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After the promulgation of the first edition of expert consensus on the application of chromosomal microarray analysis (CMA) technology in prenatal diagnosis in 2014, after 8 years of clinical and technical development, CMA technology has become a first-line diagnosis technology for fetal chromosome copy number deletion or duplication abnormalities, and is widely used in the field of prenatal diagnosis in China. However, with the development of the industry and the accumulation of experience in case diagnosis, the application of CMA technology in many important aspects of prenatal diagnosis, such as clinical diagnosis testimony, data analysis and genetic counseling before and after testing, needs to be further standardized and improved, so as to make the application of CMA technology more in line with clinical needs. The revision of the guideline was led by the National Prenatal Diagnostic Technical Expert Group, and several prenatal diagnostic institutions such as Peking Union Medical College Hospital were commissioned to write, discuss and revise the first draft, which was discussed and reviewed by all the experts of the National Prenatal Diagnostic Technical Expert Group, and was finally formed after extensive review and revision. This guideline is aimed at the important aspects of the application of CMA technology in prenatal diagnosis and clinical diagnosis, from the clinical application of evidence, test quality control, data analysis and interpretation, diagnosis report writing, genetic counseling before and after testing and other work specifications are elaborated and introduced in detail. It fully reflects the integrated experience, professional thinking and guidance of the current Chinese expert team on the prenatal diagnosis application of CMA technology. The compilation of the guideline for the application of CMA technology in prenatal diagnosis will strive to promote the standardization and advancement of prenatal diagnosis of fetal chromosome diseases in China.

Objective: To summarize the clinical efficacy and nursing experience of intrauterine blood transfusion (IUT) treatment for fetal anemia cases., Methods: The clinical data of 4 fetal anemia cases receiving IUT in Beijing Obstetrics and Gynecology Hospital, Capital Medical University between 2020 and 2022 were collected. Four pregnant women aged 24-38 years were included in the study. They carried fetuses with anemia of unknown causes. The four pregnant women developed anxiety after they were informed of the diagnosis of fetal anemia. One-on-one psychological counseling before the IUT procedure and one-on-one companionship over the course of the surgery were provided for the pregnant women. In addition, they were closely monitored for blood transfusion reactions. Postprocedural observation of the puncture site and 24-hour monitoring of the newborns were also conducted., Results: The four pregnant women underwent 1-3 times of IUT in the second and third trimesters, with the minimum gestational age at the time of IUT being 25 + weeks and the blood transfusion volume being 20-107 mL/time. Two pregnant women experienced irregular uterine contractions during IUT in the third trimester. Other than that, all other IUT treatments were successful. After IUT, there was a significant improvement in fetal hemoglobin, peak systolic velocity of the middle cerebral artery (MCA-PSV), and cardiothoracic area ratio. One case did not give birth in our hospital and the outcome of the fetus was not known. The other three fetuses achieved good outcomes., Conclusion: Positive preprocedural psychological counseling for pregnant women, close intraoprocedural and postprocedural pregnancy monitoring, and the prevention of maternal and fetal complications are the key to improving the clinical efficacy of IUT and achieving a good fetal outcome., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).)

Objective: To analysis the clinical characteristics of 400 fetuses with heart defects and the impactors of pregnancy decision making, and explore the influence of a multi-disciplinary team (MDT) cooperation approach on it. Methods: Clinical data of 400 fetuses with abnormal cardiac structure diagnosed at Peking University First Hospital from January 2012 to June 2021 were collected, which were divided into 4 groups according to the characteristics of fetal heart defects and the presence of extracardiac abnormalities or not: single cardiac defects without extracardiac abnormalities (122 cases), multiple cardiac defects without extracardiac abnormalities (100 cases), single cardiac defects with extracardiac abnormalities (115 cases), and multiple cardiac defects with extracardiac abnormalities (63 cases). The types of fetal cardiac structural abnormalities and genetic test results, and the detection rate of pathogenic genetic abnormalities, MDT consultation and management situation, and pregnancy decision of fetuses in each group were retrospectively analyzed. A logistics regression was used to analyze the influencing factors of fetal heart defects pregnancy decision. Results: (1) Among the 400 fetal heart defects, the four most common major types were ventricular septal defect 96 (24.0%, 96/400), tetralogy of Fallot 52 (13.0%, 52/400), coarctation of the aorta 34 (8.5%, 34/400), and atrioventricular septal defect 26 (6.5%, 26/400). (2) Among the 204 fetuses undergoing genetic examination, 44 (21.6%, 44/204) pathogenic genetic abnormalities were detected. (3) Detection rate of pathogenic genetic abnormalities (39.3%, 24/61) and pregnancy termination rate (86.1%, 99/115) in the single cardiac defects with extracardiac abnormalities group were significantly higher than those in the single cardiac defects without extracardiac abnormalities group [15.1% (8/53), 44.3% (54/122), respectively] and the multiple cardiac defects without extracardiac abnormalities group [6.1% (3/49), 70.0% (70/100), respectively, both P< 0.05], and the pregnancy termination rate in the multiple cardiac defects without extracardiac abnormalities group and the multiple cardiac defects with extracardiac abnormalities group (82.5%,52/63) were significantly higher than that of the single cardiac abnormalities without extracardiac abnormalities group (both P <0.05). (4) After adjusting for age, gravity, parity and performed prenatal diagnosis, maternal age, the diagnosis of gestational age, prognosis grades, co-existence of extracardiac abnormalities, presence of pathogenic genetic abnormalities, and receiving MDT consultation and management were still independent influencing factors of termination of pregnancy of fetuses with cardiac defects (all P <0.05). A total of 29 (7.2%, 29/400) fetal cardiac defects received MDT consultation and management, and compared with those without MDT management, the pregnancy termination rate in the multiple cardiac defects without extracardiac abnormalities group [74.2%(66/89) vs 4/11] and the multiple cardiac defects with extracardiac abnormalities group [87.9%(51/58) vs 1/5] were lower, the differences were statistically significant respectively (all P <0.05). Conclusions: Maternal age, diagnosed gestational age, severity of cardiac defects, extracardiac abnormalities, pathogenic genetic abnormalities and MDT counseling and management are the influencing factors of fetal heart defects pregnancy decision. MDT cooperation approach influences pregnancy decision-making and should be recommended for the management of fetal cardiac defect to reduce unnecessary termination of pregnancy and improve pregnancy outcomes.

