Prenatal diagnosis and outcome of pregnancy for women with high risks by screening of fetal free DNA from peripheral blood samples / 中华医学遗传学杂志

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 (χ2 = 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%, χ2 = 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%, χ2 = 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.

Analysis of genetic etiology and related factors in 1 065 women with spontaneous abortions / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology and related factors in 1 065 women with spontaneous abortions.@*METHODS@#All patients have presented at the Center of Prenatal Diagnosis of Nanjing Drum Tower Hospital from January 2018 to December 2021. Chorionic villi and fetal skin samples were collected, and the genomic DNA was assayed by chromosomal microarray analysis (CMA). For 10 couples with recurrent spontaneous abortions but normal CMA results for abortive tissues, non-in vitro fertilization-embryo transfer (IVF-ET) pregnancies and no previous history of live births and no structural abnormalities of the uterus, peripheral venous blood samples were collected. Genomic DNA was subjected to trio-whole exome sequencing (trio-WES). Candidate variants were verified by Sanger sequencing and bioinformatics analysis. Multifactorial unconditional logistic regression analysis was carried out to analyze the factors that may affect chromosomal abnormality in spontaneous abortions, such as the age of the couple, number of previous spontaneous abortions, IVF-ET pregnancy and history of live birth. The incidence of chromosomal aneuploidies in spontaneous abortions during the first trimester was compared in young or advanced-aged patients by chi-square test for liner trend.@*RESULTS@#Among the 1 065 spontaneous abortion patients, 570 cases (53.5%) of chromosomal abnormalities were detected in spontaneous abortion tissues, which included 489 cases (45.9%) of chromosomal aneuploidies and 36 cases (3.4%) of pathogenic/likely pathogenic copy number variations (CNVs). Trio-WES results have revealed one homozygote variant and one compound heterozygote variants in two pedigrees, both of which were inherited from the parents. One likely pathogenic variant was detected in the patient from two pedigrees. Multifactorial unconditional Logistic regression analysis suggested that age of patient was an independent risk factor of chromosome abnormalities (OR = 1.122, 95%CI: 1.069-1.177, P < 0.001), the number of previous abortions and IVF-ET pregnancy were independent protective factors for chromosomal abnormalities (OR = 0.791, 0.648; 95%CI: 0.682-0.916, 0.500-0.840; P = 0.002, 0.001), whilst the age of husband and history of live birth were not (P > 0.05). The incidence of aneuploidies in the abortive tissues has decreased with the number of previous spontaneous abortions in young patients (χ² = 18.051, P < 0.001), but was not significantly correlated with the number of previous spontaneous abortions in advanced-aged patients with spontaneous abortions (P > 0.05).@*CONCLUSION@#Chromosomal aneuploidy is the main genetic factor for spontaneous abortion, though CNVs and genetic variants may also underlie its genetic etiology. The age of patients, number of previous abortions and IVF-ET pregnancy are closely associated with chromosome abnormalities in abortive tissues.

Fetal RHD screening from circulating cell-free DNA in RhD-negative pregnant women / 中华围产医学杂志

