PURPOSE: Preimplantation genetic testing for monogenic disorders (PGT-M) allows early diagnosis in embryos conceived in vitro. PGT-M helps to prevent known genetic disorders in affected families and ensures that pathogenic variants in the male or female partner are not passed on to offspring. The trend in genetic testing of embryos is to provide a comprehensive platform that enables robust and reliable testing for the causal pathogenic variant(s), as well as chromosomal abnormalities that commonly occur in embryos. In this study, we describe PGT protocol that allows direct mutation testing, haplotyping, and aneuploidy screening. METHODS: Described PGT protocol called OneGene PGT allows direct mutation testing, haplotyping, and aneuploidy screening using next-generation sequencing (NGS). Whole genome amplification product is combined with multiplex PCR used for SNP enrichment. Dedicated bioinformatic tool enables mapping, genotype calling, and haplotyping of informative SNP markers. A commercial software was used for aneuploidy calling. RESULTS: OneGenePGT has been implemented for seven of the most common monogenic disorders, representing approximately 30% of all PGT-M indications at our IVF centre. The technique has been thoroughly validated, focusing on direct pathogenic variant testing, haplotype identification, and chromosome abnormality detection. Validation results show full concordance with Sanger sequencing and karyomapping, which were used as reference methods. CONCLUSION: OneGene PGT is a comprehensive, robust, and cost-effective method that can be established for any gene of interest. The technique is particularly suitable for common monogenic diseases, which can be performed based on a universal laboratory protocol without the need for set-up or pre-testing.

• MeSH
• aneuploidie MeSH
• blastocysta patologie   MeSH
• genetické testování metody   MeSH
• lidé MeSH
• mutace genetika   MeSH
• preimplantační diagnóza * metody   MeSH
• těhotenství MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Genomics Quality Assessment has provided external quality assessments (EQAs) for preimplantation genetic testing (PGT) for 12 years for eight monogenic diseases to identify sub-optimal PGT strategies, testing and reporting of results, which can be shared with the genomics community to aid optimised standards of PGT services for couples. METHOD: The EQAs were provided in two stages to mimic end-to-end protocols. Stage 1 involved DNA feasibility testing of a couple undergoing PGT and affected proband. Participants were required to report genotyping results and outline their embryo testing strategy. Lymphoblasts were distributed for mock embryo testing for stage 2. Submitted clinical reports and haplotyping results were assessed against peer-ratified criteria. Performance was monitored to identify poor performance. RESULTS: The most common testing methodology was short tandem repeat linkage analysis (59%); however, the adoption of single nucleotide polymorphism-based platforms was observed and a move from blastomere to trophectoderm testing. There was a variation in testing strategies, assigning marker informativity and understanding test limitations, some clinically unsafe. Critical errors were reported for genotyping and interpretation. CONCLUSION: EQA provides an overview of the standard of preimplantation genetic testing-M clinical testing and identifies areas of improvement for accurate detection of high-risk embryos.

• MeSH
• aneuploidie MeSH
• blastocysta MeSH
• genetické testování metody   MeSH
• lidé MeSH
• preimplantační diagnóza * metody   MeSH
• těhotenství MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• asistovaná reprodukce MeSH
• genetické testování MeSH
• lidé MeSH
• preimplantační diagnóza * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

Chromosomal mosaicism detected during preimplantation genetic testing for aneuploidy (PGT-A) and its impact on embryo implantation have been widely discussed, and healthy live births from mosaic embryos were reported by many groups. On the other hand, only very few studies have focused on segmental chromosome aneuploidies and their clinical impact. Eighty-nine embryos with various PGT-A results (trophectoderm 1: TE1) were re-analysed using a second trophectoderm biopsy (TE2) and the rest of the embryo (RE) for testing. Of 19 euploid TE1 biopsies, 18 were concordant across TE2 and RE. Similarly, whole chromosomal aneuploidies were concordant in 59 of 62 TE1-TE2 and 58 TE1-RE. In contrast, from 31 segmental aneuploidies detected in TE1, only 15 were observed again in TE2 and 14 in RE. If a TE1 segmental abnormality appeared again in TE2, it was almost always present in RE (17/18) as well. Moreover, when a TE1 segmental abnormality was not detected in TE2, in 12 out of 13 cases RE was also unaffected. Similarly, only 1 of 26 TE1 whole chromosome mosaics were repeated in TE2 and 7 in RE. Our study confirms that euploid and whole chromosomal aneuploidy results are highly predictive of the embryo. In contrast, mosaicism has a very low concordance rate. Most importantly, re-biopsy of embryos with segmental aneuploidies demonstrated that they are mostly not uniform across the embryo. Finally, in the case of segmental aneuploidy, the second biopsy enables an accurate prediction of the real status of the embryo and could be offered to patients undergoing PGT-A.

