Identification and interruption of inheritance of familial cryptic translocations: A case report.

BACKGROUND: Cryptic translocations can be identified via genetic analysis of aborted tissues or malformed infants, but it is difficult to deduce the parental origins of the translocations. In the absence of such information, it is not easy to distinguish translocations from normal embryos during pre-implantation genetic testing, that seeks to block familial transmission of translocations. METHODS: Here, we present a new method that detects cryptic translocations and blocks familial transmission thereof. Whole-genome, low-coverage mate-pair sequencing (WGLMPS) revealed chromosome breakpoint sequences, and preimplantation genetic haplotyping (PGH) was then used to discard embryos with cryptic translocations. RESULTS: Cryptic translocations were found in all four families, and familial transmission was successfully blocked in one family. CONCLUSION: Whole-genome, low-coverage mate-pair sequencing combined with preimplantation genetic haplotyping methods powerfully and practically identify cryptic translocations and block familial transmissions.

Improved pregnancy outcomes from mosaic embryos with lower mtDNA content: a single-center retrospective study.

RESEARCH QUESTION: The purpose of this study is to investigate whether the mitochondrial DNA (mtDNA) content can reflect the state of mosaic embryos. DESIGN: The study included 1669 blastocysts derived from 394 PGT-A cycles between January 2018 and December 2020, in which preimplantation genetic testing for aneuploidy was performed and mtDNA content was determined. The standard deviation (SD) of whole genomic sequencing data was calculated for quality control. mtDNA content was measured as the proportion of mtDNA to genomic DNA. 1558 blastocysts with SD values less than 4.0 and mtDNA values less than 0.4% were selected for statistical analysis. RESULTS: The mtDNA content of the PGT mosaic group was significantly higher than that of the PGT normal group (P < 0.001). Twenty-six mosaic embryos were transferred, and the results were as follows: 2 out of 26 had undergone a spontaneous miscarriage, 15 were not pregnant, and 9 resulted in a live birth. There were significant differences in the mtDNA content between the miscarriage/non-pregnancy group and the live birth group (**P < 0.01; ***P < 0.001). There was no mosaic embryo with more than 0.157% mtDNA content found in the live birth group. CONCLUSIONS: This study demonstrates that mtDNA analysis has the ability to identify mosaic embryos with high developmental potential. It can be a valuable supplementary index for the selection of mosaic embryos for transfer. Larger studies with a greater sample size will further our understanding of the relationships between metabolic activity and mosaicism.

[Relationship of sperm morphology with the outcomes of in vitro fertilization and embryo transfer].

OBJECTIVE: To study the application value of normal sperm morphology on the outcomes of classic in vitro fertilization and embryo transfer (IVF-ET). METHODS: This study included 659 infertile couples admitted to our center for IVF-ET. Based on the percentage of morphologically normal sperm (MNS), we divided the patients into groups A (n = 112, MNS < 2%), B (n = 180, MNS > or = 2 - < 4%), C (n = 74, MNS > or = 4 - < 5%), and D (n = 293, MNS > or = 5%), and compared the rates of fertilization, normal fertilization, embryos obtained, biochemical pregnancy, clinical pregnancy, implantation, and live birth among different groups. RESULTS: The mean fertilization rate was significantly higher in groups C (71.90%) and D (72.89%) than in A (57.97%) and B (63.29%) (P < 0.05), with no remarkable differences either between A and B (P > 0.05) or between C and D (P > 0.05). The normal fertilization rate was also significantly higher in group D (57.16%) than in A (46.52%) and B (50.89%) (both P < 0.05) as well as in C (54.67%) than in A (P < 0.05). The rate of embryos obtained, too, was markedly higher in group D (55.62%) than in B (45.75%) (P < 0.05), but none with remarkable difference from other groups (all P > 0.05). There were no statistically significant differences among the four groups in the rates of biochemical pregnancy, clinical pregnancy, implantation, abortion, and live birth (all P > 0.05). CONCLUSION: The rate of MNS had some influence on IVF-ET, and 5% MNS exhibited a higher value than 4% MNS in predicting the outcomes of IVF.

[Analysis of sex chromosome mosaicisms in early cleavage-stage human embryos and blastocysts with poor embryo quality scores].

OBJECTIVE: To analyze sex chromosome mosaicisms in early cleavage-stage human embryos and blastocysts with poor embryo quality score based on the numbers of pronucleus(PN) zygotes using X,Y dual color fluorescence in situ hybridization (FISH), and to discuss the possible mechanisms. METHODS: Fresh or frozen-thawed early cleavage-stage human embryos and blastocysts with poor embryo quality score not suitable for embryo transfer were studied with dual color FISH. RESULTS: Double signal rate of 2PN among early cleavage-stage embryos was 66.67%, which was significantly higher than 1PN and 3PN embryos. Single signal rate of 1PN early cleavage-stage embryos was 90.41%, which was significantly higher than 2PN and 3PN ones. Three signal rate of 3PN early cleavage-stage embryos was 28.00%, which was significantly higher than 1PN and 2PN ones. Double signal rate of 3PN ones was 46.00%, which was significantly higher than 1PN ones. The polyploid rate of frozen-thawed early cleavage-stage embryos was 23.53%, which was slightly higher than that of fresh embryos, but with no statistical significance. The mosaicism rate of 24 blastocysts was 100.00% and the double signal dominant (≥ 50%) rate was 62.50%, which was significantly higher than the rate of early cleavage-stage embryos. CONCLUSION: Using 2PN as the criterion for embryo quality score cannot guarantee the selection of normal fertilized embryo for transplantation. Frozen-thawed embryos may harbor more polyploid cells. To avoid the selection of embryos with abnormal chromosomes, combinations of pre-implantation genetic diagnosis (PGD) and prenatal diagnosis are necessary. Meanwhile, blastocysts with poor quality scores may provide an important source for embryo stem cells.