Objective:To investigate the RHD genotypes of RhD-negative pregnant women and explore the optimum strategy for fetal RHD screening among this population in the region. Methods:This prospective study recruited 33 cases of RhD-negative singleton pregnancies at ≥12 weeks of gestation in Nanjing Drum Tower Hospital from March to November 2021. On the basis of RHD genotyping, quantitative real-time polymerase chain reaction (PCR) was used to amplify the exons 5 and 10 of RHD gene in the circulating cell-free DNA of RhD-negative pregnant women harboring whole RHD gene deletion and RHD-CE(2-9)- D. High-throughput sequencing was performed to detect chr1:25648453 locus from circulating cell-free DNA in plasma of RhD-negative pregnant women harboring RHD 1227A mutation to screen the fetal RhD blood group. Neonatal umbilical cord blood samples were collected for verifying fetal RHD genotyping. Descriptive statistical analysis was used. Results:Whole RHD gene deletion homozygous genotype ( n=20, 60.6%), RHD-CE(2-9) -D/whole RHD gene deletion heterozygous genotype ( n=5, 21.2%), RHD 1227A/whole RHD gene deletion heterozygous genotype ( n=7, 15.2%) and RHD 711delC/whole RHD gene deletion heterozygous genotype ( n=1) were identified in the 33 RhD-negative pregnant women. In the 25 cases with whole RHD gene deletion homozygous genotype or RHD-CE(2-9)- D/whole RHD gene deletion heterozygous genotype, 22 fetuses were RhD-positive and three were RhD-negative based on prenatal screening, which were confirmed by the neonatal serological test results after birth. In the seven cases carrying RHD 1227A/whole RHD gene deletion heterozygous genotype, all fetuses were RhD-positive, which were consistent with the results of serological detection after delivery. The case harboring RHD 711delC/whole RHD gene deletion heterozygous genotype did not receive fetal RHD screening. Conclusions:This study suggests that whole RHD gene deletion homozygous genotype is the most common allele in RhD-negative population in this area, followed by RHD 1227A/whole RHD gene deletion heterozygous genotype and RHD- CE(2-9)- D/whole RHD gene deletion heterozygous genotype. For women with whole RHD gene deletion homozygous genotype, RHD- CE(2-9)- D, or RHD 1227A mutation, fetal RHD screening with quantitative real-time PCR and high-throughput sequencing are important for the management of RhD-negative pregnant women.

Efficiency of preeclampsia screening based on biomarkers of aneuploidy screening in first trimester / 中华围产医学杂志

Objective:To evaluate the performance of biomarkers in aneuploidy screening in the first trimester-pregnancy associated plasma protein A(PAPP-A) combined with Fetal Medicine Foundation (FMF)'s competing risk model in screening preeclampsia among our population.Methods:This study was based on a prospective cohort of singleton pregnant women who underwent aneuploidy screening in the first trimester in Nanjing Drum Tower Hospital from January 2017 to September 2020. Mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), and PAPP-A were converted into multiples of median (MoM) using the algorithm disclosed on the website of the FMF (fetalmedicine.org). The predictive outcomes of maternal factors alone or in combination with MAP, UtA-PI, and PAPP-A (alone or in combination) were calculated. Chi-square test, Fisher's exact test or rank sum test were used for comparison among groups and Bonferroni method for pairwise comparisons. Receiver operating characteristic (ROC) curve was used to evaluate the screening efficiency and to calculate the sensitivities of predicting preeclampsia, term and preterm preeclampsia at false-positive rates of 5% and 10%. The predictive performance of this model was further compared to the screening strategy that was recommended in Diagnosis and treatment of hypertension and pre-eclampsia in pregnancy: a clinical practice guideline in China (2020). Results:Among the 5 144 singleton pregnancy women who were recruited in the cohort, 4 919 cases were included and analyzed in this study. A total of 223 cases were diagnosed as preeclampsia (4.5%), including 55 preterm (1.1%) and 168 term preeclampsia (3.4%). The median of MoM values of MAP, UtA-PI, and PAPP-A in the non-preeclampsia group were around 1.0±0.1. Statistical significance was observed in the difference of MAP, UtA-PI, and PAPP-A Mom between women with preterm preeclampsia and those without preeclampsia [1.061 (0.999-1.150) vs 0.985 (0.935-4.043), 1.115 (0.873-1.432) vs 1.039 (0.864-1.236), 0.820 (0.493-1.066) vs 1.078 (0.756-1.508)], which was also seen in the difference of MAP and PAPP-A Mom between women with term preeclampsia and those without preeclampsia [1.065 (1.002-1.133) vs 0.985 (0.935-4.043), 1.007 (0.624-1.393) vs 1.078 (0.756-1.508)] (all P<0.025). The combination screening with maternal factors+MAP+UtA-PI+PAPP-A was noted for the best efficiency. In predicting preeclampsia preterm and term preeclampsia at the false-positive rate of 10%, the sensitivity of the model was 53.0%, 76.4% and 44.6% respectively. Using the screening method recommended in Diagnosis and treatment of hypertension and pre-eclampsia in pregnancy: a clinical practice guideline in China(2020), the proportion of people at high risk of preeclampsia was 5.9% (290/4 919), and the sensitivity for predicting preterm preeclampsia was 25.5% (14/55), which was significantly lower than the combination screening with maternal factors+MAP+UtA-PI+PAPP-A [65.5% (36/55)] when using the same proportion of high-risk population. Conclusion:The preeclampsia screening model based on aneuploidy screening biomarkers in the first trimester--PAPP-A in combination with materral factors, MAP, UtA-PI, can effectively screen preterm preeclampsia in the local population without increasing the laboratory costs.

