hormone (hPGH) in Trisomy 21 and Trisomy 18 pregnancies at 11 to 13 weeks of gestation and to examine the possible association between fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotrophin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Methods The maternal serum concentration of hPGH at 11 to 13 weeks was measured in a case–control study from 28 pregnancies with fetal Trisomy 21, 28 with Trisomy 18 and 112 pregnancies with euploid fetuses. The median hPGH multiple of the median (MoM) in Trisomy 21 and Trisomy 18 pregnancies were compared with euploid pregnancies. Results Serum hPGH was significantly lower in Trisomy 21 (0.93 MoM) and Trisomy 18 (0.62 MoM) compared to euploid pregnancies (1.02 MoM). There was a significant association between serum hPGH and PAPP-A in both the euploid (r = 0.258, p = 0.006) and Trisomy 21 pregnancies (r = 0.410, p = 0.030) but not in Trisomy 18 pregnancies (p = 0.445). Conclusion In the first trimester, serum hPGH in Trisomy 21 and Trisomy 18 pregnancies is reduced. This is the opposite of findings in previous studies reporting that in the second trimester, Trisomy 21 and 18 pregnancies have increased hPGH. Copyright © 2010 John Wiley & Sons, Ltd.

Joan K Morris - One of the best experts on this subject based on the ideXlab platform.

  • Revised estimates of the risk of fetal loss following a prenatal diagnosis of Trisomy 13 or Trisomy 18
    American Journal of Medical Genetics Part A, 2017
    Co-Authors: Alana Cavadino, Joan K Morris
    Abstract:

    Edwards syndrome (Trisomy 18) and Patau syndrome (Trisomy 13) both have high natural fetal loss rates. The aim of this study was to provide estimates of these fetal loss rates by single gestational week of age using data from the National Down Syndrome Cytogenetic Register. Data from all pregnancies with Edwards or Patau syndrome that were prenatally detected in England and Wales from 2004 to 2014 was analyzed using Kaplan-Meier survival estimates. Pregnancies were entered into the analysis at the time of gestation at diagnosis, and were considered "under observation" until the gestation at outcome. There were 4088 prenatal diagnoses of Trisomy 18 and 1471 of Trisomy 13 in the analysis. For Trisomy 18, 30% (95%CI: 25-34%) of viable fetuses at 12 weeks will result in a live birth and at 39 weeks gestation 67% (60-73%) will result in a live birth. For Trisomy 13 the survival is 50% (41-58%) at 12 weeks and 84% (73-90%) at 39 weeks. There was no significant difference in survival between males and females when diagnosed at 12 weeks for Trisomy 18 (P-value = 0.27) or Trisomy 13 (P-value = 0.47). This paper provides the most precise gestational age-specific estimates currently available for the risk of fetal loss in Trisomy 13 and Trisomy 18 pregnancies in a general population.

  • Survival of Trisomy 18 (Edwards syndrome) and Trisomy 13 (Patau Syndrome) in England and Wales: 2004-2011.
    American journal of medical genetics. Part A, 2013
    Co-Authors: Anna Springett, Joan K Morris
    Abstract:

    The aim of this study is to determine the survival of live births with Trisomy 18 and Trisomy 13 and their variants. Information on live births with Trisomy 18 or Trisomy 13 recorded in the National Down Syndrome Cytogenetic Register (NDSCR) was linked by the NHS Information Centre to obtain information about survival. Survival was known for 326 (88%) of live births with Trisomy 18 and 142 (82%) of live births with Trisomy 13 born in England and Wales between 2004 and 2011. The median survival time for live births with full Trisomy 18 was 14 days and with full Trisomy 13 was 10 days, the 3-month survival was 20% and 18%, respectively, and the 1-year survival for both syndromes was 8%. The 1-year survival for live births with Trisomy 18 mosaicism (n = 17) was 70%, for those with Trisomy 13 mosaicism (n = 5) was 80% and for those with partial Trisomy 13 (Robertsonian translocations) (n = 17) was 29%. This study is based on the largest data set on survival for live births with Trisomy 18 and Trisomy 13. Although median survival for these children is 2 weeks or less, about one in five survive for 3 months or more and about 1 in 12 survive for 1 year or more. We suggest that these survival rates are used in counselling as well as the median survival time.

