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*

OBJECTIVE: To assess the value of single sperm sequencing in preimplantation genetic testing for monogenic disease (PGT-M). METHODS: A Chinese couple with two children whom had died of Spinal muscular atrophy (SMA) and attended the Jiangxi Provincial Maternal and Child Health Care Hospital in June 2020 was selected as the subject. Eleven single sperm samples were isolated by mechanical immobilization and subjected to whole genome amplification. Real-time PCR and Sanger sequencing were used to detect the SMN1 variants in the single sperm samples. Genomic DNA of the wife, her parents and the husband, as well as one single sperm sample harboring the SMN1 variant and two single sperm samples without the variant were used for the linkage analysis. Targeted capture and high-throughput sequencing were carried out to test 100 single nucleotide polymorphisms distributed within 2 Mb up- and downstream the variant site. The haplotypes linked with the SMN1 variants were determined by linkage analysis. Blastocyst embryos were harvested after fertilizing by intracytoplasmic sperm injection. Cells from the trophoblasts of each embryo were biopsied and subjected to whole genome amplification and targeted capture and high-throughput sequencing to determine their carrier status. Chromosomal aneuploidy of wild-type embryos was excluded. An euploid embryo of high quality was transferred. Amniotic fluid sample was taken at 18 weeks of gestation to confirm the status of the fetus. RESULTS: Genetic testing showed that the couple both had deletion of exons 7 ~ 8 of the SMN1 gene. The wife has inherited the deletion from her father, while the husband was de novo. The haplotypes of the husband were successfully constructed by single sperm sequencing. Preimplantation genetic testing has indicated that 5 embryos had harbored the heterozygous variant, 4 embryos were of the wild type, among which 3 were euploid. Prenatal diagnosis during the second trimester of pregnancy has confirmed that the fetus did not carry the deletion. CONCLUSION By single sperm sequencing and PGT-M, the birth of further affected child has been successfully avoided.
Humans ; Pregnancy ; Female ; Child ; Male ; Preimplantation Diagnosis ; East Asian People ; Semen ; Genetic Testing ; Muscular Atrophy, Spinal/genetics* ; Aneuploidy ; Blastocyst/pathology* ; High-Throughput Nucleotide Sequencing ; Spermatozoa

Mosaic embryos contain two or more genetically distinct cell lines, which can be detected by pre-implantation genetic testing for aneuploidy. At present, it has been reported that mosaic embryo transfer can lead to healthy live births. In order to prevent severe adverse pregnancy outcomes, such as implantation failure, abortion, congenital malformation and neonatal death after implantation of mosaic embryos, it is critical to carry out genetic counseling, prenatal diagnosis and pregnancy supervision for mosaic embryo transfer. This article reviews the selection of mosaic embryos, the pregnancy outcomes of mosaic embryo transfer, and the safety of offspring, in order to provide references for the clinical practice of mosaic embryo transfer.
Pregnancy ; Female ; Infant, Newborn ; Humans ; Preimplantation Diagnosis ; Embryo Transfer ; Pregnancy Outcome ; Genetic Testing ; Embryo Implantation/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 identify the pathogenic variant for a husband with osteogenesis imperfecta and provide preimplantation genetic testing (PGT) for the couple. METHODS: High-throughput sequencing and Sanger sequencing were carried out to identify the pathologic variant in the husband patients. PGT of embryos was performed through direct detection of the mutation site. Meanwhile, chromosome aneuploidy of the blastocysts was screened. Following transplantation, cytogenetic and genetic testing of fetal amniotic fluid sample was carried out during mid-pregnancy. Chromosome copy number variant (CNV) was detected at multiple sites of the placenta after delivery. RESULTS: The husband was found to harbor heterozygous c.544-2A>G variant of the COL1A1 gene. The same variant was not detected in either of his parents. PGT revealed that out of three embryos of the couple, one was wild-type for the c.544-2A site but mosaicism for duplication of 16p13.3.11.2. The other two embryos were both heterozygous for the c.544-2A>G variant. Following adequate genetic counseling, the wild-type embryo was transplanted. Amniotic fluid testing confirmed that the fetus had normal chromosomes and did not carry the c.544-2A>G variant. The copy number of chromosomes at different parts of placenta was normal after birth. CONCLUSION For couples affected with monogenic disorders, e.g., osteogenesis imperfecta, direct detection of the mutation site may be used for PGT after identifying the pathogenic variant. After adequate genetic counseling, prenatal diagnosis must be carried out to ensure the result.
Aneuploidy ; China ; Female ; Genetic Testing ; Humans ; Osteogenesis Imperfecta/genetics* ; Pregnancy ; Preimplantation Diagnosis

