Residual risk of noninvasive prenatal screening in pregnancies with ultrasound anomalies.

OBJECTIVES: To discuss the residual risk (RR) of noninvasive prenatal screening (NIPS) for the mothers with fetal ultrasound abnormalities. METHODS: 880 pregnant women with fetal ultrasound abnormalities accepted prenatal diagnosis by chromosomal microarray analysis (CMA) after amniocentesis. Furthermore, the detection efficiency of NIPS was evaluated and calculated based on our previous studies and other literatures. The RR of the chromosome abnormality results was then analyzed. RESULTS: A total of 103 cases were confirmed as fetal chromosome abnormalities, including 65 (63.1%) of aneuploidies and 38 (36.9%) of clinical significant copy number variations (CNVs). Of which, based on the estimated NIPS efficacy, 87 cases could also be detected by NIPS. The detection rate (DR) was 84.5%, while 16 cases would be missed. The total of RR of NIPS in the fetuses with ultrasound anomalies was 2.0% (16/793), approximately one in 51. The top three RR of fetal ultrasound abnormalities were echogenic bowel (5.9%), multiple systems of structural anomalies (4.5%), and nervous system anomalies (4.2%). CONCLUSION: The overall residual risk of NIPS in the fetuses with ultrasound anomalies was approximately 2.0%, especially in echogenic bowel, multiple systems of structural anomalies and nervous system anomalies.

[Influence of maternal chromosomal abnormalities on non-invasive prenatal testing for fetal sex chromosome aneuploidies].

OBJECTIVE: To study the influence of maternal sex chromosomal abnormalities on the prediction of fetal sex chromosome abnormalities (SCAs) by non-invasive prenatal testing (NIPT). METHODS: Thirty-six pregnant women with a prediction for fetal SCAs by NIPT were verified as false positive after prenatal diagnosis using amniotic fluid samples. With informed consent, these women were subjected to chromosomal karyotyping or copy number variations (CNVs) analysis through high-throughput sequencing. RESULTS: Sex chromosomal abnormalities were found in 8 women, which yielded an abnormal rate of 22.22% (8/36). Among these, 3 had sex chromosome aneuploidies (47, XXX), 4 had sex chromosome mosaicisms, and 1 carried structural chromosomal abnormalities. Reanalysis of the results of NIPT were consistent with the maternal CNVs by large. With the ratio of cffDNA (ChrX)/cffDNA was more than 2, 6 of the eight women were found to harbor sex chromosome abnormalities, and the fetal karyotype was normal. However, with a ratio of less than 2, only 2 of the 38 pregnant women had sex chromosome abnormalities, and 10 of the fetuses were confirmed as positive. CONCLUSION: The presence of maternal sex chromosomal abnormalities can greatly influence the result of NIPT, which may also be an important reason for false prediction for fetal SCAs by NIPT. When NIPT indicates abnormal SCAs, it is necessary to analyze maternal sex chromosomes. The ratio of cffDNA(ChrX)/cffDNA may help to determine the source of abnormal signals.

The failure of non-invasive prenatal testing due to maternal dermatomyositis.

We experienced a case of a pregnant woman who failed to obtain a result from NIPT, due to the high level of total cell-free DNA. A subsequent ultrasound examination discovered that the fetus had severe intrauterine growth restriction, so the woman decided to abort the baby. At the same time, the woman developed slight swelling and tenderness of the proximal interphalangeal and meta-carpophalangeal joints. At first, these symptoms were not noticed, but, when the pregnant woman was admitted to the hospital, her laboratory tests were seriously abnormal, such as serum lactate dehydrogenase (640U/L), creatine phosphor kinase (4525U/L), kinase isoenzyme MB (170U/L), and a hydroxybutyrate dehydrogenase (398U/L). The patient had no other symptoms at this time. Misoprostol and subsequent forceps curettage were used for the induced abortion, a 167-g female fetus was aborted. Fetal skin tissue was taken for chromosomal microarray analysis (CMA) and placenta (biopsied in four places and tested as two composite samples) were taken for postnatal karyotyping to exclude a confined placental mosaicism, chromosomal microarray analysis of the fetal skin tissue revealed that the karyotype was 46, XX, karyotyping of placenta (100 cells) gave results of 46, XX, no abnormalities were detected. Ten days after induction, the patient had developed progressive symmetric muscle weakness in the proximal extremities. Physical examination revealed Gottron's sign and erythema. A manual muscle test showed weakness of the muscles (4/5) of her proximal extremities. Electromyography showed myogenic impairment. After excluding the possibility of neoplasia, the patient was diagnosed with dermatomyositis.