Objective: To explore the clinical application value and accuracy of cell-free fetal DNA (cff-DNA) technique in prenatal screening. Methods: The results of quantitative fluorescent PCR (QF-PCR) and karyotype of amniotic fluid cells were analyzed retrospectively in 2 398 monocyesis pregnant women who had been amniocentesis at the First Affiliated Hospital of Zhengzhou University from May 2013 to December 2019, and the results of 359 cases who had been examined by single-nucleotide polymorphism array (SNP array). Results: Cff-DNA test of 2, 398 cases indicated 987 cases of trisomy 21, 351 cases of trisomy 18, 135 cases of trisomy 13, 566 cases of sex chromosome abnormality, and 359 cases of other chromosome abnormality. Chromosome karyotype analysis detected 826 cases of trisomy 21, 213 cases of trisomy 18, 17 cases of trisomy 13, 221 cases of sex chromosome abnormality, and 26 cases of other chromosome abnormality. The detection rate were 83.69% (826/987), 60.68% (213/351), 12.59% (17/135), 39.04% (221/566) and 7.24% (26/359), respectively. QF-PCR detected 1 046 cases of trisomy and 188 cases of sex chromosomes abnormality, and the detection rate was 99.05% (1 046/1 056) and 85.07% (188/221), respectively. Compared with the abnormal number detected by chromosome karyotype analysis, 10 cases of trisomeric chimerism and 24 cases of sex chromosome were missed by QF-PCR. Among the 359 other chromosomal abnormalities detected by SNP array, 64 cases were consistent with the results of cff-DNA, and the detection rate was 17.83% (64/359), which was 10.59% higher than the karyotype result. Conclusions: Karyotype analysis is the gold standard for diagnosing chromosomal abnormalities. QF-PCR could diagnose common chromosome aneuploidy rapidly and accurately, and it could be used as an auxiliary detection technique for karyotype analysis. The incidence of sex chromosome chimerism is high, so missed diagnosis should be warned. SNP array could be given priority to verify chromosome microdeletion or microduplication detected by cff-DNA.

Objective: To assess the value of genetic testing for Fragile X syndrome (FXS)., Methods: A domestically made diagnostic kit based Tri-primer-PCR method was used to detect mutations of the FMR1 gene among 6 pedigrees with unexplained intellectual disability. The results were verified by methylation PCR and Southern blotting., Results: Pedigrees 1 and 6 were positive for the screening. In pedigree 1, a full-mutation allele with methylation was identified in the proband and his mother, which was passed on to the fetus. In pedigree 6, the proband was mosaic for a full-mutation allele and a pre-mutation allele. His sister was asymptomatic with a full-mutation. His mother carried pre-mutation allele, while his father and sister's baby were normal. The number of CGG repeats of the pedigrees 2 to 5 were in the normal range., Conclusion: Genetic testing can provide an effective way to prevent FXS caused by FMR1 mutations and enable prenatal diagnosis for families with a high risk for the disease.

Objective: To explore the genetic basis for fetuses with cleft lip and palate., Methods: For 100 fetuses diagnosed with cleft lip with or without palate, G-banding chromosomal karyotyping and copy number variation sequencing (CNV-seq) were carried out on chorionic villi, amniotic fluid or cordocentesis samples., Results: No genomic abnormality was found among 49 fetuses with isolated cleft lip and palate, while 12 genomic aberrations were found among 51 fetuses with syndromic cleft lip and palate, which included 4 cases with trisomy 13, 2 cases with trisomy 18, 1 with X chromosome aneuploidy, 2 with other chromosomal aneuploidies and 3 with pathogenic CNVs., Conclusion: The incidence of genomic abnormalities in fetuses with cleft lip and palate was high. In addition to chromosomal abnormalities, attention should also be paid to pathogenic CNVs.

Objective: To provide prenatal diagnosis for a pregnant woman with a history of Williams-Beuren syndrome pregnancy., Methods: The karyotypes of the fetus and his parents were analyzed with routine G-banding. Their genomic DNA was also analyzed with array comparative genomic hybridization (aCGH)., Results: No karyotypic abnormality was detected for the fetus and his parents. aCGH has identified a de novo 5.09 Mb deletion at 2p13.3-p12 in the fetus., Conclusion: The 2p13.3-p12 microdeletion carried by the fetus was de novo. As it has involved dosage-sensitive genes SPR and DCTN1, the deletion is probably pathogenic.

Objective: To apply high-throughput sequencing for the detection of potential mutation in a methylmalonic academia pedigree for which no proband was available., Methods: For a couple who had previously given birth to an affected child, 14 genes were re-sequenced by high-throughput sequencing. Suspected mutations were validated by Sanger sequencing. Specific mutations were tested for amniotic fluid sample from the fetus., Results: High-throughput sequencing suggested that the husband has carried a heterozygous mutation of the MUT gene (Exon 3: c.729&#95;730insTT; p.Asp244Leufs*39), while the wife also carried a heterozygous mutation of the MUT gene (Exon 5: c.914T>C; p.Leu305Ser). Both mutations were confirmed by Sanger sequencing. Testing of amniotic sample suggested that the fetus has carried neither mutation. Follow-up has found no sign of methylmalonic academia in the neonate., Conclusion: High-throughput sequencing is a sensitive method to screen a bunch of genes in a single test. For autosomal recessive diseases, when no proband is available, carrier testing for both parents with high-throughput sequencing can provide an alternative approach, though great caution should be taken in the setting of prenatal diagnosis.

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.

Objective: To report on prenatal diagnosis and follow up of two patients with paternal uniparental disomy of chromosome 6 (pUPD6)., Methods: Fetal cells were subjected to in situ culturing and G-banded chromosomal analysis. DNA samples of the fetuses and their parents were also analyzed with single nucleotide polymorphism microarray (SNP array)., Results: Both fetuses had a normal male karyotype. SNP array analysis showed both have carried pUPD6., Conclusion: pUPD6 can lead to transient neonatal diabetes mellitus type 1. Homozygous status of recessive mutations, disorder of gene imprinting, and its influence on placental function are the main factors to be considered during prenatal diagnosis and genetic counseling for pUPD6.

Objective: To assess the value of whole-genome amplification (WGA) and next generation sequencing (NGS) for the pre-implantation screening of discarded embryos., Methods: In total 476 discarded embryos were collected. After continued culture, 23 high-quality blastocysts were obtained. Blastocysts graded as 4BC or above based on Gardner classification were subjected for blastula biopsy. Five to ten nourish ectoderm cells were hatched with a biopsy needle. Following WGA and NGS, deletion and/or duplication of chromosomal fragments and numerical chromosomal aberrations were analyzed., Results: In total 148 trophoblast cells were obtained from the 23 blastocysts. Following WGA, 60 amplification products were selected for NGS. The results showed that there were 39 abnormal chromosomes derived from 14 blastocysts, which gave an abnormal rate of blastocyst of 60.87% (14/23)., Conclusion: WGA combined with NGS can enable pre-implantation genetic screening for discarded embryos, which may improve the efficacy of in vitro fertilization as well as reduce the risk for birth defects.