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 explore the application value of next generation sequencing (NGS) in preimplantation genetic diagnosis of α/β complex thalassemia couple. METHODS: The coding regions of α-globin genes (HBA1, HBA2) and β-globin gene (HBB) were selected as the target regions. The high-density and closely linked single nucleotide polymorphism (SNP) sites were selected as the genetic linkage markers in the upstream and downstream 2M regions of the gene. After NGS, the effective SNP sites were selected to construct the haplotype of the couple, and the risk chromosome of the mutation carried by the couple was determined. The NGS technology was used to sequence the variations of HBA1, HBA2 and HBB directly and construct haplotype linkage analysis for preimplantation genetic diagnosis. RESULTS: Direct sequencing and haplotype linkage analysis of HBA1, HBA2 and HBB showed that two of the six blastocysts were α/β complex thalassemia, one was β-thalassemia heterozygote, two were α-thalassemias heterozygotes, and one was intermediate α-thalassemia. A well-developed embryo underwent preimplantation genetic diagnosis was implanted into the mother's uterus, and a healthy infant was born at term. CONCLUSION Preimplantation genetic diagnosis can be carried out by NGS technology in α/β complex thalassemia couples, and abortion caused by aneuploid embryo selection can be avoided.
Female ; High-Throughput Nucleotide Sequencing ; Humans ; Mutation ; Pregnancy ; Preimplantation Diagnosis ; alpha-Thalassemia ; beta-Globins/genetics* ; beta-Thalassemia/genetics*

OBJECTIVE: To assess the application value of mapping allele with resolved carrier status (MaReCs) technique for preimplantation genetic testing (PGT). METHODS: The characteristics of MaReCs for PGT and outcome of patients were retrospectively analyzed. RESULTS: Compared with those who could not use the technique, carriers who have used the MaReCs technique were younger, had significantly higher level of anti-Mullerian hormone, more antral follicles, occytes, mature occytes, biopsied embryos and euploid embryos, and lower risks for de novo chromosomal abnormality (P<0.05). It was necessary for couples with fewer oocytes, mature oocytes and balstocyst to preserve discarded embryos to facilitate the test. Carriers who have used the MaReCs technique had higher clinical pregnancy rate and abortion rate compared with those undergoing routine PGT, albeit no significant difference was found between the two groups (P> 0.05). Carriers undergoing MaReCs test could preferentially select embryos with normal chromosome structures for the transfer. CONCLUSION Application of MaReCs has a prerequisite for having a minimum number of occytes and biopsied embryos and using discarded embryos sometimes. MaReCs is efficient for the detection of carrier status of embryos and attaining higher rate of pregnancy and live birth, which can significantly improve the outcome for couples carrying chromosomal translocations.
Alleles ; Aneuploidy ; Blastocyst ; Female ; Fertilization in Vitro ; Genetic Testing ; Humans ; Pregnancy ; Preimplantation Diagnosis ; Retrospective Studies ; Translocation, Genetic

OBJECTIVE: To carry out preimplantation genetic testing (PGT) for a couple where the husband was affected by osteogenesis imperfecta combined with balanced translocation using the karyomapping technique. METHODS: Blastocysts were detected using karyomapping, the carrier status of COL1A1 c.760G>A (p.Gly254Arg) variant and the carrier status of the translocated chromosome were analyzed simultaneously. RESULTS: For a total of 10 blastocysts, two euploid blastocysts were found to not carry the COL1A1 c.760G>A (p.Gly254Arg) variant but a balanced translocation. After transplanting one of the blastocysts, clinical pregnancy was achieved. Amniocentesis at 18th gestational week and prenatal genetic testing was in keeping with the result of PGT.A healthy female was born at 40+4 weeks gestation. CONCLUSION For patients simultaneously carrying genetic variant and balanced chromosomal translocation, PGT can be performed with efficiency by the use of karyomapping method.
Blastocyst ; Female ; Fertilization in Vitro ; Genetic Testing ; Humans ; Osteogenesis Imperfecta/genetics* ; Pregnancy ; Preimplantation Diagnosis ; Spouses ; Translocation, Genetic

Female ; Fertilization in Vitro ; Humans ; Klinefelter Syndrome/genetics* ; Pregnancy ; Preimplantation Diagnosis ; Sperm Injections, Intracytoplasmic