Comparison of the etiological constitution of two and three or more recurrent miscarriage / 中华妇产科杂志

Objective To compare the etiological constitution of recurrent miscarriage (RM) between patients with consecutive two and three or more miscarriages through combining the routine examination results and embryonic karyotype. Methods Patients with a history of two or more consecutive clinical miscarriages(≤12 weeks of gestation)consulting in the RM clinic of the First Affiliated Hospital of Sun Yat-sen University from March 2011 to January 2016 were collected. Six hundred and ninety-six with detailed history recorded, routine clinical examinations of RM and at least once embryonic karyotype were ultimately enrolled in this study. Their etiological constitution of RM were analyzed in groups of consecutive two and three or more miscarriage. The etiologies of RM in analysis consisted of women age, body mass index (BMI), chromosome abnormalities of couples, uterine abnormalities, endocrinology abnormalities and antiphospholipid syndrome(APS). Results (1)Among 696 patients, the abnormal embryonic karyotypes was 60.6%(422/696)and routine RM etiologies was 32.2%(224/696), leaving the ratio of unexplained RM was only 29.0%(202/696).(2)A total of 717 embryo karyotype were found in 696 patients, included 21 cases with twice embryo karyotype results the percentage of normal embryo was 39.7%(285/717), while abnormal ones was 60.3%(432/717). Among the types of abnormal karyotype, the most common ones (>10%)were trisomy 16(19.2%, 83/432), monosome X(11.3%, 49/432)and trisomy 22(10.9%, 47/432). (3)Among the 696 RM patients, the number of two and three or more miscarriages were respectively 446(64.1%,446/696)and 250(35.9%,250/696). Comparing groups of three or more miscarriages with two miscarriages, there were significant differencein older age as well as uterine adhesion(P<0.05). But no difference was found in body mass index(BMI), the rates of chromosome abnormalities of couples, uterine abnormalities except uterine adhesion, endocrinology abnormalities and APS (all P>0.05) between two groups. Conclusions The abnormal embryonic karyotype is the most common cause of first-trimester RM. The etiological constitution of two and three or more recurrent miscarriages is accordant, suggesting that routine clinical examination and the embryonic karyotype should be started following two consecutive clinical early miscarriages.

Correction of β-thalassemia mutant by base editor in human embryos

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.

Spontaneous ovulation in in vitro fertilization-embryo transfer cycles using gonadotropin-releasing hormone antagonist：a large-sample retrospective study / 中华妇产科杂志

Objective To investigate the premature spontaneous ovulation rates in in vitro fertilization-embryo transfer (IVF-ET) cycles using gonadotropin-releasing hormone antagonist (GnRH-ant) and gonadotropin-releasing hormone agonist (GnRH-a), as well as the risk factors for premature spontaneous ovulation. Methods The rates of premature spontaneous ovulation in a total of 10 612 cycles using GnRH-ant or GnRH-a were compared. Matched case-controlled study and binary logistic regression model were conducted to analyze the risk factors for premature spontaneous ovulation. Results The spontaneous ovulation rate in the whole for GnRH-a cycles was 0.15%(13/8 514), compared with a 1.62%(34/2 098) in GnRH-ant cycles (P<0.01). Further matched controlled study and regression analyze found out that higher basal FSH level was a predominant risk and prediction factor for spontaneous ovulation (OR=1.20, P=0.009). Conclusions In GnRH-ant cycles, spontaneous ovulation rate is about 10 times than which in GnRH-a cycles. Diminished ovarian function is a predominate risk factor for premature spontaneous ovulation.

Clinical analysis of preimplantation genetic diagnosis with HLA matching for beta-thalassemia / 中华妇产科杂志

Objective To investigate the efficacy and feasibility of preimplantation genetic diagnosis (PGD) with human leukocyte antigen (HLA) matching for beta-thalassemia. Methods A total of 43 referred beta-thalassemia couples, with at least on child in need of hematopoietic stem cell transplantation (HSCT), underwent PGD for HLA matching at the First Affiliated Hospital of Sun Yat-sen University from 2010 to 2015. PGD cycles of these couples were retrospectively analyzed, and 15 infants born from PGD-HLA were followed up. Results A total of 84 oocyte retrieval cycles were performed, providing 14±7 oocytes per cycle. Fifty nine embryos biopsied cycles were done, including 24 cleavage stage and 35 blastocyst stage biopsy cycles. In cleavage stage, 259 embryos were biopsied, 93.4% (242/259) of them with conclusive molecular diagnosis, and the percentage of unaffected embryos (normo-homozygote and heterozygote) was 71.4%(185/259). The percentage of HLA matched unaffected embryos was 9.3%(24/259). In blastocyst stage, 306 embryos were biopsied, while 93.8% (287/306) of them were conclusive, and the percentage of unaffected embryos was 70.6% (216/306). The percentage of HLA matched unaffected embryos in blastocyst stage biopsy was 14.4%(44/306), which was higher than in cleavage stage biopsy (P<0.05). Forty three female carriers underwent 48 embryo transfer cycles including 3 fresh and 45 frozen-thawed embryo transfer cycles. Three fresh embryo transfer cycles were done after cleavage stage biopsy, resulted in a birth of healthy twins born at 36 weeks′gestation. All the embryos were frozen after blastocyst biopsied. Totally, 54 frozen-thawed embryos that were transferred in 45 frozen-thawed embryo transfer cycles included 25 embryo from cleavage stage biopsy and 29 embryo from blastocyst stage biopsy, and 42 of them were HLA matched. Clinical pregnancy rate and implantation rate per cycle in frozen-thawed embryo transfer were 38%(17/45) and 37%(20/54) respectively. A total of 15 infants were born, 2 were from a fresh embryo transfer cycle, and 13 were from frozen-thawed embryo transfer cycles. Results of prenatal diagnosis from delivered cases were matched to that of PGD. Four sick children have been cured by HSCT from these HLA matched born siblings. Conclusion PGD with HLA matching is an established method for conceiving a child who may donate hematopoietic stem cells to save an ill sibling.