Objective: To assess the application value in prenatal diagnosis using karyotype analysis combined with BACs-on-Beads (BoBs) assay., Methods: Nine hundred sixty five pregnant women were subjected to amniocentesis, chromosomal karyotype analysis and detection of BoBs were employed simultaneously for abnormal number of chromosomes and 9 chromosome microdeletion syndrome in prenatal diagnosis., Results: Fifty cases common chromosome aneupoidies were successfully detected by both karyotype analysis and BoBs which included 31 cases of trisomy 21,10 cases of trisomy 18 and 9 cases with sex chromosome abnormality. BoBs in addition detected 1 case of DiGeorge-1 microdeletion syndrome and 1 case of 7q11.23 microduplication syndrome. All 9 fetuses with chromosome abnormalities detected by karyotyping were missed by BoBs, including 2 cases of marker chromosomes,4 cases of chromosomal translocation,1 case of chromosomal inversion, 2 cases of Sex chromosome mosaicism; 2 cases of fetal inherited from the parents,7 cases for novel mutations., Conclusion: Karyotype analysis combined with BoBs dedtection is a rapid, effective and highly accurate prenatal diagnosis model that may should be widely used in clinical diagnosis.

Objective: To perform prenatal diagnosis for a fetus with endocardial cushion defect and explore its mechanism., Methods: The karotypes of the fetus and its parents were analyzed by routine G-banding. Their genomic DNA was also analyzed by array comparative genomic hybridization (aCGH)., Results: The fetus and its mother were found to have a karyotype of 46, XX, inv(8)(p21q24.1), while no karyotypic abnormality was detected for the father. aCGH has detected a 15.14 Mb deletion at 8p23.3-p22 and a 6.87 Mb duplication at 8q24.23-q24.3 in the fetus., Conclusion: The fetus was diagnosed with Rec8 syndrome. Its abnormal chromosomes have derived from the inv(8) carried by its mother. GATA4 and SOX7 may be the key genes for the endocardial cushion defect found in the fetus.

Objective: To assess the value of single nucleotide polymorphism array (SNP array) for the study of fetuses with conotruncal defects (CTD) detected by echocardiography., Methods: SNP array was carried out on 75 fetuses with sonographically detected CTD but a normal karyotype. The results were analyzed with ChAS software., Results: Pathogenic CNVs were detected in 7 (9.3%) of all cases. Variant of uncertain significance (VOUS) was detected in 2 (2.7%) cases. Benign CNVs were detected in 19 (25.3%) cases., Conclusion: SNP array is an effective method for delineating the etiology of fetuses with CTD, particularly for those with a normal karyotype.

OBJECTIVE To assess the value of BAC-on-Beads(BoBs) technology combined with conventional chromosomal karyotyping for reducing birth defects. METHODS For 690 women with singleton pregnancy and indication for prenatal diagnosis, aneuploidies of chromosomes 13, 18, 21, X and Y, in addition with 9 microdeletions and microduplications, were detected with the BoBs assay. And the results were compared with that of conventional karyotyping of amniocytes. RESULTS Karyotyping analysis attained a positive rate of 6.08% (42/690), which included 36 aneuploidies and 6 structural aberrations. The BoBs assay attained a detection rate of 5.95% (41/689). In addition to all chromosomal aneuploidies detected by conventional karyotyping, the Bobs assay has detected 3 cases with Xp22 region microdeletions, 1 case with 22q11 segment duplication, and 1 case with 5p15 microduplication. No balanced translocation or chromosomal polymorphisms was detected. CONCLUSION BoBs technique combined with conventional karyotyping is suitable for rapid diagnosis of a large number of prenatal cases and increasing the detection rate for fetal chromosomal abnormalities.

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.

Objective: To analyze the outcome of chromosomal microarray analysis (CMA) in prenatal diagnosis for fetal abnormalities detected by ultrasonography., Methods: Amniotic fluid samples from 477 pregnancies with abnormal ultrasound findings but without common aneuploidies were detected by CMA with Affymetrix CytoScan 750K arrays. The results were analyzed with ChAS v3.0 software., Results: Among the 477 samples, 24 (5.03%) were detected with pathogenic copy number variations (pCNVs) by CMA. Six (9.68%) among 62 cases with structural fetal abnormalities in multiple organ systems were detected with pCNVs, 11 (7.48%) among 147 cases with a single structural anomaly were detected with pCNVs, and 7 (2.61%) among 268 cases with a soft marker were detected with pCNVs., Conclusion: CMA has offered a clear advantage over conventional karyotyping for the detection of fetal chromosomal abnormalities, and can provide an effective diagnostic tool for those with one or more structural abnormalities detected by ultrasound.

Objective: To use next generation sequencing (NGS) to identify unknown abnormality of chromosome 9 in a fetus and explore its mechanism., Methods: A pregnant woman with abnormal fetal ultrasound finding underwent amniocentesis for G-banded chromosomal analysis. Karyotyping was also performed on peripheral blood samples derived from its parents. Fetal blood sample was obtained for NGS testing to identify abnormality unrecognized by karyotyping., Results: Analysis of amniocytes has revealed a 46,XX,der(9)(?::p21 to qter) karyotype, while both parents had a normal karyotype. NGS analysis of the fetus revealed a 20.67 Mb duplication (4 454 279-25 126 275) at 9p21.3p24.2, which overlapped with that of the 9p duplication syndrome, and a 4.43 Mb deletion at 9p24.2p24.3 (10 001-4 442 364), which partially overlapped with that of 9p deletion syndrome and 46,XY sex reversal 4 region. Comparison of the sequencing data with reference genome database indicated direct duplication of 9p21.3p24.2, which was also supported by review of the morphology of chromosome 9p. Therefore, the karyotype of the fetus was verified to be 46,XX,der(9) dir dup(9)(p21.3p24.2), del(9)(p24.2p24.3)., Conclusion: Combined G-banded karyotyping and NGS can identify dir dup del(9p) with accuracy. Delineation of the mechanism of dir dup del(9p) and its genotype-phenotype correlation may facilitate genetic counseling and estimation of recurrence risk.

Objective: To carry out mutation analysis and prenatal diagnosis for 12 families affected with hearing loss and enlarged vestibular aqueduct from southern Zhejiang province., Methods: Clinical data and peripheral venous blood samples of 38 members from the 12 families were obtained. Mutations of 4 genes, namely SLC26A4, GJB2, c.538C to T and c.547G to A of GJB3, m.1555A to G and m.1494C to T of 12S rRNA, were detected by PCR and Sanger sequencing. Maternal contamination was excluded by application of STR detection during prenatal diagnosis., Results: Among the probands from the 12 families, 11 were found to be compound heterozygotes or homozygotes and 25 were heterozygotes. All of the families were detected with IVS7-2A to G mutations, and 4 had a second heterozygous mutation (c.2168A to G of the SLC26A4 gene). Four rare pathogenic mutations, namely IVS5-1G to A, c.946G to T, c.1607A to G and c.2167C to G, were detected in another four families. In addition, the partner of proband from pedigree 3 was identified with compound heterozygous mutations of c.235delC and c.299-300delAT, and proband of pedigree 5 has carried a mutation of c.109G to A in GJB2. For SLC26A4 gene, prenatal diagnostic testing has revealed heterozygous mutations in 6 fetuses and compound heterozygous mutations in 2 fetuses., Conclusion: IVS7-2A to G and c.2168A to G of the SLC26A4 gene were the most common mutations in southern Zhejiang. Such mutations can be found in most families affected with hearing loss and enlarged vestibular aqueduct, which may facilitate genetic counseling and prenatal diagnosis for such families.