Second-trimester Maternal Serum Screening Biomarkers in the Risk Assessment for Preeclampsia.

To evaluate the predictive value of second-trimester maternal serum screening biomarkers for preeclampsia, we analyzed the second-trimester serum prenatal screening data of pregnant women, and identified preeclampsia diagnosis by hospitalization records. 198 cases who developed preeclampsia and 1171 healthy controls were included in this study. In 15~20 gestational weeks, the cases who developed into preeclampsia had lower serum levels of uE3, uE3 MoM, but higher AFP MoM than controls, while no difference on AFP, fß-hCG, and fß-hCG MoM were found. A higher level of uE3 MoM was associated with a lower risk of preeclampsia (OR=0.35, 95% CI:0.19-0.65, P=0.0009). In addition, threshold effect was observed between preeclampsia and the MoM value of AFP and fß-hCG, the risk of preeclampsia increased when the AFP MoM≥1.43(OR=1.93, 95% CI:1.20-3.11, P=0.0064), or fß-hCG MoM≥2.31(OR=2.59, 95% CI:1.46-4.59, P=0.0012).

[Preliminary analysis of the cause for the failure of non-invasive prenatal testing using cell-free fetal DNA derived from peripheral maternal blood].

OBJECTIVE: To explore the cause of failure of non-invasive prenatal testing (NIPT) using cell-free fetal DNA from peripheral maternal blood. METHODS: A total of 31 832 cases of NIPT were retrospectively analyzed. The clinical data of pregnant women were analyzed and the outcome of pregnancy was followed up. RESULTS: Among the 31 832 cases, 200 patients have failed for the first NIPT test. Second test has succeeded in 171 (85.9%) of 199 cases, while 28 cases (14.1%) still yielded no effective results. This gave rise for a total failure rate of 0.088%. Of the 28 cases, 11 (39.2%) were due to high content of total free DNA and could not be sequenced, 17 (60.7%) were found to have the fetal DNA content of less than 4%. Among the 171 cases which have obtained a valid result, NIPT showed that there were 4 patients with high risk of trisomy 21, 18 cases with high risk of 18 trisomy and 1 case with high risk of 13 trisomy. Karyotyping analysis of the amniocytic chromosomes has identified 3 cases with 47,XN,+21, 1 case with 46,XN,rob(21;21), 1 case with 47,XN,+18, while the 13 trisomy case was found to be false positive. For the 28 cases with failed NIPT retest, 14 had normal delivery, with no anomaly noticed in the neonates. Nine patients had opted for artificial abortion during middle or late pregnancy due to maternal factors (4 cases) or fetal factors (5 cases). Four patients developed complications of pregnancy. One case was in good condition upon follow-up. Four cases were lost during follow-up. Of the 11 pregnant women who had failed the NIPT test due to high content of total free DNA, 6 (54.5%) had opted for artificial abortion during midterm pregnancy, which was significantly higher than that of pregnant women with low free DNA content (17.6%). CONCLUSION: Failure of NIPT testing should attract attention from researchers. Failure of single NIPT test should not be regarded as a high risk signal for fetal chromosomal aneuploidies. For those where the test has failed again, genetic counseling and strengthened perinatal care should be provided for the pregnant women.

[Performance of prenatal screening by non-invasive cell-free fetal DNA testing for women with various indications].

