OBJECTIVE: To carry out preimplantation genetic testing for monogenic/single gene disorders (PGT-M) for a Chinese family affected with Molybdenum co-factor deficiency due to pathogenic variant of MOCS2 gene. METHODS: A family with molybdenum co-factor deficiency who attended to the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region in April 2020 was selected as the research subject. Trophoblast cells were biopsied from blastocysts fertilized by intracytoplasmic sperm injection. Embryos carrying the MOCS2 gene variant and chromosome copy number variation (CNV) of more than 4 Mb were detected by single-cell whole genome amplification, high-throughput sequencing and single nucleotide polymorphism typing. Embryos without or carrying the heterozygous variant and without abnormal chromosome CNV were transplanted. During mid-pregnancy, amniotic fluid sample was collected for prenatal diagnosis to verify the results of PGT-M. RESULTS: Eleven oocytes were obtained, among which three blastocysts were formed through culturing. Results of genetic testing suggested that one embryo was heterozygous for the maternally derived MOCS2 gene variant and without chromosomal CNV. Following embryo transfer, intrauterine singleton pregnancy was attained. Prenatal diagnosis by amniocentesis at 18 weeks of gestation revealed that the MOCS2 gene variant and chromosomal analysis results were both consistent with that of PGT-M, and a healthy male infant was born at 37⁺⁵ weeks of gestation. CONCLUSION PGT-M has helped the couple carrying the MOCS2 gene variant to have a healthy offspring, and may become an important method for couples carrying other pathogenic genetic variants.
Female ; Humans ; Pregnancy ; Aneuploidy ; China ; DNA Copy Number Variations ; Genetic Testing/methods* ; Preimplantation Diagnosis/methods* ; Metal Metabolism, Inborn Errors/genetics*

Chromosomal mosaicism (CM) is a common phenomenon in preimplantation genetic testing (PGT). In embryos with CM, genetic contents of trophoblastic ectodermal (TE) cells may be different from that of the inner cell mass (ICM) which will develop into the fetus. Embryos with low mosaic proportion could give rise to healthy live births after transplantation, but are accompanied with high pregnancy risks such as high abortion rate. In order to provide a more comprehensive understanding for CM embryos, this article has systematically summarized the recent progress of research on the definition, mechanism, classification, PGT techniques, self-correction mechanism, transplantation outcome and treatment principles for CM embryos.
Pregnancy ; Female ; Humans ; Preimplantation Diagnosis/methods* ; Mosaicism ; Aneuploidy ; Genetic Testing/methods* ; Blastocyst

OBJECTIVE: To explore the influence of gender of chromosomal translocation carriers on the occurrence of embryonic chromosomal aberrations. METHODS: A retrospective study was carried out. Data were collected from 235 couples carrying reciprocal translocations (1163 blastocysts) and 70 couples carrying Robertsonian translocations (351 blastocysts). The preimplantation genetic testing for structural rearrangement (PGT-SR) analysis of 1514 blastocysts were completed through next generation sequencing (NGS). RESULTS: After adjusting the confounding factors such as female age, AMH, ovarian stimulation regimen, and Gn dosage, the results showed that the risk for blastocyst chromosomal abnormalities was 0.41 [OR(95%CI), 1.41(1.06, 1.87), P < 0.05] times higher in female reciprocal translocation carriers and 1.02 [OR(95%CI), 2.02 (1.20, 3.40), P < 0.01] times higher in female Robertsonian translocation carriers compared with male carriers, respectively. Compared with male carriers, the risk of blastocyst chromosomal abnormalities was increased by 0.67 times [OR(95%CI), 1.67 (1.10, 2.56), P < 0.05] in female reciprocal translocation carriers over 30 years old and 1.06 times [OR(95%CI), 2.06 (1.02, 4.15), P = 0.0434, P < 0.05] in female Robertsonian translocation carriers between 25 and 30 years old. CONCLUSION Compared with male carriers, female carriers of reciprocal or Robertsonian translocations have a higher risk for producing embryos with chromosomal abnormalities, and their age may also be a risk factor.
Adult ; Blastocyst ; Chromosome Aberrations ; Female ; Genetic Testing/methods* ; Humans ; Male ; Pregnancy ; Preimplantation Diagnosis/methods* ; Retrospective Studies ; Translocation, Genetic