Objective: To analyze mutations of IDUA gene in two pedigrees affected with mucopolysaccharidosis type I and provide prenatal diagnosis for them., Methods: The 14 exons of the IDUA gene were subjected to PCR amplification and Sanger sequencing., Results: For pedigree 1, the proband was found to harbor compound heterozygous mutations c.46-57delTCGCTCCTGGCC (p.Ser16&#95;Ala19del) of exon 1 and c.1147delC (p.Arg383Alafs*57) of exon 8 of the IDUA gene, which were inherited from his father and mother, respectively. The latter was unreported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.46-57delTCGCTCCTGGCC mutation. For family 2, the proband was also found to carry compound mutations of the IDUA gene, namely c.721T to C (p.Cys241Arg) of exon 6 and c.1491delG (p.Thr497fs27) of exon 8, which were inherited from her mother and father, respectively. Neither mutation was reported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.721T to C mutation., Conclusion: Mutations of the IDUA gene probably underlie the MPS-I in both pedigrees. Above results have enriched the spectrum of IDUA gene mutations and facilitated prenatal diagnosis for both families.

Objective: To delineate the phenotypic characteristics of 22q11.2 deletion syndrome and the role of CRKL gene in the pathogenesis of cardiac abnormalities., Methods: G-banded karyotyping, single nucleotide polymorphism (SNP) array and fluorescence in situ hybridization (FISH) were performed on a fetus with tetralogy of Fallot detected by ultrasound. Correlation between the genotype and phenotype was explored after precise mapping of the breakpoints on chromosome 22q11.2. SNP array was also performed on peripheral blood samples from both parents to clarify its origin., Results: The fetus showed a normal karyotype of 46,XY. SNP array performed on fetal blood sample revealed a 749 kb deletion (chr22: 20 716 876-21 465 659) at 22q11.21, which encompassed the CRKL gene but not TBX1, HIRA, COMT and MAPK1. Precise mapping of the breakpoints suggested that the deleted region has overlapped with that of central 22q11.2 deletion syndrome. SNP array analysis of the parental blood samples suggested that the 22q11.21 deletion has a de novo origin. The presence of 22q11.21 deletion in the fetus was also confirmed by FISH analysis., Conclusion: Central 22q11.21 deletion probably accounts for the cardiac abnormalities in the fetus, for which the CRKL gene should be considered as an important candidate.

Objective: To screen for genomic copy number variants (CNVs) in a fetus with one sibling affected with Prader-Willi syndrome using single nucleotide polymorphism (SNP) array., Methods: The fetus and its parents were subjected to chromosomal karyotyping and SNP array analysis., Results: A 5p15.33 microdeletions was identified in the fetus and its phenotypically normal mother with a size of 344 kb (113 576 to 457 213). The father was normal for both testing. Analysis of literature and CNVs database indicated the above CNV to be variant of unclear significance. The couple decided to continue with the pregnancy and gave birth to a healthy boy at full-term. No abnormalities were found during the follow-up., Conclusion: This study may provide further data for the phenotype-genotype correlation of 5p15.33 microdeletion, which differs from Cri du Chat syndrome.

Objective: To assess the accuracy of copy number variations (CNVs) detection by non-invasive prenatal testing (NIPT) in addition to its routine targets and clinical significance of such CNVs for the reduction of fetuses born with chromosomal microdeletion/duplication syndromes., Methods: From October 2014 to October 2015, 14 235 pregnant women volunteered to participate in the study. Fifteen cases detected with chromosomal CNVs by the NIPT decided to undergo prenatal diagnostic procedures including amniocentesis, G-banded karyotyping and chromosomal microarray analysis (CMA). All such cases were routinely followed up after birth., Results: Among the 14 235 subjects underwent NIPT, 18 cases were detected with Down syndrome, 4 with trisomy 18, and 2 with trisomy 13, in addition with 24 cases of CNVs. For the latter, 15 (including 11 cases with microdeletions and 4 cases with microduplications) participated in further prenatal diagnosis. In 13 cases (86.7%), the results of CMA were consistent with those of NIPT. On the other hand, only 7 out of the 15 cases showed a positive result with karyotyping, suggesting a rather high rate of missed diagnosis (46.2%). Of note, karyotyping has identified partial inversion of chromosome 9 in one case., Conclusion: As a screening tool, NIPT has a high accuracy for the detection of CNVs. However, as this method is still under improvement, it is more of a reminder rather than a diagnostic tool with full capability.

Objective: To explore the value of a novel prenatal diagnosis model using combined chromosomal karyotyping and BACs-on-Beads TM (BoBs), a newly-developed technique., Methods: 1048 single pregnancy pregnant women with various diagnostic indications were performed amniocentesis for prenatal diagnosis with karyotyping and BoBs simultaneously., Results: Among 1047 successfully cultured specimens, 50 chromosomal abnormalities were identified with BoBs, including 43 common chromosomal trisomies, 3 chimeric chromosomes and 4 structural abnormalities, of which 3 microdeletions/microduplications were not detected with karyotyping. Except for extra yield of 1 Robertsonian translocation, the other numerical chromosomal abnormalities were detected with both karyotyping and BoBs. Ten fetal chromosome abnormalities were confirmed with karyotyping, including 8 structural abnormalities and 2 chimeric chromosomes., Conclusion: Combination of karyotyping and BoBs turned out to be a rapid, complementary and effective diagnostic model for fetal chromosomal abnormalities and microdeletion syndromes, which could yield a higher detection rate of fetal chromosomal abnormalities and chromosomal microdeletions/microduplications.