  • Trisomy 21 mosaicism and maternal age.
    American journal of medical genetics. Part A, 2012
    Co-Authors: Joan K Morris
    Abstract:

    The aim of this study was to quantify the maternal age-specific risk for Trisomy 21 mosaicism. Data were obtained on 322 Trisomy 21 diagnoses with mosaicism and 27,943 simple Trisomy 21 diagnoses recorded in the National Down Syndrome Cytogenetic Register from 1989 to 2009 in England and Wales. Trisomy 21 cases with mosaicism have a mean maternal age of 33.1 years compared to 35.0 years for free Trisomy 21 cases. Sixty-seven percent of Trisomy 21 diagnoses with mosaicism are maternal age dependent, with a risk 0.8% that of the corresponding maternal age specific risk for simple Trisomy 21. However 33% (0.8 per 100,000 births) are not maternal age dependent, indicating that maternal age is not the only risk factor for mosaicism. Trisomy 21 diagnoses with mosaicism are more likely to be female than free Trisomy 21 diagnoses, however there was no association of fetal sex with maternal age which indicates that there is another factor involved in the presence of mosaicism not associated with maternal age, but associated with fetal sex.

  • the maternal age specific live birth prevalence of trisomies 13 and 18 compared to Trisomy 21 down syndrome
    Prenatal Diagnosis, 2009
    Co-Authors: George M Savva, Kate Walker, Joan K Morris
    Abstract:

    To estimate the maternal age-specific live birth prevalence (in the absence of prenatal diagnosis and selective termination) of Trisomy 13 (Patau syndrome) and Trisomy 18 (Edwards syndrome) and compare it with that of Trisomy 21 (Down syndrome).

K H Nicolaides - One of the best experts on this subject based on the ideXlab platform.

  • routine first trimester screening for fetal trisomies in twin pregnancy cell free dna test contingent on results from combined test
    Ultrasound in Obstetrics & Gynecology, 2019
    Co-Authors: S Galeva, Ranjit Akolekar, L Konstantinidou, M M Gil, K H Nicolaides
    Abstract:

    Objective To report on the routine clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13, contingent on the results of the first-trimester combined test in twin pregnancy. Methods Screening for trisomies 21, 18 and 13 was carried out in 959 twin pregnancies by assessment of a combination of maternal age, fetal nuchal translucency thickness, and serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein-A at 11-13 weeks' gestation in two UK NHS hospitals. Women in the high-risk group (risk ≥ 1 in 100) were offered the option of invasive testing, cfDNA testing or no further testing, and those in the intermediate-risk group (risk 1 in 101 to 1 in 2500 in the first phase of the study and 1 in 101 to 1 in 500 in the second phase) were offered cfDNA or no further testing. The trisomic status of the pregnancies was determined by prenatal or postnatal karyotyping or examination of the neonates. Results In 42 (4.4%) of the 959 pregnancies, there was termination, miscarriage or stillbirth with no known karyotype or there was loss to follow-up. The 917 pregnancies with known trisomic status of both twins included six that were discordant for Trisomy 21, four that were discordant for Trisomy 18 and 907 with no Trisomy 21, 18 or 13. Following combined screening, 47 (5.1%), 203 (22.1%) and 667 (72.7%) of the pregnancies were classified as high risk, intermediate risk and low risk, respectively. The high-risk group included five (83.3%) cases of Trisomy 21 and three (75.0%) of Trisomy 18. The cfDNA test was carried out in 224 pregnancies and results were provided in 214 (95.5%); this group included six pregnancies with Trisomy 21, three with Trisomy 18 and 206 with no Trisomy 21, 18 or 13. The cfDNA test classified correctly as screen positive all six cases of Trisomy 21 and two of the three with Trisomy 18, and as screen negative for each of the trisomies all 206 unaffected pregnancies. Contingent screening led to prenatal detection of all cases of Trisomy 21 and three of four with Trisomy 18. Conclusion This study has demonstrated the feasibility of introducing cfDNA testing, contingent on the results of the first-trimester combined test for major trisomies, in a routine population of twin pregnancies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

  • clinical performance of non invasive prenatal testing nipt using targeted cell free dna analysis in maternal plasma with microarrays or next generation sequencing ngs is consistent across multiple controlled clinical studies
    Prenatal Diagnosis, 2015
    Co-Authors: Renee Stokowski, Eric Wang, Karen White, Annette Batey, Bo Jacobsson, Herb Brar, Madhumitha Balanarasimha, Desiree Hollemon, Andrew B Sparks, K H Nicolaides
    Abstract:

    Objective To evaluate the clinical performance of non-invasive prenatal testing for Trisomy 21, 18, and 13 using targeted cell-free DNA (cfDNA) analysis. Methods Targeted cfDNA analysis using DANSR™ and FORTE™ with microarray quantitation was used to evaluate the risk of Trisomy 21, 18, and 13 in blinded samples from 799 singleton, twin, natural, and IVF pregnancies. Subjects either had fetal chromosome evaluation by karyotype, FISH, QF-PCR, or karyotype for newborns with suspected aneuploidy at birth. The results of targeted cfDNA analysis were compared to clinical genetic testing outcomes to assess clinical performance. Results Targeted cfDNA analysis with microarray quantification identified 107/108 Trisomy 21 cases (99.1%), 29/30 Trisomy 18 cases (96.7%), and 12/12 Trisomy 13 cases (100%). The specificity was 100% for all three trisomies. Combining this data with all published clinical performance studies using DANSR/FORTE methodology for greater than 23 000 pregnancies, the sensitivity of targeted cfDNA analysis was calculated to be greater than 99% for Trisomy 21, 97% for Trisomy 18, and 94% for Trisomy 13. Specificity for each Trisomy was greater than 99.9%. Conclusion Targeted cfDNA analysis demonstrates consistently high sensitivity and extremely low false positive rates for common autosomal trisomies in pregnancy across quantitation platforms. © 2015 Ariosa Diagnostics Inc. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

  • screening for Trisomy 21 by maternal age fetal nuchal translucency thickness free beta human chorionic gonadotropin and pregnancy associated plasma protein a
    Ultrasound in Obstetrics & Gynecology, 2008
    Co-Authors: K O Kagan, David Wright, A Baker, Daljit Singh Sahota, K H Nicolaides
    Abstract:

    Objectives To derive a model and examine the performance of first-trimester screening for Trisomy 18 by maternal age, fetal nuchal translucency (NT) thickness, and maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Methods Prospective combined screening for Trisomy 21 was performed at 11 + 0t o 13+ 6 weeks in 56 893 singleton pregnancies, including 56 376 cases of euploid fetuses, 395 with Trisomy 21 and 122 with Trisomy 18. The measured free β-hCG and PAPP-A were converted into a multiple of the median (MoM) and then into likelihood ratios (LR). Similarly, the measured NT was transformed into LRs using the mixture model of NT distributions. In each case the LRs for NT and the biochemical markers were multiplied by the age and gestation-related risk to derive the risk for Trisomy 21 and Trisomy 18. Detection rates (DRs) and false-positive rates (FPRs) were calculated by taking the proportions with risks above a given risk threshold. Results In screening with the algorithm for Trisomy 21, at a FPR of 3%, the estimated DRs of trisomies 21 and 18 were 89% and 82%, respectively. The use of an algorithm for Trisomy 18 identified 93% of affected fetuses at a FPR of 0.2%. When the algorithm for Trisomy 21 was used and screen positivity was fixed at a FPR of 3%, and in addition the algorithm for Trisomy 18 was used and screen positivity was fixed at a FPR of 0.2%, the overall FPR was 3.1% and the DRs of trisomies 21 and 18 were 90% and 97%, respectively. Conclusions A beneficial side effect of first-trimester combined screening for Trisomy 21 is the detection of a

J. De Grouchy - One of the best experts on this subject based on the ideXlab platform.

  • Trisomy 18q‐. Trisomy mapping of chromosome 18 revisited
    Clinical genetics, 2008
    Co-Authors: Catherine Turleau, Françoise Chavin-colin, R. Narbouton, D. Asensi, J. De Grouchy
    Abstract:

    Two patients with Trisomy for 18p and the proximal segment of 18q (Trisomy 18q –) are reported and compared with similar cases from the literature. The phenotype of Trisomy 18q– resembles that of full Trisomy 18 but differs mainly in the birdlike face, small mouth, more pronounced microretrognathia, minor skeletal dysplasia and inner organ malformations, and less severe vital prognosis.

  • Trisomy 18qter and Trisomy mapping of chromosome 18.
    Clinical genetics, 2008
    Co-Authors: Catherine Turleau, J. De Grouchy
    Abstract:

    Four cases of partial Trisomy 18q are reported and compared to observations from the literature. The phenotype of 18qter Trisomy is described and compared to full Trisomy 18.