OBJECTIVE: To assess the value of preimplantation genetic test (PGT) based on next generation sequencing (NGS) for achieving pregnancy for 71 couples with one partner carrying a reciprocal or Robertsonian translocation. METHODS: Following blastocyst biopsy, whole genome of single cell was amplified, and PGT was performed by NGS. The subjects included 60 couples with one partner carrying a reciprocal translocation and 11 with one partner carrying a Robertsonian translocation. The results of PGT, implantation and prenatal diagnosis for all of the couples were analyzed. RESULTS: In total 301 embryos were obtained for the 71 couples through 92 ovulation cycles, 287 (95.3%) of which were successfully diagnosed by NGS. Eighty-five euploidy embryos were identified for the reciprocal translocation carrier group. In 18 cycles, no euploid embryo was obtained. Cancellation rate for the cycles was 19.5%. For reciprocal translocation carrier group and Robertsonian translocation carrier group, the rates for implantation, early abortion, and clinical pregnancy were 89.3% (42/47), 25.5% (12/47), 63.8% (30/47), and 88.8% (8/9), 22.2% (2/9), and 66.6% (6/9), respectively. The result of prenatal diagnosis was consistent with the that of PGT. CONCLUSION PGT based on NGS can effectively identify euploid embryos and reduce recurrent abortions and termination of pregnancies, achieving a satisfactory rate for clinical pregnancy.
Female ; Fertilization in Vitro ; Genetic Testing ; High-Throughput Nucleotide Sequencing ; Humans ; Pregnancy ; Preimplantation Diagnosis ; methods ; Translocation, Genetic

More than 7000 single gene diseases have been identified and most of them lack effective treatment. As an early form of prenatal diagnosis, preimplantation genetic diagnosis (PGD) is a combination of in vitro fertilization and genetic diagnosis. PGD has been applied in clinics for more than 20 years to avoid the transmission of genetic defects through analysis of embryos at early stages of development. In this paper, a review for the recent advances in PGD for single gene diseases is provided.
Animals ; Female ; Fertilization in Vitro ; Genetic Diseases, Inborn ; diagnosis ; embryology ; genetics ; Humans ; Pregnancy ; Preimplantation Diagnosis ; methods ; trends ; Prenatal Diagnosis ; methods ; trends

OBJECTIVETo establish a novel HLA genotyping method for preimplantation genetic diagnonis (PGD) using multiple displacement amplification-polymerase chain reaction-sequencing based technique (MDA-PCR-SBT).

METHODSPeripheral blood samples and 76 1PN, 2PN, 3PN discarded embryos from 9 couples were collected. The alleles of HLA-A, B, DR loci were detected from the MDA product with the PCR-SBT method. The HLA genotypes of the parental peripheral blood samples were analyzed with the same protocol. The genotypes of specific HLA region were evaluated for distinguishing the segregation of haplotypes among the family members, and primary HLA matching was performed between the embryos.

RESULTSThe 76 embryos were subjected to MDA and 74 (97.4%) were successfully amplified. For the 34 embryos from the single blastomere group, the amplification rate was 94.1%, and for the 40 embryos in the two blastomeres group, the rate was 100%. The dropout rates for DQ allele and DR allele were 1.3% and 0, respectively. The positive rate for MDA in the single blastomere group was 100%, with the dropout rates for DQ allele and DR allele being 1.5% and 0, respectively. The positive rate of MDA for the two blastomere group was 100%, with the dropout rates for both DQ and DR alleles being 0. The recombination rate of fetal HLA was 20.2% (30/148). Due to the improper classification and abnormal fertilized embryos, the proportion of matched embryos HLA was 20.3% (15/74),which was lower than the theoretical value of 25%.

CONCLUSIONPGD with HLA matching can facilitate creation of a HLA-identical donor (saviour child) for umbilical cord blood or bone marrow stem cells for its affected sibling with a genetic disease. Therefore, preimplantation HLA matching may provide a tool for couples desiring to conceive a potential donor progeny for transplantation for its sibling with a life-threatening disorder.

Blastocyst ; cytology ; metabolism ; Female ; Genotype ; Genotyping Techniques ; methods ; HLA Antigens ; genetics ; HLA-DQ beta-Chains ; genetics ; HLA-DRB1 Chains ; genetics ; Humans ; Polymerase Chain Reaction ; methods ; Pregnancy ; Preimplantation Diagnosis ; methods ; Reproducibility of Results ; Sequence Analysis, DNA ; methods

OBJECTIVETo estimate the value of blastocyst culture for preimplantation genetic diagnosis (PGD).

METHODSDay 3 embryos were biopsied and analyzed with fluorescence in situ hybridization (FISH) technique. Embryos with normal FISH results were cultured into blastocysts, and the ones with better morphology scores were transferred. Fourteen embryos with abnormal FISH results were cultured into blastocysts. Part of the cells taken from the blastocysts were amplified by whole genomic amplification (WGA) and assessed by array-based comparative genomic hybridization (array-CGH) analysis.

RESULTSSix blastocysts with normal FISH results were transferred in 5 cycles. Four healthy babies of 3 cycles were delivered. Another one was a singleton pregnancy but with embryo growth arrest, whose villus karyotype was normal. Fourteen embryos with abnormal FISH results were cultured into blastocysts and analyzed by array-CGH. Six blastocysts were normal by array-CGH.

CONCLUSIONFISH combined with blastocyst culture may further ensure the accuracy of PGD result. Detection at the blastocyst stage can avoid false positive results and mosaic interferences on Day 3 stage and are therefore more authentic.