Practice of clinical application of noninvasive prenatal testing based on cell-free fetal DNA / 中华医学遗传学杂志

OBJECTIVE@#To assess the application value of noninvasive prenatal testing (NIPT) based on cell-free fetal DNA.@*METHODS@#The results of 2777 cases of basic and extended NIPT were retrospectively analyzed. The clinical data and outcome of pregnancy were analyzed, in addition with the diagnosis rate and testing efficiency.@*RESULTS@#Among the 2777 pregnant women, 1192 (42.9%) had accepted basic NIPT and 1585 (57.1%) accepted extended NIPT. With a failure rate of 0.1%, 8 and 6 cases were reported respectively as high-risk pregnancies for trisomy 21 and sex chromosomal abnormalities. Other genetic abnormalities were detected in 32 cases. The positive predictive value for trisomy 21 was 85.7%, and one case of 47,XXX was diagnosed among 3 women with high risks for sex chromosomal abnormalities. For those with a high risk for other genetic abnormalities, pregnant diagnosis rates of basic and extended NIPT were 71.4% (5/7) and 68.2% (15/22), respectively. Seven copy number variations (CNVs) were confirmed, including one pathogenic CNV, one likely pathogenic CNV and 5 variants of unknown significance. Among 6 cases with high-risk of maternal CNVs, 5 fetuses and the mothers were confirmed to be carriers. No CNV was detected in the remainder fetus by chromosomal microarray analysis, while its mother was a carrier of the corresponding CNV.@*CONCLUSION@#NIPT has shown a relatively high positive predictive value for the screening of trisomy 21 and maternal CNVs but with a limited efficiency for the discovery of fetal CNVs. For other genetic abnormalities signaled by NIPT, informed choice by the pregnant women during pre-testing consultation is recommended. Invasive prenatal diagnosis should be considered in the combination of NIPT reports and fetal ultrasound, while the residual risks should be fully informed.

Analysis to the failure rate and causes of noninvasive prenatal testing based on high-throughput sequencing / 中华医学遗传学杂志

OBJECTIVE@#To analyze the cause and pregnancy outcome for non-reportable cell-free DNA (cfDNA) results during non-invasive prenatal testing (NIPT).@*METHODS@#cfDNA was extracted from maternal plasma from 5898 singleton pregnancies at 12 to 22 gestational weeks and underwent NIPT with strict quality control standards. For those with sub-standard results, redraw or invasive prenatal procedures were recommended.@*RESULTS@#Among the 5898 cases, 32 have failed for the initial NIPT, including 17 cases with substandard cffDNA%, 10 cases with data fluctuation after twice library constructing and sequencing, and 5 cases with unidentifiable sex chromosome abnormalities. For these 32 cases, 2 directly underwent amniocentesis, and karyotyping analysis showed both were normal. Six of the 30 redrawn cases finally turned out to be nonreportable. The final nonreportable rate was therefore 0.1% (8/5898). Of the redrawn cases, 1 trisomy 21, 1 trisomy 18 and 1 trisomy 13 high risk-cases were identified, which were all confirmed to be false positive. Among the 6 nonreportable cases, 2 women underwent invasive prenatal testing, and 1 was found to have a normal fetal karyotype, while another was found to have an abnormal karyotype of mos45,X[32]/46,XY[18]. The other 4 nonreportable cases who did not accept invasive prenatal testing have all reported normal child development at follow-up.@*CONCLUSION@#The main reason for nonreportable NIPT results was low cffDNA%. The high success rate of the redrawn cases has effectively increased the overall NIPT success rate and reduced the number of the cases necessitating invasive prenatal diagnosis. The initially nonreportable women may consider retesting after careful counseling with informed consent.