Preimplantation genetic diagnosis for carriers of thalassemia and chromosomal abnormality / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide preimplantation genetic diagnosis(PGD) for two couples carrying thalassemia mutations and chromosomal abnormalities.</p><p><b>METHODS</b>Couple 1 were both carriers of β 41/42 thalassemia mutations, while the husband has carried a reciprocal translocation with a karyotype of 46,XY,inv(9)(p11;q13),t(11;22)(q25;q13). Couple 2 were both carriers of α (-SEA) thalassemia mutation. Their chromosome karyotypes were both normal, but had two spontaneous abortions. The couples had received 1 and 3 blastocysts respectively through in vitro fertilization(IVF) cycles. Following the biopsy, the cells underwent whole genome amplification, and the amplified DNA from each embryo was subjected to genetic testing and a 23-chromosome single nucleotide polymorphism(SNP) microarray assay.</p><p><b>RESULTS</b>The embryo of couple 1 was diagnosed as carrier of β 41/42 thalassemia with euploid chromosomes. The embryo was transferred and resulted in intrauterine pregnancy. Similarly, an embryo of couple 2 was verified as carrier of α (-SEA) thalassemia with euploid chromosomes.</p><p><b>CONCLUSION</b>PGD for aneuploidy coupled with testing for single gene disorders via trophectoderm biopsy and whole genome amplification is feasible. The approach can attain diagnosis with minimal damage with sound clinical outcome.</p>

Preimplantation genetic diagnosis of infantile malignant osteopetrosis in a Chinese family / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the application of preimplantation genetic diagnosis (PGD) for infantile malignant osteopetrosis (IMO).</p><p><b>METHODS</b>For a family affected with IMO, PGD was provided using combined parental mutation detection and haplotype constructions with microsatellite markers spanning the TCIRG1 gene. Prenatal diagnosis was performed on the chorionic villus and amniocentesis samples by direct sequencing.</p><p><b>RESULTS</b>Prenatal diagnosis showed that the fetus by the third pregnancy has carried the parental mutations [c.242delC (p.Pro81Argfs*85) and c.1114C>T (p.Gln372*)], and the pregnancy was terminated. PGD was subsequently performed through mutations detection and haplotype analyses following whole genome amplification (WGA) of each of 13 cells. The results showed that 6 of the 13 embryos were unaffected, 3 were carriers and 4 were affected. Well developed unaffected/carrier embryos were selected and transferred into the uterus. A single pregnancy was confirmed. Subsequently pre- and post-natal diagnoses have confirmed development of a healthy child.</p><p><b>CONCLUSION</b>The study demonstrated the advantage of PGD over prenatal diagnosis when natural pregnancies have repeatedly produced IMO children/fetuses.</p>

CRISPR/Cas9-mediated gene editing in human tripronuclear zygotes

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.

Clinical investigation to compare aCGH and FISH in preimplantationgenetic diagnosis of chromosome translocation carriers / 中华妇产科杂志

Objective To investigate the clinical use of array comparative genomic hybridization (aCGH) with fluorescence in situ hybridization (FISH) in preimplantion genetic diagnosis (PGD)for reciprocal and Robertsonian translocation carriers.Methods From Jan.2012 to Jun.2013,a total of 220 PGD cycles from 151 reciprocal translocation and 62 Robertsonian translocation carrier couples,including 33 cycles for reciprocal translocation carriers and 22 cycles for Robertsonian translocation carriers performed using array CGH,and 119 cycles for reciprocal translocation carriers and 46 cycles for Robertsonian translocation carriers performed using FISH were retrospectively studied.The rate of accurate diagnosis was compared between two methods.Results Normal and/or balance rates of the two translocated chromosomes detected by aCGH for both reciprocal and Robertsonian translocation carriers were 38.20％ (123/322) and 67.20％ (127/189),significantly higher than 15.39％ (195/1 267) and 30.75％ (202/657) by FISH (all P ＜0.05).Abnormal rates of the two translocated chromosomes detected by aCGH for both reciprocal and Robertsonian translocation carriers were 59.32％ (191/322) and 30.69％ (58/189),significantly lower than 83.03％ (1 052/1 267) and 67.43％ (443/657) by FISH (all P ＜ 0.05).And the rate of aneu ploidy in non-translocated chromosome from reciprocal translocation embryos was 20.19％ (65/322),which was significantly lower than 38.62％ (13/189) from Robertsonian translocation embryos (P ＜ 0.01).Conclusions Normal and/or balance rates of the two translocated chromosomes detected by array CGH were significantly higher than FISH.And the rate of aneuploidy in non-translocated chromosomes from reciprocal translocation embryos was significantly lower than that from Robertsonian translocation embryos.

