Great efforts have been made in the prenatal screening and prenatal diagnosis of aneuploidy in China.Nevertheless,the coverage percentage of screening is still low,and the capability of diagnosis is far from enough.To elevate the efficacy of prenatal screening,developing fast aneuploidy diagnositic techniques is quite important.Cell-free DNA testing is believed to be a confirmatory screening test of aneuploidy.Fluorescence in situ hybridization,fluorescence quantitative PCR might be used in the prenatal diagnosis in high risk women.Chromosomal microarray analysis has high sensitivity in the diagnosis of microdeletion and microduplication.The era of cytomolecular diagnosis is coming.

Objective To calculate the incidence of chromosomal abnormalities at second trimester in women who were 35 or older at their expected date of birth.Methods The amniocentesis and karyotyping results in Peking Union Medical College Hospital from January 1st,2001 to June 30th,2011 were retrospectively analyzed.The only indication for amniocentesis in these group of woman was advanced maternal age.A total of 6584 cases Were included in this study and were divided into two groups according to maternal age,ie.35-39 and ≥40 year old group.The incidences of fetal 47,+ 21,47,+ 18 and sex aneuploidies were calculated and compared between two groups by Chi-square test.Results Altogether,121 cases were diagnosed to be abnormal chromosome,and the overall incidence was 18.38‰ (121/6584).The abnormal karyotypes included 111 cases of aneuploidies (mosaicism included) and 10 cases of structural abnormalities.The aneuploidies included 59 cases of 47,+21 (8.96‰,59/6584),25 cases of 47,+18 (3.80‰,25/6584),2 cases of 47,+13 (0.30‰,2/6584) and 25 cases of sex aneuploidies (3.80‰,25/6584).Fetal 47,+21 was the most frequent chromosomal abnormality,accounting for 53.15％ (59/111) of all aneuploidies.The incidence of fetal 47,+21 was significantly higher in ≥40 year-old group than that of 35-39 year old group[13.99‰(16/1144) vs 7.90‰(43/5440),x2=3.937,P=0.047].There were no statistical differences of the incidences of fetal 47,+ 18 and sex aneuploidies between the two groups.Conclusions The main fetal chromosomal abnormalities in women aged 35 and older are the aneuploidies of chromosome 21,18,13 and sex chromosomes.The incidence of fetal 47,+21 is significantly increased in the women aged 40 years and older.So prenatal screening should be provided first to women at 35-39 years of age and amniocentesis should be the first choice of prenatal diagnosis for women over 40 years old.

Objective To evaluate the residual risk (i.e.failure risk in detecting aneuploidies abnormalities except for chromosome 13,18,21,X and Y) of cytogenetic abnormalities using interphase fluorescence in situ hybridization (FISH) for the second-trimester amniocytes.Methods The results of interphase FISH and conventional karyotyping of 2 837 consecutive amniotic fluid specimens were analyzed retrospectively.Probes for chromosomes 13,18,21,X and Y were used.The detection rate and residual risk for interphase FISH were calculated for the following three major clinical indications for prenatal diagnosis (advanced maternal age,abnormal maternal serum screening indicating an increased risk for trisomy 18 or trisomy 21,and ultrasound abnormalities).Results Consecutive interphase FISH and karyotyping of second-trimester amniocytes for prenatal diagnosis were performed from January 1,2010 to July 31,2013.Among the 2 837 cases,85 (3.0％) cases with abnormal karyotypes were found,including 73 cases of aneuploidies involving chromosome 13,18,21,X and Y,which were considered detectable by interphase FISH; 12 cases of chromosomal anomalies,other than aneuploidies of chromosome 13,18,21,X and Y,were diagnosed after karyotyping and were not detected by interphase FISH,including six cases of balanced rearrangements,five cases of imbalanced rearrangements,and one case of pseudomosaic of trisomy 20.Of these 12 chromosomal anomalies,three cases of imbalanced rearrangements involving chromosome 21 showed positive FISH results,and the other nine cases showed negative FISH results among which four case of hereditary balanced rearrangemerts and two cases of novel balanced rearrangements.The total detection rate for interphase FISH was 89.4％ (76/85),the misdiagnosis rate of chromosome abnormalities was 14.1％(12/85),and the residual risk was 0.43％ (12/2 761) following interphase FISH of the second-trimester amniocytes.Conclusions Interphase FISH is a useful adjunct to conventional karyotyping,but should not be regarded as a replacement for karyotyping as too many structural chromosomal abnormalities will be missed.Providing patients with a detection rate and residual risk during counselling may help them understand the advantages and limitations of interphase FISH in their prenatal diagnostic evaluation.

