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Objective: To analyze the results of prenatal diagnosis and outcome of pregnancy for women with a high risk for fetal aneuploidies., Methods: A total of 747 cases of prenatal diagnosis by amniocentesis due to high risks by non-invasive prenatal testing (NIPT) were selected from January 2015 to March 2022 in the Drum Tower Hospital Affiliated to Nanjing University Medical School. The amniotic fluid samples were subjected to chromosomal karyotyping and/or chromosomal microarray analysis. All cases were followed up by searching the birth information or telephone calls, and the results were recorded. 2 test or F test were used for comparing the difference between the groups., Results: Among the 747 pregnant women with a high risk by NIPT, 387 were true positives, and the overall positive predictive value (PPV) was 51.81%. The PPVs for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13) and sex chromosome aneuploidies (SCA) were 80.24% (199/248), 60% (48/80), 14% (7/50) and 38.97% (106/272), respectively. The PPV for T21 was significantly higher than T18 and T13 (χ 2 = 85.216, P < 0.0001). The PPV for other chromosomal aneuploidies and copy number variations (CNVs) were 11.11% (5/45) and 40.74% (22/52), respectively. The PPV for increased X chromosomes was significantly higher than X chromosome decreases (64.29% vs. 22.22%, χ 2 = 5.530, P < 0.05). The overall PPV for elder women (≥ 35 years old) was significantly higher than younger women (69.35% vs. 42.39%, χ 2 = 49.440, P < 0.0001). For T21 and T18, the PPV of Z ≥ 10 group was significantly higher than that for 3 ≤ Z < 5 group or 5 ≤ Z < 10 group (P < 0.05). Among 52 cases with a high risk for CNVs, the PPV for the ≤ 5 Mb group was significantly higher than the 5 Mb < CNVs < 10 Mb or > 10 Mb groups (60% vs. 30%60% vs. 23.53%, P < 0.05). Among the 387 true positive cases, 322 had opted for induced labor, 53 had delivered with no abnormal growth and development, and 12 were lost during the follow-up., Conclusion: The PPVs for common chromosomal aneuploidies are related to the age and Z value of the pregnant women, which were higher in the elder group and higher Z value group. In addition, the PPV is associated with high risk types. The PPV for T21 was higher than T18 and T13, and that for 45,X was lower than 47,XXX, 47,XYY or 47,XXY syndrome. NIPT therefore has relatively high PPVs for the identification of chromosomal CNVs.

Objective: To validate a fetus with high risk for trisomy 13 suggested by non-invasive prenatal testing (NIPT)., Methods: The fetus was selected as the study subject after the NIPT detection at Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences on February 18, 2019. Clinical data of the pregnant woman was collected. Fluorescence in situ hybridization (FISH), chromosomal karyotyping analysis and chromosomal microarray analysis (CMA) were carried out on amniotic fluid and umbilical cord blood and the couple's peripheral blood samples. Copy number variation sequencing (CNV-seq) was also performed on the placental and amniotic fluid samples following induced labor., Results: The pregnant woman, a 38-year-old G4P1 gravida, was found to have abnormal fetal development by prenatal ultrasonography. NIPT test suggested that the fetus has a high risk for trisomy 13. Chromosomal karyotyping analysis of fetal amniotic fluid and umbilical cord blood were 46,XN,add(13)(p10). The result of CMA was arr[hg19]1q41q44(223937972&#95;249224684)×3, with the size of the repeat fragment being approximately 25.29 Mb, the fetal karyotype was thereby revised as 46,XN,der(13)t(1;13)(q41;p10). Chromosomal karyotyping analysis and CMA of the parents' peripheral blood samples showed no obvious abnormality. The CNV-seq analysis of induced placenta revealed mosaicisms of normal karyotype and trisomy 13. The CNV-seq test of induced amniotic fluid confirmed a duplication of chr1:22446001&#95;249220000 region spanning approximately 24.75 Mb, which was in keeping with the CMA results of amniotic fluid and umbilical cord blood samples., Conclusion: NIPT may yield false positive result due to placenta mosaicism. Invasive prenatal diagnosis should be recommended to women with a high risk by NIPT test. And analysis of placenta can explain the inconsistency between the results of NIPT and invasive prenatal diagnosis.