A preliminary study on the application of array comparative genomic hybridization for preimplantaion genetic diagnosis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the value of array comparative genomic hybridization (array CGH) technique for preimplantation genetic diagnosis (PGD).</p><p><b>METHODS</b>Array CGH was performed on three types of cells, which included 3-5 cells isolated from B2/C38/A1 embryonic stem cell lines, single cells isolated from two discarded normal fertilized embryos, and 10 blastocysts biopsied from 5 couples undergoing PGD for chromosomal translocations. For the 10 blastocysts, 8 were abnormal embryos, 1 appeared to be normal but showed arrested development, and 1 embryo was without any fluorescence signals. 24sure V3 or 24sure+ array chips were applied for CGH analysis. The results were analyzed with a BlueFuse Multi software.</p><p><b>RESULTS</b>(1) The results of cells from B2/C3/A1 embryo stem cells by array CGH were consistent with karyotyping analysis. (2) For the 6 single cell samples from two discarded embryos, 2 blastomeres from one embryo were diagnosed as with aneuploidy and a normal karyotype, respectively. Two out of 4 blastomeres biopsied from another embryo were normal, whilst the remaining two were diagnosed with aneuploidies of -22 and +13. Repeated detection with 24sure+ array was consistent with the 24sure V3 result. (3) Ten cell masses from 10 embryos in PGD cycles were successfully analyzed with array CGH, among which four were confirmed with fluorescence in situ hybridization (FISH) on day 3. In two of them, array CGH confirmed FISH diagnosis. For the remaining two, additional aneuploidies for chromosomes not tested by FISH were discovered by array CGH. Another embryo diagnosed as no signal by FISH was found to have trisomy 13 by array CGH. The remaining 5 embryos also showed discordant results by FISH and array CGH. One embryo from a Robertsonian translocation carrier was found to have monosomy 13 by FISH but trisomy 14 and additional aneuploidies by both 24sure V3 and 24sure+ chips. One embryo with many fragments and arrested development by D5 showed discordant results by FISH and array CGH. However, the FISH and array CGH results for other two embryos from this reciprocal translocation carrier were consistent. Three embryos with inconsistent results by FISH and array CGH had a chromosomal translocation involving q11 region.</p><p><b>CONCLUSION</b>Array CGH is useful for PGD applications for its capability to detect structural chromosomal abnormalities through screening of aneuploidies. However, the 24sure V3 array may not suit detection of translocations with breakpoints close to the q11 region of chromosomes.</p>

Clinical analysis of 100 preimplantation genetic diagnosis cycles / 中华妇产科杂志

Objective To investigate influence of chromosomal translocations on early embryo development and to evaluate the efficacy and feasibility of preimplantation genetic diagnosis (PGD)techniques through clinical analysis on PGD cycles. Methods Embryo development, efficacy of PGD and clinical outcome of 100 cycles were studied retrospectively, including 23 cycles with Robertsonian translocations, 19 cycles with reciprocal translocations, and 58 cycles for α-Thalassaemia. Results Among 354 embryos biopsied by PGD for translocations, 321 (90. 7% ) presented fluorescence in situ hybridization (FISH) results. The rate of normal/balanced embryos in the Robertsonian translocation was 38. 3% (64/167),which was significantly higher than 20. 8% (32/154) in the reciprocal translocation group. Amplification was achieved in 443 blastomeres from 537 embryos in Thalassaemia group, which given to an amplification efficiency rate of 82. 5% ( 443/537 ). Totally, 140 normal homozygous, 112 heterozygotes and 155 affected homozygous embryos were identified, while 36 embryos had uncertain result. The successful diagnostic rate was 75.8% (407/537). After 3 days in the translocation groups, the rate of normal and/or balanced translocations in biopsed embryos with ≥7 cells was 34. 4% (77/224), which was significantly higher than 19. 6% ( 19/97 ) of biopsed embryos with ＜ 7 cells. After 4 days, the compaction rate in normal/balanced embryos was 59.4% ( 57/96 ), which was significantly higher than 34. 2% ( 77/225 ) in imbalanced embryos significantly. Seventy-five embryos transferred in 37 cycles with translocations group led to clinical pregnancy rate of 27.0% (10/37), and 170 embryos transferred in 58 cycles with Thalassaemia got a clinical pregnancy rate of 43. 1% ( 25/58 ) . Conclusions PGD can provide management efficiently for both chromosome translocations and Thalassaemia. Translocations might have slightly negative impact on embryo development before implantation.