Effects of gestational weight gain at different stages on pregnancy complications / 中华围产医学杂志

Objective:To investigate the effects of gestational weight gain (GWG) at different stages on pregnancy complications such as preeclampsia, gestational hypertension, gestational diabetes mellitus(GDM), small for gestational age (SGA), and large for gestational age (LGA).Methods:This was a prospective longitudinal cohort study. Singleton pregnancies at 11-13 +6 weeks of gestation in the Affiliated Drum Tower Hospital, Medical School of Nanjing University from January 2017 to November 2019 were recruited. The maternal height, weight, blood pressure, and fetal ultrasonic parameters were measured at 19-23 +6, 29-34 +6, and 35-40 +6 weeks of gestation by face-to-face interview and the pregnancy outcomes were followed up. All participants were grouped by body mass index (BMI) in the first trimester, with <18.50 kg/m 2 as underweight group, 18.50-23.99 kg/m 2 as normal group, ≥24.00 kg/m 2 as overweight/obesity group. Chi-square test and rank-sum test were adopted for comparison among groups. Weekly weight gain was converted into Z scores, and insufficient, appropriate, and excessive weight gain were respectively defined when Z<-1, -1≤ Z≤1, and Z>1. The effect of weekly weight gain at different gestational trimesters on pregnancy complications was analyzed by binary logistic regression. Results:Totally, 4 143 pregnant women entered the cohort. After excluding 327 cases, 3 816 were finally included in the analysis, with 394 in underweight group, 2 668 in normal group, and 754 in overweight/obesity group. Excessive weekly weight gain in the early second trimester was a risk factor for LGA( aOR=1.78, 95% CI:1.31-2.42, P<0.001), and in the later second trimester it was associated with preterm preeclampsia ( aOR=3.00, 95% CI: 1.26-7.10, P=0.013), gestational hypertension ( aOR=2.38, 95% CI: 1.44-3.94, P=0.001), and LGA ( aOR=1.59, 95% CI: 1.15-2.22, P=0.005). In the third trimester, excessive weekly weight gain was associated with higher risks of term preeclampsia ( aOR=2.70, 95% CI: 1.61-4.54, P<0.001) and gestational hypertension ( aOR=1.84, 95% CI: 1.05-3.21, P=0.033); while insufficient weekly weight gain was a risk factor for SGA ( aOR=1.58, 95% CI: 1.01-2.48, P=0.045), but a protective factor for term preeclampsia ( aOR=0.37, 95% CI: 0.14-0.97, P=0.041). Insufficient and excessive weekly weight gain in the early second trimester were not related to GDM (both P>0.05). Conclusions:GWG at different stages has different effects on pregnancy complications. A more relaxed control of GWG in the early second trimester combined with strict control in both the later second trimester and the third trimester may be a reasonable strategy to reduce the risk of preeclampsia without increasing the risk of SGA.

Research progress on fetal RHD genotype screening in RhD-negative pregnant women in Asia / 中华围产医学杂志

RhD-negative pregnant women with an RhD-positive fetus are at risk of hemolytic disease of the fetus and newborn (HDFN), which may lead to fetal/neonatal death. While these would not affect those RhD-negative fetuses. With the advancement of technology in genetics, the administration of anti-D immunoglobulin to women with an RhD-positive fetus could reduce the risk of HDFN. Therefore, non-invasive prenatal testing on fetal RHD genotype plays an important role in the management of RhD-negative pregnant women. Selective usage of anti-D immunoglobulin is important in perinatal management in these women. The non-invasive prenatal screening for fetal RHD gene which has been carried out in Caucasian is not applicable to Asians because of the difference in RHD genotype. In addition to complete or partial RHD gene deletion, point mutations are also common RHD genotypes among Asians. This enlightens us to establish a non-invasive prenatal screening method for Asians. This article reviews the progress of fetal RHD screening in Asian RhD-negative pregnant women.