Objective: To assess the value of non-invasive prenatal testing (NIPT) for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies, chromosomal microdeletions and microduplications using cell-free fetal DNA from peripheral blood samples of pregnant women., Methods: A total of 15 237 pregnant women who had undergone NIPT testing at the Maternity and Child Health Care Hospital of Zaozhuang from February 2015 to December 2021 were enrolled in this study. For those with a high risk by NIPT, amniotic fluid samples were collected for G-banding chromosomal karyotyping analysis and chromosomal microarray analysis to verify the consistency of NIPT with results of prenatal diagnosis. All of the women were followed up by telephone for pregnancy outcomes., Results: Among the 15 237 pregnant women, 266 (1.75%) were detected with a high risk for fetal chromosomal abnormality were detected. Among these, 79 (29.7%) were at a high risk for T21, 26 (9.77%) were at a high risk for T18, 9 (3.38%) were at a high risk for T13, 74 (27.82%) were at a high risk for sex chromosome aneuploidies, 12 (4.51%) were at a high risk for other autosomal aneuploidies, and 66 (24.81%) were at a high risk for chromosomal microdeletions or microduplications. 217 women had accepted invasive prenatal diagnosis and respectively 50, 13, 1, 25, 1 and 18 were confirmed with T21, T18, T13, sex chromosome aneuploidies, autosomal aneuploidies and microdeletions/microduplications, and the positive predictive values were 75.76%, 68.42%, 11.11%, 40.32%, 10% and 35.29%, respectively. For 13 042 women (85.59%), the outcome of pregnancy were successfully followed up. During the follow-up, one false negative case of T21 was discovered. No false positive cases for T13 and T18 were found., Conclusion: NIPT has a sound performance for screening T13, T18 and T21, and is also valuable for screening other autosomal aneuploidies, sex chromosome aneuploidies and chromosomal microdeletions/microduplications.

Objective: To analyze the Z values of true and false positive cases by non-invasive prenatal testing (NIPT) in order to improve its accuracy in clinical practice., Methods: Results of 24 384 NIPT tests were reviewed. For cases with high risks for trisomies 21, 18 and 13, the range of Z values in true and false positive cases was analyzed and discussed., Results: A total of 335 high-risk cases were identified by NIPT, among which 256 had elected prenatal diagnosis, 153 (59.77%) were verified as true positives, and 103 (40.23%) were false positives, and the area under the curve (AUC) was 0.9994. For NIPT screening, the positive predictive value (PPV) for trisomy 21 was 100% when Z>13, regardless if the pregnant woman was over 35. When 335 and about 41.6% (5/12) for those<35. For trisomy 18, the PPV was 100% when Z>13, and only 14.3% (1/7) when 3