OBJECTIVE To assess the performance of non-invasive prenatal testing (NIPT) based on massive parallel sequencing. METHODS A total of 10 275 maternal blood samples were collected. Fetal chromosomal aneuploides were subjected to low coverage whole genome sequencing. Patients with high risks received further prenatal diagnosis. The outcome of all patients were followed up. RESULTS High-throughput sequencing detected 72 pregnancies with fetal autosomal chromosomal aneuploidy, including 57 cases of trisomy 21, 14 cases of trisomy 18, and 1 case of trisomy 13. The positive predictive value for trisomies 21 and 18 were 98.25% and 91.67%, respectively. Comparing its performance in intermediate or high risk pregnancies, advanced maternal age pregnancies and volunteering to test pregnancies, the positive predictive value were 100%, 95%, 90% and 50%, respectively. The follow up result was only 1 case of 21 trisomy false negative with high risk. For the 56 cases of trisomy 21, the high risk group accounted for 55%, advanced maternal age accounted for 29%, the intermediate risk referred to 14%, the volunteering to test group accounted for 2%. CONCLUSION The performance of NIPT for trisomies 21, 18 and 13 was satisfactory. The method can be used for women with advanced gestational age. NIPT has offered an ideal secondary screening method for those with an intermediate or high risk, and can reduce the rate of birth defects.

Overall evaluation of the clinical value of prenatal screening for fetal-free DNA in maternal blood.

OBJECTIVE: To explore the clinical value of prenatal screening for fetal-free DNA in maternal blood. METHODS: A total of 10,275 maternal blood samples were collected from October 2012 to May 2016 at the prenatal diagnosis center of Changzhou Woman and Children Health Hospital. RESULTS: Among 10,275 pregnant women accepted noninvasive prenatal testing (NIPT), 9 cases could not get the results after collected the blood second times. The rate of NIPT failure was 0.09%. Seventy-two cases got the NIPT positive results of trisomy 21/trisomy 18/trisomy 13, and the detection rate, specificity, positive predictive value (PPV), and false positive rate were 98.59%, 99.99%, 97.22%, and 0.02%. The top-3 indications of the study were advanced age women (34.90%), high risk (25.22%), and intermediate risk (19.56%). They all had the satisfactory results of NIPT. Fifty-seven pregnant women had the high risk of fetal sex chromosomal aneuploidies (SCA). After informed consent, 33 cases accepted prenatal diagnosis. Eighteen cases were confirmed as sex chromosome aneuploidies. The PPV was 54.54%. Compared with other SCA, the PPV of Turner syndrome was lower. One case was false negative after followed up. CONCLUSIONS: NIPT showed a broad application prospects for prenatal screening and diagnosis of fetal chromosomal diseases. We should deepen mining and analyzing the clinical data, and explore the use of NIPT more reasonably from the perspective of evidence-based medicine.

Noninvasive prenatal screening for fetal common sex chromosome aneuploidies from maternal blood.

Objective To explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs). Methods The study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother's peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping. Results The study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17). Conclusion NIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).

Whether Alzheimer's diseases related genes also differently express in the hippocampus of Ts65Dn mice?

BACKGROUND: Down syndrome is a condition which extra genetic material causes delays in child development, both mentally and physically. Strengthening the study of the neural defects of DS is of great significance. METHODS: Ts65Dn mice were used in this study. We removed the brain and isolated their hippocampus. We customized 54 genes in one PCR arrays, included some important genes related to Alzheimer's disease. The expression of genes were detected by RT-PCR. RESULTS: PCR arrays contained 54 genes related to Alzheimer's disease. After real-time PCR, three genes (Nae1, APP and Mapt) expressed differently in the hippocampus of Ts65Dn, compared with the normal mice. Nae1 was decreased significantly, while APP and Mapt were increased obviously. The levels of fold-changes of Nae1, APP and Mapt were 86.19, 4.49 and 2.89 respectively. Significantly different levels of expression were found in the Ts65Dn mice compared with the normal control group (P=0.00 for Nae1, P=0.02 for APP, P=0.01 for Mapt respectively). CONCLUSIONS: There are differential expressed genes in the hippocampus of Ts65Dn mice that may be closely related to Alzheimer's disease. PCR array technology was used in the screening and identification of these genes.