Prospective cohort study of fetal nuchal translucency in first-trimester and pregnancy outcome / 中华妇产科杂志

Objective@#To explore the relationship between fetal nuchal translucency (NT) in the first trimester and pregnancy outcome.@*Methods@#A prospective cohort study was conducted in Nanjjing Drum Tower Hospital from December 2015 to December 2018, 4 958 singleton pregnant women were enrolled to screen fetal ultrasound structure and serology in the first trimester, ultrasound in the second trimester and neonatus physical examination 28 days after birth. According to the results of NT, 167 cases of fetus with increased NT (≥3.0 mm) and 4 791 cases of normal NT were divided, moreover, 86 cases with isolate increased NT and 81 cases of increased NT combined with structural abnormality. The prognosis of fetuses with different NT thickness was analyzed, and the pregnancy outcome of fetuses with isolate increased NT or combined with structural abnormality were analyzed. In the first trimester, if the fetal structure was abnormal or the serological screening result was high risk, the chromosomal microarray analysis (CMA) would be performed by chorionic villus sampling to determine the prenatal diagnosis.@*Results@#(1) The pregnancy outcome for fetus of normal NT: there were 4 791 cases with normal NT. Totally, 4 726 cases with normal NT and no structural abnormalities were screened out in the firsttrimester. In this group, 5 cases of aneuploidies were diagnosed based on high risk of maternal serum biomarkers and 83 cases of structural abnormalities were screened out in the subsequent ultrasound scan and the neonatal examination. Another 65 cases with normal NT present complicated with structural anomalies were screened out in the first trimester and 4 cases were diagnosed as aneuploidies. (2) The pregnancy outcome for fetus of isolate increased NT: 66 (76.7%, 66/86) cases of isolated increased NT were performed CMA, 3 cases were diagnosed as trisomy 21 and terminated pregnancy. Another 4 cases were terminated pregnancy privately without cytogenetic diagnosis. No further anomalies were found in 79 cases till 6 to 21 months postnatally. (3) The pregnancy outcome for fetus of increased NT with structural anomalies: increased NT present with structural anomalies were screened out by detailed anomaly scan in the first trimester and 32 of them were confirmed as aneuploidies. In this group, 70 cases terminated pregnancy, 2 cases had spontaneous miscarriages and 9 cases had liveborns (1 newborn was found ventricular septal defect). (4) The pregnancy outcome for fetus of increased NT with or without structural anomalies: the percentage of aneuploidies in fetuses with isolated increased NT (3.5%, 3/86) was significantly lower than those with structural abnormalities (39.5%,32/81). The healthy survival rate in fetuses with isolated increased NT (91.9%,79/86) was significantly higher than those with structural abnormalities (9.9%, 8/81).@*Conclusions@#A detailed first-trimester anomaly scan could improve prenatal screening efficiency of birth defects. Compared to the fetuses with increased NT combined with structural abnormalities, the healthy survival rate of fetuses with isolated increased NT based on detailed first-trimester anomaly scan is higher and the percentage of fetal aneuploidies is lower.

Prospective cohort study of fetal nuchal translucency in first-trimester and pregnancy outcome / 中华妇产科杂志