Objective: To explore the origin and mechanism of small supernumerary marker chromosomes (sSMC) in order to facilitate genetic counseling., Methods: Chromosome karyotypes of two fetuses and their immediate family members were analyzed by conventional G banding. High-throughput whole genome sequencing was used to determine the origin of sSMCs., Results: Fetus 1 was shown to have a karyotype of 47,XY,+mar but with normal FISH and B ultrasound findings. Its father also had a 47,XY,+mar karyotype with normal FISH results and clinical phenotype. High-throughput genome sequencing revealed that fetus 1 and its father were both 46,XY,dup(21)(q11.2;q21.1) with a 6.2 Mb duplication of the long arm of chromosome 21. The fetus was born with normal phenotype and developed well. Its grandmother also had a karyotype of 46,XX,t(15;21)(q13;p13) with normal FISH result and clinical phenotype. The karyotypes of its mother and grandfather were both normal. Analysis of fetus 2 showed a 47,XY,+mar karyotype with normal FISH results. High-throughput genome sequencing suggested a molecular karyotype of 46,XX. The fetus was born with normal phenotype and developed well. The karyotypes of its parents were both normal., Conclusion: Considering their variable origins, identification of sSMC should combine conventional G banding analyses with high-throughput whole genome sequencing for precise delineation of the chromosomes.

Objective: To explore the application of combined techniques for the prenatal diagnosis of a case with 7q11.23 duplication., Methods: Amniocentesis was performed in the second trimester for a mother with a high risk suggested by serological prenatal screening. G-banded chromosomal analysis was performed on cultured amniocytes and peripheral blood samples from both parents. DNA from amniotic fluid sample was isolated for a BACs-on-Beads (BoBs) assay. To define the range of duplication, copy number variation was determined with single nucleotide polymorphism array (SNP array, Affymetrix CytoScan 750K) and fluorescence in situ hybridization (FISH) analysis., Results: Chromosomal analysis suggested that the fetus and both parents all had a normal karyotype, while a duplication of 7q11.23 was detected by the BoBs assay. SNP array revealed a 1.5 Mb duplication in chromosome 7q11.23, which was confirmed by FISH., Conclusion: Combined prenatal BoBs, SNP array and FISH has enabled effective diagnose of a case with 7q11.23 syndrome.

Objective: To establish a method for the prenatal diagnosis of 22q11 microdeletion syndrome., Methods: BACs-on-Beads (BoBs) and fluorescence in situ hybridization (FISH) were performed on a fetus for whom amniotic chromosomal culturing has failed and a pair of twin fetuses suspected for 22q11 deletion syndrome., Results: 22q11 microdeletion was detected in all 3 fetuses by prenatal BoBs as well as FISH, with only one red signal detected at the DiGeorge/VCFS N25 site and two green signals on the 22q13.3 ARSA site., Conclusion: The combination of prenatal BoBs and FISH can provide a method for the prenatal diagnosis of 22q11 microdeletion.

Objective: To apply single nucleotide polymorphism microarray (SNP array) for the detection of genome-wide copy number variations(CNVs) in fetuses with malformations and women with an adverse reproductive history, and to explore the correlation of rare CNVs with the clinical manifestations., Methods: Amniotic fluid and umbilical cord blood samples were collected from 314 women with singleton pregnancy. SNP array was performed on samples where chromosomal abnormalities were excluded after G-banding analysis., Results: Pathological CNVs were detected in 8.91% (28/314) of all samples, which included 11 duplications, 9 deletions, 4 loss of heterozygosity (LOH), and 4 conjoined deletions and duplications. The sizes of duplications and deletions were between 0.47 Mb and 16.7 Mb, and between 0.16 Mb and 13.3 Mb, respectively. Fifteen CNVs were mapped to the regions of microdeletion or microduplication syndromes or regions associated with clinical manifestations, while the remainder 13 were considered benign or variant of uncertain significance., Conclusion: A proportion of fetuses with malformations and women with an adverse reproductive history may be attributed to CNVs, half of which are mapped with to the regions of well known syndromes. SNP array may facilitate discovery of new syndromes and provide a basis for genetic counseling and prenatal diagnosis.

Objective: To use combined G-banding and array-comparative genomic hybridization (aCGH) for the prenatal diagnosis of a fetus with 5q35 deletion syndrome., Methods: Chromosomal karotypes of the fetus and parents were analyzed with G-banding analysis. aCGH was performed to detect minor chromosomal structural abnormalities., Results: The karyotype of the fetus was ascertained as 46, XY, t(5;10)(q35;p13), and the karyotypes of the parents were normal. aCGH has identified a de novo 1.68 Mb deletion at 5q35.2q35.3 and a 1.44 Mb duplication at 10p14p13., Conclusion: aCGH has a higher resolution and greater accuracy for mapping chromosomal aberrations and is a useful supplement for G banding karyptyping analysis.

Objective: To explore the genetic etiology of fetal abnormalities detected by prenatal ultrasound through single nucleotide polymorphism (SNP array) analysis., Methods: Two hundred and eight fetuses were tested with SNP array and conventional karyotyping. Complex copy number variations (CNVs) were verified with fluorescence in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA) and quantitative fluorescence polymerase chain reaction (QF-PCR)., Results: For the 208 cases, the diagnostic yields of conventional karyotping and SNP assay were 8.2%(17/208) and 13.9%(29/208), respectively. For fetuses with malformations of the cardiovascular system, central nervous system or multiple systems, pathogenic CNVs was detected in 4.6% (8/174), 2.3%(4/174), and 1.1% (2/174) of all fetuses, respectively. No pathogenic CNVs was detected among those with abnormalities of the renal system, digestive system, skeletal system, facial dysmorphism or respiratory system., Conclusion: CNVs are significantly related with birth defects. Compared with conventional karyotyping, SNP array is a better platform for CNVs detection and can provide more clues for genetic counseling, recurrence risk assessment and prenatal diagnosis.

Objective: To report on a sporadic case of Lowe syndrome diagnosed prenatally with ultrasound examination and genetic testing., Methods: Detailed sonographic fetal screening was performed by an experienced sonographer at 32 weeks of gestation. Fetal cranial magnetic resonance imaging (MRI) was applied to detect potential brain abnormality. Chromosomal microarray analysis (CMA) was conducted on amniotic fluid sample from the fetus and peripheral blood sample from the mother., Results: Congenital cataract and enlarged posterior fossa were detected by fetal ultrasound screening. Fetal cranial MRI found hypoplasia of the gyrus. CMA revealed that the fetus has carried a 633 kb deletion at Xq25-26.1 which encompassed the OCRL gene. The mother was a carrier of the same deletion. Clinical examination after birth confirmed that the neonate was affected with Lowe syndrome in addition with an atrial septal defect., Conclusion: Prenatal diagnosis of Lowe syndrome without a family history largely depends on fetal imaging. Should cataract be found by ultrasound screening, fetal MRI may be considered to rule out central nervous system anomalies. CMA assay should also be considered to facilitate the diagnosis.