Objective To evaluate the efficacy and safety of pelvic arterial embolization (PAE) in women with intractable primary postpartum hemorrhage (PPH). Methods Clinical data of 36 cases were analyzed retrospectively in which women underwent PAE for intractable primary PPH in Peking Union Medical College Hospital between Jan 2006 and Jan 2015. The success rate of PAE were measured and possible predictive risk factors associated with treatment failure were analyzed. The complications secondary to PAE were also recorded. Results (1)The etiology of PPH. Among the 36 cases, 21 patients delivered viginally (Group VD) and 15 received cesarean section (Group CS). The most frequent cause of PPH was uterine atony (72%, 26/36). The less common causes were placental problems (28%, 10/36), genital tract trauma (6%, 2/36) and coagulation defects (3%, 1/36) in turn. Three patients (8%, 3/36) had combined causes.(2)Interventions before PAE. Uterotonic medications were used in all patients. 31 patients received carboprost methylate suppositorites,27 received carbetocin and 31 received carboprost tromethamine. Besides, 20 patients received one or more surgical interventions before PAE. PAE was performed when these interventions failed. (3) Characteristics of PAE. Altogether 78 arteries were embolized in 36 cases. Embolization of bilateral uterine arteries was performed in 31 cases, right internal iliac artery and bilateral inferior epigastric arteries were embolized in one case. Right internal pudendal artery, bilateral uterine arteries and bilateral internal iliac arteries were embolized in one case. And bilateral uterine arteries, bilateral internal iliac arteries were embolized in one case. In the other 2 cases, bilateral internal iliac arteries were embolized.(4)Efficacy of PAE. The overall technical success rate of PAE was 100%(36/36), while the clinical success rate was 94%(34/36). All patients survived.(5)Complications of PAE. 15 patients were transferred to ICU after PAE for 1 to 7 days. Except self-limited fever, no puncture site hematoma, buttock necrosis or vessel rupture was observed. The effect on menstrual cycle and fertility were followed in 25 patients. 17 (68%, 17/25) reported resumption of normal menses and 8 (32%, 8/25) reported amenorrhea. Three pregnancies after PAE were observed. Conclusion PAE is a safe and effective treatment for intractable primary PPH which can prevent hysterectomy and preserve fertility of patients.

[Abstrcat] Objectives To analyze 3 cases of 17q12 microdeletion syndrome diagnosed prenatally, and to demonstrate clinical phenotype of the syndrome in prenatal setting.Methods From January 2013 to July 2017,1 370 women received invasive prenatal diagnosis and chromosome microarray analysis(CMA)in Peking Union Medical College Hospital. Among them, 3 fetuses were diagnosed as 17q12 microdeletion syndrome.All 3 cases were low-risk pregnancies.Abnormal structures in fetal kidney were found in all 3 cases, including 1 case of multiple renal cysts,2 cases of bilateral hyperechogenic kidneys.These women accepted invasive prenatal diagnosis followed by karyotyping, parental fluorescence in situ hybridization or CMA validation.Results The second and third trimester ultrasound showed that all 3 fetuses had bilateral renal structural abnormalities, including hyperechogenic kidney, multiple cysts and renal pelvis dilatation. The karyotyping of the 3 fetuses were normal.CMA examination showed that each case had 1.4-1.6 Mb deletion in 17q12 region.Two cases were de novo deletion and 1 case was inherited from the mother who had mild symptoms. The 3 women decided to terminate pregnancies after genetic counseling. Conclusion 17q12 microdeletion syndrome is a recurrent chromosome microdeletion syndrome, and the unique phenotype in prenatal setting is the abnormal structure of bilateral kidneys.A few cases of 17q12 microdeletion syndrome even inherited normally phenotypical parents, and prenatal genetic counseling of 17q12 microdeletion syndrome is relatively difficult.