Adult ; Blastocyst ; cytology ; Comparative Genomic Hybridization ; methods ; Embryo Transfer ; Female ; Genetic Diseases, Inborn ; diagnosis ; embryology ; genetics ; prevention & control ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Male ; Pregnancy ; Preimplantation Diagnosis ; methods

OBJECTIVETo investigate the efficiency of multi-round fluorescence in situ hybridization (FISH) and its influencing factors in preimplantation genetic diagnosis (PGD).

METHODSA total of 48 couples accepted PGD because of various reasons: 24 with Robertsonian translocations, 16 with reciprocal translocations, 2 with pericentric inversions, one with advanced maternal age who had a previous liveborn of Down syndrome, 3 suffered from sex chromosome abnormalities and 2 repeated spontaneous miscarriages. After 72 retrieval cycles, 432 cleavage stage embryos with more than six cells were biopsied on day three. Only intact nuclei (396) were hybridized in order to verify the chromosomal status of the individual embryos. If previous FISH has failed to give conclusive results while the nuclei remained undamaged, the nuclei were hybridized once again. A total of 870 times of hybridization were conducted to 396 nuclei. Signal identification rates of each round as well as the influence of different probes to the hybridization efficiency were compared. Factors leading to inconclusive FISH results were analyzed as well.

RESULTSFive hundred and thirty five out of 870 hybridizations gave identifiable signals (61.5%). The second and third round FISH showed the best signals with an identification rate of 71.8% and 77.4%, respectively, which were significantly higher than those of the first round (52.8%, P < 0.01), the fourth round (55.8%, P < 0.05, P < 0.01), the fifth round (54.5%, P < 0.05) and the sixth round (27.3%, P < 0.01). The identification rate of centromere specific probe signals (CEP group) was 80.3% and the former three rounds in this group got the best quality of signals with an identification rate of 85.7%, 85.1% and 88.0%, respectively, which was significantly higher than that of the latter three rounds. The identification rate of other probe was much lower than with the CEP probe (55.2% vs. 80.3%, P < 0.01) and the best quality of signal in this group was achieved in the fifth round (72.7%), followed by the second round (66.1%) and the third round (63.8%). The identification rate of the first round (50.3%) and the sixth round (22.2%) were significantly lower compared with the second round (P < 0.01). During the 6 rounds of FISH, 335 hybridizations did not give conclusion results (38.5%, 335/870). The main cause of unidentification was weak signals (20.9%, 182/870). Other common factors included background interference (7.6%, 66/870) and failed hybridization (6.1%, 53/870). Rare causes included nucleus damage (1.8%, 16/870), nucleus loss (1.1%, 10/870) and signal split/overlap (0.9%, 8/870).

CONCLUSIONMulti-round FISH can improve the utility of single nucleus in PGD and the former three rounds have the highest efficiency. The hybridization effect of CEP is better than other probe. Poor signal quality is the common cause of unidentification results.

Female ; Genetic Testing ; methods ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Male ; Pregnancy ; Preimplantation Diagnosis ; methods ; Prenatal Diagnosis ; Translocation, Genetic

Multiple displacement amplification (MDA) is a new technology for whole genome amplification (WGA), which can generate large amount of high-quality DNA and features high amplification efficiency and fidelity. MDA combined with conventional PCR techniques has been successfully applied for preimplantation genetic diagnosis, which has broaden latter's clinical applications.
Genome, Human ; Humans ; Nucleic Acid Amplification Techniques ; methods ; Polymerase Chain Reaction ; methods ; Preimplantation Diagnosis ; methods

INTRODUCTIONWe aimed to develop and implement a short tandem repeat (STR) polymerase chain reaction alternative to fluorescence in situ hybridisation (FISH) for the preimplantation genetic diagnosis (PGD) of chromosomal translocations.

METHODSSelected informative STRs located on translocated arms of relevant chromosomes were used to discriminate between normal and unbalanced chromosome states in each embryo.

RESULTSPGD cycles were performed on five couples where one spouse carried a balanced translocation. 27 embryos were analysed, of which 12 were normal/balanced, 12 were abnormal/unbalanced and three were indeterminate. Four PGD cycles proceeded to embryo transfer, of which two led to pregnancy. The first pregnancy showed a normal male karyotype, and a healthy baby was delivered at term. A second pregnancy unexpectedly miscarried in the second trimester from unknown causes.

CONCLUSIONSTR analysis is a simple and suitable alternative to FISH for detecting unbalanced chromosomal states in preimplantation embryos.

Female ; Fertilization in Vitro ; Humans ; Male ; Microsatellite Repeats ; genetics ; Polymerase Chain Reaction ; methods ; Polymorphism, Genetic ; genetics ; Pregnancy ; Pregnancy Outcome ; Preimplantation Diagnosis ; methods ; Translocation, Genetic ; genetics