Objective: To investigate the influence of Z -score and different risk factors on positive predictive value (PPV) of noninvasive prenatal testing (NIPT) for chromosome aneuploidies. Methods: A total of 81 838 NIPT samples from January 1, 2016 to May 31, 2021 in the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed. Invasive prenatal diagnosis was applied to verify the diagnosis of NIPT-positive results and the corresponding PPV was calculated. The PPV of the samples with different Z -score were compared. The women were divided into high-risk group and non-high-risk group: high-risk group ( n =39 114) included those with ultrasound soft index abnormalities, advanced maternal age or high risk for maternal serum screening, while non-high-risk group ( n =42 724) included those with intermediate risk for maternal serum screening or no indications. The differences of the PPV between these two groups were compared. Finally, the comprehensive influence of Z -score and different risk factors on PPV were analyzed. Results: A total of 471 high-risk cases were detected by NIPT results, including 362 cases of trisomy 21, 77 cases of trisomy 18 and 32 cases of trisomy 13. For trisomy 21, trisomy 18 and trisomy 13, there were 226 cases, 46 cases and 6 cases which were confirmed via invasive prenatal diagnosis respectively. The corresponding PPV were 79.3% (226/285), 82.1% (46/56) and 27.3% (6/22), respectively. PPV of trisomy 21 and trisomy 18 were positively correlated with the corresponding Z -score ( r =0.92, 0.62, all P <0.05), while trisomy 13 could not be analyzed due to the small sample size. The PPV of high-risk group was 85.2% (207/243), which was higher than that of the non-high-risk group with PPV of 59.2%(71/120, χ 2 =30.30, P <0.01). When the Z -score was between 3-<4 and 4-<5, the PPV of the high-risk group were 46.2%(12/26)and 62.5%(15/24) respectively, which were higher than those of the non-high-risk group [16.0%(4/25) and 14.3%(3/21), χ 2 =4.10, 8.90, all P <0.05]. With the increase of Z -score, there was no significant difference in PPV between the two groups (all P >0.05). Conclusions: The PPV of trisomy 21 and trisomy 18 are positively correlated with Z -score. The PPV of high-risk group is higher than that of non-high-risk group. The combination of Z -score and other risk factors may provide more accurate genetic counseling for those with NIPT positive results.

Objective: To explore the value of chromosomal microarray analysis (CMA) for the diagnosis of fetuses with high risk signaled by non-invasive prenatal testing (NIPT)., Methods: From June 2017 to August 2019, 628 pregnant women with high risk signaled by NIPT underwent invasive prenatal diagnosis. Amniotic fluid or cord blood samples were subjected to chromosomal karyotyping analysis or CMA. Pregnancy outcome and postnatal conditions of the fetuses were followed up., Results: The positive predictive value for trisomy 21, trisomy 18, trisomy 13, sex chromosome aneuploidy, other rare trisomies and copy number variants (CNVs) among the 628 women were 86.4% (127/147), 41.7% (30/72), 12.9% (4/31), 43.7% (101/231), 16.5% (14/85) and 52.2% (35/67), respectively. In 218 samples with normal karyotype, 5.5% (12/218) of additional pathogenic CNVs and 2.3% (5/218) of loss of heterozygosity were detected by CMA., Conclusion: CMA combined with karyotyping analysis can be used as first-tier test for prenatal diagnosis for women with high-risk signaled by NIPT.

Objective: To assess the performance of non-invasive prenatal testing (NIPT) for the detection of fetal chromosomal aneuploidies and its value for the prevention of birth defects., Methods: In total 28 033 pregnant women underwent NIPT test. The results were compared with that of amniotic fluid and cord blood chromosomal karyotyping analysis. A few cases were verified by array comparative genome hybridization (aCGH). All pregnant women and their fetuses were followed up until after birth., Results: NIPT has indicated a high risk for fetal chromosomal aneuploidies in 186 cases (0.66%), among which 101 (67.33%) were confirmed as 21, 18 and 13 trisomies by invasive prenatal diagnosis, which yielded a diagnostic rate of 86.52%, 50.00% and 19.05%, respectively. The diagnostic rates were 81.28%, 67.85%, 62.79% and 76.00% respectively for those ≥40, ≥35, 25 to 34, and <25. And the diagnostic rates were 65.91%, 60.78%, 71.79% and 80.00% for those over 35, with high risk by prenatal screening, critical risk by prenatal screening and ultrasound abnormality, respectively., Conclusion: The NIPT is effective for screening common chromosomal aneuploidies and preventing births of neonates with trisomy 21, trisomy 18 and trisomy 13.