Objective:To explore the relationship between fetal nuchal translucency (NT) in the first trimester and pregnancy outcome.Methods:A prospective cohort study was conducted in Nanjjing Drum Tower Hospital from December 2015 to December 2018, 4 958 singleton pregnant women were enrolled to screen fetal ultrasound structure and serology in the first trimester, ultrasound in the second trimester and neonatus physical examination 28 days after birth. According to the results of NT, 167 cases of fetus with increased NT (≥3.0 mm) and 4 791 cases of normal NT were divided, moreover, 86 cases with isolate increased NT and 81 cases of increased NT combined with structural abnormality. The prognosis of fetuses with different NT thickness was analyzed, and the pregnancy outcome of fetuses with isolate increased NT or combined with structural abnormality were analyzed. In the first trimester, if the fetal structure was abnormal or the serological screening result was high risk, the chromosomal microarray analysis (CMA) would be performed by chorionic villus sampling to determine the prenatal diagnosis.Results:(1) The pregnancy outcome for fetus of normal NT: there were 4 791 cases with normal NT. Totally, 4 726 cases with normal NT and no structural abnormalities were screened out in the firsttrimester. In this group, 5 cases of aneuploidies were diagnosed based on high risk of maternal serum biomarkers and 83 cases of structural abnormalities were screened out in the subsequent ultrasound scan and the neonatal examination. Another 65 cases with normal NT present complicated with structural anomalies were screened out in the first trimester and 4 cases were diagnosed as aneuploidies. (2) The pregnancy outcome for fetus of isolate increased NT: 66 (76.7%, 66/86) cases of isolated increased NT were performed CMA, 3 cases were diagnosed as trisomy 21 and terminated pregnancy. Another 4 cases were terminated pregnancy privately without cytogenetic diagnosis. No further anomalies were found in 79 cases till 6 to 21 months postnatally. (3) The pregnancy outcome for fetus of increased NT with structural anomalies: increased NT present with structural anomalies were screened out by detailed anomaly scan in the first trimester and 32 of them were confirmed as aneuploidies. In this group, 70 cases terminated pregnancy, 2 cases had spontaneous miscarriages and 9 cases had liveborns (1 newborn was found ventricular septal defect). (4) The pregnancy outcome for fetus of increased NT with or without structural anomalies: the percentage of aneuploidies in fetuses with isolated increased NT (3.5%, 3/86) was significantly lower than those with structural abnormalities (39.5%,32/81). The healthy survival rate in fetuses with isolated increased NT (91.9%,79/86) was significantly higher than those with structural abnormalities (9.9%, 8/81).Conclusions:A detailed first-trimester anomaly scan could improve prenatal screening efficiency of birth defects. Compared to the fetuses with increased NT combined with structural abnormalities, the healthy survival rate of fetuses with isolated increased NT based on detailed first-trimester anomaly scan is higher and the percentage of fetal aneuploidies is lower.

Health economic evaluation of five prenatal screening strategies for Down's syndrome / 中华围产医学杂志

ObjectiveTo investigate the cost-effectiveness and cost-benefit of five screening strategies for Down syndrome (DS) to optimize prenatal screening strategy.MethodsA retrospective analysis was conducted in 26803 gravidas, who underwent the second trimester maternal serum screening ( maternal serumα-fetoprotein andβ-human chorionic gonadotropin) from 2002 to 2003, whom were classified into three groups according to the results of serum DS screening: high risk group (≥1/270), borderline risk group (≥1/1000-<1/270) and elderly gravida group (age at expected date of confinement≥35 years old). TreeAge Pro 2011 sofware was used to set up the decision tree model for cost-effectiveness and cost-benefit analysis. Strategy 1: Maternal serum screening was carried out on all gravidas, and then prenatal diagnosis was performed for women in high risk group. Strategy 2: Non-invasive prenatal testing (NIPT) was carried out on all gravidas, and then prenatal diagnosis was offered for women with positive or suspected results. Strategy 3: NIPT was only carried out on gravidas of advanced maternal age and maternal serum screening was performed on the rest population. Gravidas with positive or suspected positive results in NIPT or classified into the high risk group underwent prenatal diagnosis. Strategy 4: Maternal serum screening was carried out on all gravidas. Those at high risk received prenatal diagnosis, while those at borderline risk underwent NIPT first and followed by prenatal diagnosis if positive or suspected positive NIPT results were identified. Strategy 5: Maternal serum screening was carried out on all gravidas. Those at high or borderline risk would undergo NIPT followed by prenatal diagnosis if they were positive or suspected positive for NIPT.Results(1) Among 26803 gravidas, 1244 were at high risk group (4.64％) with five having trisomy 21; 3925 were at bordelrine risk (14.64％) with four having trisomy 21; 300 women were of advanced age (1.12％) with one having trisomy 21. (2) Cost-effectiveness analysis: the incremental cost-effectiveness ratios of strategy 3 and 4 were negative and that of strategy 1 was 0 with a cost-effectiveness ratio of 15833764.53. The incremental cost-effectiveness ratio of strategy 2 was 49865746.10, which was far greater than that of strategy 5 (63049.56). The cost-effectiveness ratio of strategy 4 is 586703.63, which was less than those of strategy 1,2 and 3 but higher than that of strategy 5. The average cost-effectiveness ratio of strategy 5 was the lowest (508431.20) among these five strategies, which meant that for every diagnosis of DS, strategy 5 had the lowest cost (508400 yuan). (3) Cost-benefit analysis: The benefits of strategy 4 and 5 were greater than their costs. Strategy 5 had the highest benefit-cost ratio, followed by strategy 4, 2, 3 and 1. (4) When other factors remained unchanged and only the acceptance rate of prenatal diagnosis was adjusted from 50％ to 100％, strategy 1 had the least cost expectation, followed by strategy 3, 5, 4 and 2. When the cost of NIPT was below 82.4 yuan, the cost expectation of strategy 2 that performed on all gravidas was the lowest, while when it was between 82.4 and 1827.2 yuan, the screening cost of strategy 5 was the lowest.ConclusionsStrategy 5 has the best cost-effectiveness and cost-benefit. It would be the best screening strategy for DS, if the cost of NIPT is between 82.4-1827.2 yuan.