OBJECTIVE: To carry out genetic analysis for a fetus with confined placental mosaicism (CPM) for trisomy 2 (T2) in conjunct with fetal uniparental disomy (UPD). METHODS: Amniocentesis and chromosomal karyotyping was carried out for a pregnant woman with a high risk for chromosome 2 anomalies indicated by non-invasive prenatal testing (NIPT). Single nucleotide polymorphism array (SNP-array) and trio-whole exome sequencing (Trio-WES) were carried out. Ultrasonography was used to closely monitor the fetal growth. Multifocal sampling of the placenta was performed after delivery for copy number variation sequencing (CNV-seq). RESULTS: The fetus was found to have a normal chromosomal karyotype. SNP-array has revealed multiple regions with loss of heterozygosity (LOH) on chromosome 2. Trio-WES confirmed the presence of maternal UPD for chromosome 2. Ultrasonography has revealed intrauterine growth restriction and oligohydramnios. Intrauterine fetal demise had occurred at 23⁺⁴ weeks of gestation. Pathological examination had failed to find salient visceral abnormality. The placenta was proved to contain complete T2 by CNV-seq. CONCLUSION T2 CPM can cause false positive result for NIPT and may be complicated with fetal UPD, leading to adverse obstetric outcomes such as intrauterine growth restriction, oligohydramnios and intrauterine fetal demise.
Female ; Humans ; Pregnancy ; Amniocentesis ; Chromosomes, Human, Pair 2/genetics* ; DNA Copy Number Variations ; Fetal Death ; Fetal Growth Retardation/genetics* ; Fetus ; Mosaicism ; Oligohydramnios ; Placenta ; Trisomy/genetics* ; Uniparental Disomy/genetics*

Objective To investigate the prenatal diagnosis and genetic counseling of fetal nuchal fold (NF) thickening.Methods This study retrospectively analyzed 17 fetuses with increased NF detected by prenatal ultrasound examination in Peking Union Medical College Hospital,Peking Union Medical College & Chinese Academy of Medical Sciences from December 1,2016 to December 1,2017.All cases were divided into isolated (isolated group) or non-isolated increased NF group (non-isolated group) according to whether the fetus had concomitant ultrasonographic abnormalities or not.Karyotype and chromosomal microarray analysis (CMA) were performed on all cases.Clinical data,prenatal genetic testing results and pregnancy outcomes were analyzed.Results Of those twelve cases in the isolated group,two were terminated due to the identification of chromosomal abnormalities and pathogenic copy number variations (CNVs) and the fetal autopsy results were consistent with the prenatal diagnosis.The rest 10 pregnancies were all continued including one fetus carrying a variant of unknown significance,which was proved to be a paternal heredity by CMA,and nine without genetic abnormalities and all-these infants were healthy during follow-up.Among the five non-isolated cases,one was diagnosed as trisomy 21 by karyotyping and CMA,and the other four were found to have structural abnormalities under ultrasound scan,but without genetic abnormalities in karyotyping and CMA.And all the five pregnancies were terminated after genetic counseling and three of them chose whole exome sequencing (WES) for further test.One homozygous mutation in CHRNA 1 gene and one de novo mutation in SETD2 gene were found in two cases,respectively,while no abnormality was identified in the other one case.Conclusions Once increased NF were indicated by ultrasound examination,prenatal genetic testing should be offered to the patients,including CMA,regardless of other ultrasonographic abnormalities,and WES should also be offered when necessary.Considering a thickened NF is associated with increased risks of structural defects,a close follow-up with fetal echocardiography and ultrasound is required even the prenatal tests are normal.