Objective: To review the results of non-invasive prenatal testing (NIPT) for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13), numerical aberration of sex and other autosomes and copy number variations with a size of >5 Mb., Methods: NIPT was carried out for 44 578 pregnant women. For those with a high-risk by NIPT, amniotic fluid or cord blood samples were collected for G-banding karyotype analysis, and the pregnancy outcome was followed up., Results: Among the 44 578 pregnant women, 466 (1.05%) were diagnosed as high risk of T21 (n = 1359), T18 (n = 178) or T13 (n = 129). Among these, 301, 53 and 20 were subjected to prenatal diagnosis by amniocyte or umbilical blood karyotyping analysis, among which 289 were diagnosed as T21, 40 (75.47%) as T18, and 4 (20.00%) as T13. Among the high-risk pregnant women, 2 cases were diagnosed as Down syndrome after birth, while no trisomy 18 and trisomy 13 were recorded. The sensitivity and specificity of NIPT were T21 (99.31%, 99.97%), T18 (100%, 99.97%), T13 (100%, 99.96%), respectively. The positive predictive values for T21, T18 and T13 by NIPT were 96.01%, 75.47% and 20.00%, respectively., Conclusion: Compared with conventional serological screening and invasive prenatal diagnosis, NIPT has a high sensitivity and specificity for T21, T18 and T13, and has provided an ideal method to screen fetal chromosomal abnormalities.

Objective: To assess the value of non-invasive prenatal testing (NIPT) for the screening of fetal chromosomal abnormalities., Methods: For 12 085 pregnant women, the results of NIPT and invasive prenatal diagnosis were compared., Results: The test was successful in 12 067 cases and has detected 179 chromosomal abnormalities, with a positive rate of 1.48%, sensitivity of 98.39% and specificity of 99.02%. Invasive prenatal diagnosis was performed for 3 of 18 patients who had failed NIPT but has detected no karyotypic abnormality. Except for one case of twin Cesarean section which delivered a normal female fetus and a stillbirth of unknown sex, the remainder of the 18 cases all had a normal delivery. The positive rate of NIPT screening for the abnormal ultrasound group was significant higher than that other groups (P< 0.01). Among those with positive results of NIPT, 122 underwent invasive prenatal diagnosis, and 25 trisomy 21, 7 trisomy 18, 3 trisomy 13, 4 aneuploidies of other autosomes, 13 sex chromosomal aneuploidies and 9 microdeletion/microduplications were confirmed, which yielded a positive predictive rate of 86.21%, 50.00%, 23.08%, 21.05%, 46.43%, and 47.36%, respectively., Conclusion: NIPT has high sensitivity, specificity and positive predictive value, and is an effective method for prenatal screening. In addition to chromosomes 21, 18 and 13, NIPT has certain predictive value for other autosomal aneuploidies, sex chromosomal aneuploidies, microdeletion/microduplications, and can provide a reference for karyotype analysis and chromosomal microarray verification.

Objective: To explore the mechanism of a false-negative result from karyotyping of chorionic villi cells for a trisomy 13 fetus featuring multiple malformations., Methods: For a fetus with multiple malformations by ultrasonography and a 46,XY karyotype by chorionic villi analysis, amniocytes were further analyzed with quantitative fluorescence PCR (QF-PCR), G-banded karyotyping and chromosomal microarray analysis (CMA). Meanwhile, non-invasive prenatal testing (NIPT) was conducted on peripheral blood sample from the pregnant woman to determine the chromosomal composition of cytotrophoblast. After induction of labor, common aneuploidies in placenta and fetal tissue were also analyzed by QF-PCR., Results: QF-PCR, chromosomal karyotyping and CMA analysis of the amniocytes all suggested complete trisomy 13 (47,XY,+13) in the fetus. NIPT also suggested existence of fetal trisomy 13. QF-PCR analysis of the placenta and fetal tissues revealed that cells derived from the maternal surface and right side of fetal surface harbored mosaic trisomy 13, while those derived from other sites of fetal surface of the placenta, umbilical cord, amniotic membrane and fetal muscle tissue harbored trisomy 13., Conclusion: Karyotyping of long-term cultured chorionic villus sample may give rise to false negative results due to placental mosaicism. To ensure accurate prenatal diagnosis, discordance between karyotyping of chorionic villi cells, fetal ultrasound and NIPT result should be verified by amniocentesis or cordocentesis and application of multiple cytogenetic and molecular techniques.