Objective: To assess the value of G-banded karyotyping in combination with multiplex ligation-dependent probe amplification (MLPA) as a tool for the detection of chromosomal abnormalities in fetuses with congenital heart defects., Methods: The combined method was used to analyze 104 fetuses with heart malformations identified by ultrasonography. Abnormal findings were confirmed with chromosomal microarray analysis (CMA)., Results: Nineteen (18%) fetuses were found to harbor chromosomal aberrations by G-banded karyotyping and MLPA. For 93 cases, CMA has detected abnormalities in 14 cases including 10 pathogenic copy number variations (CNVs) and 4 CNVs of uncertain significance (VOUS). MLPA was able to detect all of the pathogenic CNVs and 1 VOUS CNV., Conclusion: Combined use of G-banded karyotyping and MLPA is a rapid, low-cost and effective method to detect chromosomal abnormalities in fetuses with various heart malformations.

Objective: To investigate the genetic cause and prognosis of a fetus with a rare karyotype., Methods: Fluorescence in situ hybridization (FISH) was used for verifying a structural chromosomal abnormality detected by conventional karyotyping analysis. Whole genome DNA microarray was used to analyze copy number variations carried by the fetus., Results: The fetus was found to have a 46,XX,dup(21)(?q21q22) karyotype, which was verified by FISH analysis as repetition of chromosome 21 region, namely nuc ish 21q22×3. Whole genome DNA microarray confirmed that there was a 17.87 Mb duplication in the 21q21.3q22.3 region, which involved GATA1, JAK2 and ALL genes and spanned the Down syndrome region. The genes are implicated in craniofacial abnormalities, cardiac abnormalities, mental retardation, growth retardation, limb abnormalities. In addition, there was also an 8.43 Mb deletion in the 4p16.1p16.3 region, which involved FGFR3, LETM1, WHSC1 and WHSC2 and other 64 OMIM genes and spanned the Wolf-Hirschhorn syndrome region. The genes are implicated in growth retardation, craniofacial abnormalities, cardiac abnormalities, mental retardation, and hypotonia. After consultation, the family chose to terminate the pregnancy at 25th week of gestation., Conclusion: FISH can help to verify structural chromosome abnormalities suspected by conventional karyotyping analysis. Combined with whole genome microarray, these can determine copy number variation and its region containing the disease genes, and facilitate clinical analysis of the fetus.

Objective: To investigate the application of fetuses with talipes equinovarus(TE)using chromosomal microarray analysis(CMA)technology., Methods: From May 2012 to June 2015, 54 fetuses were found with TE and with or without other structural anomalies by prenatal ultrasound. Karyotyping was taking for them all, and the fetuses with normal karyotypes took another CMA test. The data were analyzed with CHAS software. Finally all the cases were followed up to know about their pregnancy outcomes., Results: One of the 54 cases was detected with abnormal karyotype which was trisomy 18(2%, 1/54). CMA was undertaken to the remaining fetuses, they were divided into 2 groups, including isolated TE group(n= 38)and complex TE group(n=15). The detection rate of clinical significant copy number variations(CNV)by CMA was 11%(6/53), while isolated and complex TE group were 5%(2/38)and 4/15, respectively(P= 0.047). Of the 53 cases, 51 cases were successfully followed up. Eleven cases were found without TE after birth, and the false positive rate(FPR)of TE was 22%(11/51)., Conclusions: Whole-genome high-resolution CMA increased the detection rate by 11% in fetuses with TE. With the FPR and the detection rate of the clinical significant CNV of 2 groups, whole-genome CMA could be recommended to the fetuses with complex TE group but normal karyotypes. A series of ultrasonic tests should be suggested to the isolate TE group, while with the abnormal ultrasound, fetuses would be suggested to have CMA test for decreasing the rates of invasive prenatal diagnosis and FPR.

Objective: To investigate the clinical value of echocardiography combined with genetic testing in the fetal cardiac rhabdomyoma., Methods: Thirty-three fetal cardiac rhabdomyoma cases diagnosed by fetal echocardiogram in Beijing Anzhen Hospital from Jan. 2011 to Oct. 2015 were enrolled in a retrospective analysis. The results of other examination and pregnancy outcomes of them were followed up, the genetic characteristics of cardiac rhabdomyoma were summarized on the basis of pathology and genetics examination results., Results: The pregnancy outcomes: 24 cases were terminated pregnancy, 4 cases were born and 5 cases were lost. The results of ultrasound, pathology and genetic examination were detailed in 8 cases. Pathological examination: the typical characteristics of cardiac rhabdomyoma were found in the 8 cases with cardiac rhabdomyoma. The tumor tissue was composed of irregular and swelling shape of cardiomyocytes, and the cytoplasm was vacuole like, which was characteristic of " spider like cells" through microscopic observation. The geneticdetection results: 7 cases had tuberous sclerosis complex (TSC) gene mutation, TSC gene abnormalities were not detected in 1 case. Among the 7 cases with TSC gene mutations, 6 cases were with TSC2 gene mutation and the other 1 case was with TSC1 gene mutation. The family gene was investigated in the 5 cases, which including 3 cases of TSC gene mutation in mother passed on to the fetus (1 case with family of three generations of genetic) and 2 cases of spontaneous TSC gene mutation in the fetus., Conclusions: Prenatal echocardiography combined with genetic detection have important clinical significance, which not only can clear if cardiac rhabdomyomas were associated with TSC, but also can clear the TSC gene mutation source. So as to further guide the perinatal management.

Objective: To investigate the clinical value of prenatal MRI in the diagnosis and differential diagnosis of congenital bronchopulmonary sequestration (BPS)., Methods: From January 2009 to December 2014, 16 fetuses with BPS were diagnosed by fetal MRI in Huzhou Maternity and Child Care Hospital and Shanghai Children's Medical Center Affiliated to Shanghai Jiaotong University School of Medicine. The clinical data of these cases were analyzed retrospectively. All were singleton pregnancy, and MRI was carried out within 24-48 hours after routine prenatal ultrasound. All the neonates underwent postnatal enhanced CT scan or surgical biopsy after birth, and the results were compared to prenatal MRI diagnosis., Results: (1) With prenatal MRI, 16 cases were diagnosed BPS. The lesions located in left lung in 10 cases, and right lung in 6 cases. As the scope of the lesion, 3 cases located in the whole left lung, 6 cases limited to the left lower lobe, and 1 case was subdiaphragmatic on the left side. 2 cases located in the whole right lung and 4 cases limited to the right lower lobe. One case complicated oligoamnios, and one had pleural effusion. Supplying vessels could be found in 14 cases. (2) When the postnatal results were compared with prenatal MRI, 15 cases were comfirmed as BPS (15/16), including 10 intralobar cases 5 extralobar cases. One that was diagnosed as BPS by prenatal MRI was confirmed to be congenital cystic adenomatoid malformation (CCAM) by pathology. The accuracy of prenatal MRI diagnosis of BPS was 15/16. Prenatal ultrasound missed one case and misdiagnosed two cases, as one was mistakened as CCAM and the other as cystic teratoma., Conclusion: Prenatal MRI has good clinical value in the diagnosis and differential diagnosis of fetal BPS.