Detection of a recurrent de novo mutation in a Chinese family affected with Duchenne muscular dystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide genetic analysis for a family affected with Duchenne muscular dystrophy (DMD) with a recurrent de novo mutation.</p><p><b>METHODS</b>Multiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the DMD gene, and the DNA products were sequenced on a Genetic Analyzer 3130 sequencer. Haplotype analysis was performed using four short tandem repeat polymorphism loci (44C/A, 45C/A, 49C/A and 63C/A) of the DMD gene for the family.</p><p><b>RESULTS</b>A same deletional mutation (Del 48-50) of the DMD gene was detected in the proband and fetus, but not in their mother. The proband and fetus have inherited the same haplotype of the DMD gene from their mother. The fetus was predicted to be affected by the disease.</p><p><b>CONCLUSION</b>Above findings suggested that the mother was very likely to have a germline mosaicism for the DMD gene mutation. For the de novo DMD mutation, although genetic analysis of peripheral blood DNA has indicated that the proband's mother was not a carrier, germline mosaicism could still not be ruled out, and prenatal gene diagnosis should be provided for subsequent pregnancies.</p>

Clinical indications and detection efficiency of non-invasive prenatal testing in 13 041 cases from Jiangsu Province, China / 中华围产医学杂志

Objective To determine the clinical indications and detection efficiency of non-invasive prenatal testing (NIPT) in Jiangsu Province, China. Methods A total of 13 041 pregnant women from nine hospitals in Jiangsu Province who voluntarily accepted NIPT for chromosome 13, 18, 21 and sex chromosome from January 1, 2012 to December 31, 2013 were analyzed retrospectively. All cases were singleton pregnancies and spontaneously conceived. Invasive prenatal diagnosis followed by fetal chromosome karyotype analysis was recommended in high-risk women following NIPT. The clinical indications and positive predictive value of NIPT were conducted. Results NIPT detected 88, 19, 9 and 64 cases at high risk for trisomy 21, trisomy 18, trisomy 13 and X chromosome aneuploidy, and the positive rate was 0.67%, 0.15%, 0.07% and 0.49%, respectively. Among the 74, 13, 8 and 44 high-risk cases who accepted chromosome karyotype analysis, respectively, 67 cases were diagnosed with trisomy 21, 12 cases with trisomy 18, one case with trisomy 13, and 18 cases with numerical X chromosome abnormality. The positive predictive value was 90.5% (67/74), 12/13, 1/8 and 40.9% (18/44), respectively. One pregnant woman who was reported as high-risk trisomy 21 following NIPT, but high-risk trisomy 18 at prior serum screening, was eventually diagnosed with fetal trisomy 18 by chromosome karyotype analysis, whose placenta was a mosaic of trisomy 21 and trisomy 18. High-risk following serum screening was the most common indication for NIPT accounting for 46.4% (6 056/13 041), followed by low-risk but asking for testing (28.9%, 3 773/13 041) and advanced age (20.5%, 2 673/13 041). Conclusions High-risk, low-risk but asking for testing and advanced maternal age are common indications for NIPT in Jiangsu Province. The positive predictive value of NIPT for trisomy 21 or trisomy 18 is relatively high, but is much lower for trisomy 13 or X chromosome aneuploidy.