Objective: To investigate the impact of maternal X chromosome aneuploidies on cell free DNA (cf-DNA) prenatal screening. Methods: After genetic counseling, invasive prenatal diagnosis was provided for the 124 cases with high risk of sex chromosome aneuploidie (SCA) indicated by cf-DNA prenatal screening. For cases with discordant results of fetal prenatal diagnosis and cf-DNA prenatal screening, maternal leukocyte was collected for copy number variation sequencing (CNV-seq) to detect whether the maternal X chromosome was carrying variations. Results: Totally, 124 cases with high risks of SCA indicated by cf-DNA prenatal screening, 9 cases refused to take invasive prenatal diagnosis, while the remaining 115 cases received. Among the 115 cases, 41 cases received accordant results with cf-DNA prenatal screening while 74 cases discordant. Among the 74 cases with discordant results, 19 cases were indicated with maternal X chromosome variations by maternal leukocyte CNV-seq, which accounting for 25.7% (19/74) of the SCA false positive cases, and 15.3% (19/124) of all SCA cases. Conclusions Pregnant women with X chromosome variations may affect the results of cf-DNA prenatal screening, resulting in false positive or false negative outcomes, it should be emphasized that the cf-DNA results may be affected by maternal X chromosome variations. In cases with discordant results of prenatal diagnosis and cf-DNA prenatal screening, maternal leukocyte CNV-seq is recommended to find the reasons of false positive or negative results. And cf-DNA prenatal screening is not recommended for pregnant women who are already known with X chromosome variations.

Genome editing tools such as the clustered regularly interspaced short palindromic repeat (CRISPR)-associated system (Cas) have been widely used to modify genes in model systems including animal zygotes and human cells, and hold tremendous promise for both basic research and clinical applications. To date, a serious knowledge gap remains in our understanding of DNA repair mechanisms in human early embryos, and in the efficiency and potential off-target effects of using technologies such as CRISPR/Cas9 in human pre-implantation embryos. In this report, we used tripronuclear (3PN) zygotes to further investigate CRISPR/Cas9-mediated gene editing in human cells. We found that CRISPR/Cas9 could effectively cleave the endogenous β-globin gene (HBB). However, the efficiency of homologous recombination directed repair (HDR) of HBB was low and the edited embryos were mosaic. Off-target cleavage was also apparent in these 3PN zygotes as revealed by the T7E1 assay and whole-exome sequencing. Furthermore, the endogenous delta-globin gene (HBD), which is homologous to HBB, competed with exogenous donor oligos to act as the repair template, leading to untoward mutations. Our data also indicated that repair of the HBB locus in these embryos occurred preferentially through the non-crossover HDR pathway. Taken together, our work highlights the pressing need to further improve the fidelity and specificity of the CRISPR/Cas9 platform, a prerequisite for any clinical applications of CRSIPR/Cas9-mediated editing.
Blastocyst ; CRISPR-Cas Systems ; Hemoglobins, Abnormal ; genetics ; metabolism ; Humans ; Zygote

β-Thalassemia is a global health issue, caused by mutations in the HBB gene. Among these mutations, HBB -28 (A>G) mutations is one of the three most common mutations in China and Southeast Asia patients with β-thalassemia. Correcting this mutation in human embryos may prevent the disease being passed onto future generations and cure anemia. Here we report the first study using base editor (BE) system to correct disease mutant in human embryos. Firstly, we produced a 293T cell line with an exogenous HBB -28 (A>G) mutant fragment for gRNAs and targeting efficiency evaluation. Then we collected primary skin fibroblast cells from a β-thalassemia patient with HBB -28 (A>G) homozygous mutation. Data showed that base editor could precisely correct HBB -28 (A>G) mutation in the patient's primary cells. To model homozygous mutation disease embryos, we constructed nuclear transfer embryos by fusing the lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes. Notably, the gene correction efficiency was over 23.0% in these embryos by base editor. Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%. In addition, we found that base editor variants, with narrowed deamination window, could promote G-to-A conversion at HBB -28 site precisely in human embryos. Collectively, this study demonstrated the feasibility of curing genetic disease in human somatic cells and embryos by base editor system.
APOBEC-1 Deaminase ; genetics ; metabolism ; Base Sequence ; Blastomeres ; cytology ; metabolism ; CRISPR-Cas Systems ; Embryo, Mammalian ; metabolism ; pathology ; Female ; Fibroblasts ; metabolism ; pathology ; Gene Editing ; methods ; Gene Expression ; HEK293 Cells ; Heterozygote ; Homozygote ; Humans ; Point Mutation ; Primary Cell Culture ; Promoter Regions, Genetic ; Sequence Analysis, DNA ; beta-Globins ; genetics ; metabolism ; beta-Thalassemia ; genetics ; metabolism ; pathology ; therapy