Objective: To verify the diagnosis of Angelman syndrome(AS) in a proband in order to provide prenatal diagnosis for his family., Methods: Array comparative genome hybridization(array-CGH) and fluorescence in situ hybridization(FISH) on metaphase chromosomes were performed., Results: The karyotype of the proband was normal, and a regional deletion of 15q11.1-11.2 was detected by array-CGH. FISH analysis has confirmed loss of heterozygosity in 15q11.2. No positive results were obtained by array-CGH or karyotype analysis. Amniotic fluid sample was taken from the proband's mother upon her subsequent pregnancy. The karyotype of the fetus was normal, but SNP microarray chip analysis has identified loss of heterozygosity in 8p23.1-p22. As no abnormality was observed by ultrasound and other prenatal examinations, the pregnancy was recommended to continue to full-term, and a healthy infant was born., Conclusion: Clinically suspected AS can be diagnosed by array-CGH and FISH. The result may facilitate accurate genetic counseling and prenatal diagnosis for the affected family.

Objective: To compare the results of fluorescence in situ hybridization (FISH) assay and conventional karyotyping analysis for the detection of chromosomal aneuploidies., Methods: In total 2607 amniotic fluid samples were subjected to an improved FISH technique. Meanwhile, karyotype analysis was also ordered for each sample., Results: Of the 2607 samples, 62 abnormalities were identified by FISH, which included 62 cases of trisomy 21, 5 cases of 45,X, 12 cases of trisomy 18, 3 cases of trisomy 13, and 1 case of 47, XYY. Conventional karyotyping analysis has identified 63 cases of trisomy 21, 5 cases of 45,X, 12 cases of trisomy 18, 3 cases of trisomy 13, 1 case of 47, XYY, and 57 cases of balanced translocations. The success rate of FISH detection was 98.4% for trisomy 21, and 100% for 45,X, trisomy 18 and trisomy 13., Conclusion: For the detection of chromosomal aneuploidies, FISH assay is quick, simple, accurate and can reduce workload when aminocyte culture has failed. As an auxiliary method for amniocytic analysis, it can provide reference for the consultation of those with advanced age and high pregnancy risk.

Objective: To investigate the prenatal ultrasonic manifestations of fetal gray matter heterotopias (FGMH) and evaluate the optimal method its prenatal diagnosis., Methods: The prenatal and postnatal ultrasound images and MRI images were analyzed for a fetus with a definitive diagnosis of FGMH. The detection rates of FGMH by prenatal ultrasound and MRI reported in literature were compared., Results: We identified 11 reports of FGMH from 1998 to 2015, involving 43 cases with prenatal diagnoses. Of the total of 44 cases (including our case), 32 that had been confirmed postpartum had prenatal ultrasound and MRI data, which showed a significantly lower detection rates of FGMH by prenatal ultrasound than by MRI (43.8% vs 93.8%, P<0.001)., Conclusion: Prenatal ultrasound can only detect subependymal heterotopia with characteristic manifestations, and the detection of other types of FGMH relies on MRI, which is currently the best option for prenatal diagnosis of FGMH.

Objective: To explore the genetic cause for a fetus with structural anomaly, and to correlate the phenotype with the genotype., Methods: Amniotic fluid was obtained following the revelation of structural anomaly by ultrasonography. Cell culture and direct DNA extraction were performed in parallel. G-banded karyotyping analysis and chromosome microarray analysis (CMA) were subsequently carried out., Results: G-banded karyotyping has suggested the fetus to be a normal male. However, CMA analysis has revealed the presence of a mosaic 3.24 Mb duplication of 1p36.33p36.32 (24%) and uniparental disomy (UPD) of chromosome 6. The genetic diagnosis for the fetus was therefore 46,XY, arr 1p36.33 p36.32(849,466-4,090,472)×2-3, (6)×2 hmz. The anomaly can probably explain the ultrasound findings in the fetus., Conclusion: Compared with conventional cytogenetic methods, CMA has greater resolution and throughput, and can serve as a more efficient platform for the detection of chromosomal microdeletion, microduplication, loss of heterozygosity and UPD.

Objective: To detect chromosomal imbalance in a fetus with complex congenital heart disease, and to correlate the genotype with the phenotype., Methods: Routine G-banding was carried out to analyze the karyotypes of the fetus and its parents, and single nucleotide polymorphisms array (SNP-array) was used for delineating fine genomic aberrations. The detected aberrations were confirmed with multiplex ligation-dependent probe amplification (MLPA)., Results: The fetus and its parents all showed a normal karyotype, while array-SNP has detected a 13.87 Mb duplication at 4p16.3-p15.33 and a 15.65 Mb deletion at 11q23.3-q25 in the fetus. The results were confirmed by the MLPA assay., Conclusion: The partial trisomy 4p (Wolf-Hirschhorn syndrome) and partial monosomy 11q (Jacobsen syndrome) probably underlie the complex heart defects detected in the fetus. Analysis of the karyotypes of its parents offered no help for the determination of the aberrant type and recurrent risk. Compared with routine karyotype analysis, aberrant regions can be identified with array-SNP with greater resolution and accuracy. This has provided useful information for prenatal diagnosis and genetic counseling.

Objective: To provide genetic analysis for a family affected with Duchenne muscular dystrophy (DMD) with a recurrent de novo mutation., Methods: 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., Results: 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., Conclusion: 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.

Objective: To explore the value of next-generation sequencing for the non-invasive prenatal testing of fetal chromosomal aneuploidies., Methods: Plasma from 4004 women with singleton pregnancy at a gestational age between 12-35(+5) weeks was collected prior to amniocentesis between April 19th 2011 and December 31st 2013. The samples were divided into three groups: (1) High risk for Down syndrome by biochemical screening; (2) Advanced maternal age; (3) Abnormalities by ultrasound or other methods. Plasma DNA extracted from above samples was sequenced at low coverage. Positive results were verified against the karyotypes of the fetuses. For those with negative results, the fetuses were followed up by telephone call for at least six months after birth., Results: Among 4003 samples subjected to non-invasive prenatal diagnosis, 66 (1.65%) had a positive result. In group 1, 22 cases of trisomy 21 (T21), 3 cases of trisomy 18 (T18), 1 case of 13 trisomy (T13), 8 cases of 45,X and 2 cases of other chromosomal abnormality were detected. In group 2, 13 cases of T21, 2 cases of T18, 1 case of T13, 5 cases of 45,X, 2 cases of 47,XXN and 1 case of other chromosomal abnormality were detected. In group 3, 1 case of T21, 1 case of T18, 1 case of T13, and 3 cases of 47,XXN were detected. For 55 samples underwent prenatal diagnosis, 30 cases of T21 and 4 cases of T18 were discovered, which was consistent with the results of non-invasive prenatal diagnosis. For the 13 cases indicated as 45,X, 3 were verified by karyotype analysis, 2 were verified as mosaicism (45,X/46,XN), 8 were 46,XN (false positives). For the 5 cases indicated as 47,XXN, 2 were verified by karyotype analysis, the other 3 were 46,XN (false positives). Karyotypes of 3 cases suspected for other chromosomal abnormalities were all verified as 46,XN (false positive). Until May 1st 2014, telephone follow-up for those with negative screening results only identified a boy with facial abnormalities and developmental delay, which was similar to his older sister, combined karyotyping and fluorescence in situ hybridization analysis has verified the karyotype of the boy as 46,XY,rec(14)dup(14q)inv(14)(p12q14)pat., Conclusion: Our results indicated that sequencing of plasma free DNA can rapidly detect fetal chromosomal aneuploidies. The method is non-invasive, and the results are highly consistent with karyotype analysis in terms of accuracy and specificity. Non-invasive testing can be used as an effective adjunct to conventional prenatal diagnostic methods, which can greatly reduce unnecessary invasive prenatal diagnosis. However, the sensitivity and accuracy for aneuploidy detection other than chromosome 13/18/21 still need to be improved.