Application of different technologies for distinguishing true and pseudo mosaicisms during prenatal diagnosis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To use different technologies to distinguish true and pseudo mosaicisms among cultured amniocytes in order to attain more accurate diagnosis.</p><p><b>METHODS</b>With informed consent, 20 mL of amniotic fluid was obtained from pregnant women at between 18 to 24 gestational week. Each amniotic fluid sample was processed as two separate lines for the culturing, observation, harvesting and analysis. All procedures were conducted conforming to the Technology Standards of Cytogenetic Prenatal Diagnosis of Fetal Chromosome Abnormalities issued by the Ministry of Health in 2010. Umbilical cord blood, fluorescence in situ hybridization (FISH), single nucleotide polymorphism array (SNP-array) and flow cytometer were applied when necessary.</p><p><b>RESULTS</b>Among 3910 cases, 128(3.3%) were detected as mosaicisms. Further analysis with the above technologies has verified 6 cases as true mosaicisms and the remaining 120 as pseudomosaicisms. For one case detected by karyotype analysis as 47, XXY/46, XY, the ratio of different cell lines was confirmed by FISH as 1:2. Another case, detected by karyotype analysis as 47, XX,+mar/46, XX (1:1), was verified by SNP-array as 18p duplication. A suspected polyploidy mosaicism was rejected by flow cytometry and cord blood karyotyping.</p><p><b>CONCLUSION</b>Two separate cell cultures are important for distinguishing true and pseudo mosaicisms. Combined FISH, SNP-array and flow cytometry can attain more reliable and accurate diagnosis for mosaicisms.</p>

Detection rate of chromosomal abnormalities in women with different indications for invasive prenatal diagnosis and procedure-related complications / 中华围产医学杂志

Objective To discuss the detection rate of chromosomal abnormalities in women with different indications for invasive prenatal diagnosis(amniocentesis and eordocentesis), and the procedure-related complications. Metheds A retrospective analysis was conducted on 1264 women, who underwent invasive prenatal diagnosis (1082 amniocentesis and 182 eordocentesis), and the procedure-related complications were reviewed. Results The indications for invasive prenatal diagnosis in these 1264 women were: increased risk at prenatal screening (651, 51.5%), advanced maternal age (≥35) (318, 25.2%), abnormal foundings through uhrasonograph (136, 10.8%),history of adverse pregnancy (88, 6.9%), one or two abnormal serologic markers (52,4.1%), and chromosomal balance translocation carrier in either one of the couple(19, 1.5%). Thirty-seven cases were found to be chromosomal abnormalities with clinic significance and the indications for them were: ultrasonic abnormality (20/136, 14.7%); increased risk at prenatal screening (12/651, 1.8%); one or two abnormal serologic markers (1/52, 1.9%); history of adverse-pregnant (1/88, 1.1%)chromosomal balance translocation carrier in either one of the couple (3/19, 15.8%); advanced maternal age (0/318). Among the 1264 cases, 5 experienced spontaneous abortion and the procedure-related fetal loss rates were 0.28% for amniocentesis (3/1082) and 1.09% for cordocentesis (2/182), P=0. 154. The rate of complications after cordocentesis was significantly higher than amniocentesis (9.89 % vs 0.18 %, P= 0.0001). Conclusions Routine fetal karyotyping should be prompted after prenatal ultrasonographic abnormalities. However, invasive prenatal diagnosis due to advanced maternal age alone is controversial. Amniocentesis is the fist choice for invasive prenatal diagnosis.