Objective: To explore the genetic etiology for fetuses with increased nuchal translucency (NT) but a normal karyotype at whole genome level by chromosome microarray analysis (CMA)., Methods: Seventy-eight fetuses with increased NT (≥ 3.0 mm) but a normal karyotype were collected between 11(+0) and 13(+6) gestational weeks. Genomic DNA was extracted, and microarray testing was performed using Affymetrix CytoScan(TM) HD arrays. The data was analyzed by CHAS software. All detected copy number variations (CNVs) were confirmed with real-time quantitative polymerase chain reaction., Results: The CMA assay has detected pathogenic CNVs in 6 fetuses (7.69%), which have ranged from 0.41 Mb to 15.87 Mb. Well-known microdeletion or microduplication syndromes including Wolf-Hirschhorn syndrome, 22q11 microdeletion syndrome and ATR-16 syndrome were identified in three cases. The detection rates in fetuses with or without structural abnormalities were 18.18% and 5.97%, respectively (P=0.198 with Fisher's Exact Test). The average NT in fetuses with pathogenic CNVs and non-pathogenic CNVs has measured 4.48 mm and 4.22 mm (P=0.735 by Mann-Whitney Test)., Conclusion: For fetuses with increased NT, CMA can identify chromosomal microdeletion/microduplication unrecognizable by conventional karyotyping analysis. It may therefore play an important role in prenatal diagnosis and genetic counseling by improving the diagnostic rate.

Objective: To optimize the methods for genetic detection and prenatal diagnosis of Duchenne muscular dystrophy (DMD)., Methods: Denaturing high-performance liquid chromatography (DHPLC), multiplex PCR (mPCR), sequencing and other molecular techniques were used in combination for molecular diagnosis of 8 cases diagnosed as DMD., Results: Among the 8 cases, 4 have carried large deletions, 3 have point mutations, among which 6 were of de novo type. Prenatal diagnosis were offered for 5 families, the results showed that none of the fetuses had carried large deletions or point mutations. The pregnancies had continued and healthy babies were born., Conclusion: Combined use of short tandem repeat, DHPLC, mPCR and sequencing can improve the detection of DMD gene mutations. By establishing and optimizing genetic and prenatal diagnostic methods, accurate genetic counseling can be provided for families affected with DMD.

Objective: To determine the karyotype of a fetus with transverse aortic arch hypoplasia, and to investigate the feasibility of array-based comparative genomic hybridization (array-CGH) for molecular genetic diagnosis., Methods: G-banding was performed to analyze the karyotypes of the fetus and its parents, and array-CGH was applied to identify the chromosomal abnormality of the fetus., Results: G-banding analysis revealed that the pregnant woman has carried a balanced translocation 46,XX, t(8;16)(p21;q24), while the fetus has carried an unbalanced translocation 46,XX,der(16)t(8;16)(p21;q24)mat. Array-CGH analysis suggested that the derivative chromosomal fragment has originated from 8p with breakpoints in 8p23.3-p21.3., Conclusion: Trisomy 8p23.3-p21.3 may have predisposed to transverse aortic arch hypoplasia in the fetus. Parental karyotype analysis could help to characterize the translocation and evaluate the recurrent risk. Compared with routine karyotype analysis, aCGH has a higher resolution and greater accuracy for mapping chromosomal aberrations.

Objective: Diagnosis and prenatal diagnosis to a family of hemoglobin variant with α-thalassemia., Methods: Whole blood cell analysis, hemoglobin analysis by capillary zone electrophoresis (CZE), Gap-PCR, polymerase chain reaction-reverse dot blot (PCR-RDB) assay and DNA sequencing., Results: Hb Zurich Albisrieden with α°-thalassemia lead to severe anemia. The genotype of fetus is also Hb Zurich Albisrieden with α°-thalassemia., Conclusion: Abnormal hemoglobin with α-thalassemia may lead to severe anemia, Prenatal diagnosis of thalassemia has the vital significance for eugenic birth.

Objective: To analyze 81 spontaneous abortion samples with fluorescence in situ hybridization (FISH)., Methods: Chromosome 13, 21, 16, 22, 18, X and Y probes were used to detect the samples., Results: FISH was successful in 80 cases (98.77%). Among these, 35 (43.75%) had an abnormal karyotype, which included 19 autosomal aneuploidies, 6 sex chromosome aneuploidies, 9 triploidies and 1 tetraploidy., Conclusion: FISH is a rapid and easy method for detecting chromosomal aneuploidies in spontaneous abortion samples, and has a higher detection rate in early spontaneous abortion samples.

Objective: To analyze the deletion region for two fetal cases with large Yq deletions in order to provide genetic counseling and prenatal diagnosis., Methods: For both cases, amniotic fluid samples were cultured and analyzed with G banding and fluorescence in situ hybridization (FISH). Multiplex polymerase chain reaction was also carried out to amplify 15 sequence tagged sites (STS) of azoospermia factor (AZF) on the Y chromosome., Results: For both samples, the karyotypes were determined as 46,X,del(Y)(pter→q11:). No heterochromatin was found in C band. The karyotypes of their fathers were 46,XY, and heterochromatin was found in C band. STS analyses suggested that only sY82, sY84 and sY86 in AZFa were amplifiable while the other 12 STS were negative in amniotic fluid for the first case, which indicated deletions of AZFb, AZFd and AZFc. No AZF deletion was found in its father. For the second case, all 15 STS were amplifiable in the amniotic fluid, suggesting no AZF deletion. No AZF deletion was found in its father too., Conclusion: Conventional karyotyping combined with FISH and molecular genetics techniques can enable characterization of AZF microdeletions and facilitate genetic counseling and prenatal diagnosis.