• MeSH
• aneuploidie * MeSH
• biopsie MeSH
• embryo savčí * MeSH
• genetické testování metody   MeSH
• lidé MeSH
• mozaicismus MeSH
• preimplantační diagnóza metody   MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• validační studie MeSH

RESEARCH QUESTION: What is the incidence and origin of meiotic whole and segmental aneuploidies detected by karyomapping at a blastocyst stage in human-derived IVF embryos? What is the distribution of various types of errors, including rare chromosomal abnormalities? DESIGN: The incidence of chromosomal aneuploidies was assessed in 967 trophectoderm biopsies from 180 couples who underwent 215 cycles of IVF with preimplantation genetic testing for monogenetic disease with a known causal mutation with a mean maternal age of 32.7 years. DNA from both parents and a reference sample was genotyped together with the analysed trophectoderm samples by karyomapping (single-nucleotide-polymorphism-based array). RESULTS: Chromosomal abnormalities were detected in 31% of the analysed samples. At least one whole chromosomal aneuploidy was detected in 27.1% of the trophectoderm biopsies, whereas a segmental aneuploidy was detected in 5.1% of the trophectoderm biopsies. Our results reveal that segmental aneuploidies predominantly affect paternally derived chromosomes (70.4%; P < 0.01) compared with whole chromosomal aneuploidies that more frequently affect maternally derived chromosomes (90.1%; P < 0.0001). Also, the frequency of meiosis I (MI) and meiosis II (MII) errors was established in meiotic trisomies; MI errors were observed to be more frequent (n = 102/147 [69.4%]) than MII errors (n = 45/147 [30.6%]). CONCLUSIONS: Karyomapping is a robust method that is suitable for preimplantation genetic testing for monogenetic disease and for detecting meiotic aneuploidies, including meiotic segmental aneuploidies, and provides complex information about their parental origin. Our results revealed that segmental aneuploidy more frequently affects paternal chromosomes compared with whole chromosomal aneuploidy in human IVF embryos at the blastocyst stage.

• MeSH
• aneuploidie * MeSH
• chromozomální aberace * MeSH
• chromozomální poruchy epidemiologie   MeSH
• dospělí MeSH
• fertilizace in vitro * MeSH
• genetické testování MeSH
• incidence MeSH
• karyotypizace MeSH
• lidé MeSH
• meióza * MeSH
• preimplantační diagnóza metody   MeSH
• těhotenství MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

In this study, chromosomal imbalances in tumor tissues (lymphomas) and nucleotide changes in tumor suppressor TP53 were studied in a Bernese Mountain dog bitch and a cross breed bitch. Using comparative genomic hybridization, numerous chromosomal rearrangements were detected, which indicated the heterogeneity in tumor growth: in the cross breed bitch, a deletion on the chromosome 9, and duplications on chromosomes 5, 8 and 17 have been found. In the Bernese Mountain Dog bitch, losses on chromosomes 1, 5, 8, 12, 18, 22, 27, 29 and gains on chromosomes 1, 2, 9, 11, 15, 16, 18, 20, 23, 24, 25, 28, 29, 30, 34, 36, 37 and 38 were identified. With the sequencing of the TP53 gene, one silent mutation, transition A/G at position 138 in exon 5 was detected, without changing the amino acid.

• MeSH
• chromozomální aberace * MeSH
• chromozomy genetika   MeSH
• DNA genetika   MeSH
• exony genetika   MeSH
• genová přestavba genetika   MeSH
• geny p53 genetika   MeSH
• lymfom genetika   patologie   veterinární   MeSH
• mutace MeSH
• nemoci psů genetika   MeSH
• polymerázová řetězová reakce metody   MeSH
• psi MeSH
• sekvenční analýza DNA MeSH
• srovnávací genomová hybridizace metody   MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Východiska: Asistovaná reprodukce, stejně jako samotné těhotenství u pacientek ohrožených karcinomem prsu či jinými dědičnými nádorovými onemocněními představuje jedno z velmi diskutovaných témat. Je nutno připustit, že v minulosti byl přístup k přání otěhotnět, případně léčbě neplodnosti u žen po léčbě karcinomu prsu více než zdrženlivý. Dostupné informace naznačují, že karcinom prsu, pokud to průběh léčby umožňuje, není kontraindikací k těhotenství ani k asistované reprodukci. Naopak, v současnosti přináší tento přístup možnost vyloučení přenosu genetického rizika na plod pomocí preimplantační genetické diagnostiky. Cíl: V tomto přehledovém článku si klademe za cíl shrnout dosavadní poznatky a publikované informace o rizicích a úskalích těhotenství pacientek ohrožených karcinomem prsu. Zároveň uvádíme současné možnosti a ideální postupy pro zachování plodnosti před plánovanou léčbou a pro provedení metod asistované reprodukce s využitím nejnovějších postupů, zaručujících co možná nejbezpečnější průběh. Ve druhé části práce je pak popsána moderní molekulárně genetická metoda karyomapping, jež přináší nové možnosti preimplantační genetické diagnostiky s cílem vyloučení zárodečné mutace v případě dědičných predispozic k nádorovým onemocněním. Rapidní vývoj metod preimplantační genetické diagnostiky je demonstrován především možností zachytit současně se sledovanou mutací také aneuploidie všech chromozomů a v neposlední řadě zkrácením doby nutné k přípravě metody na několik dní.

Background: Assisted reproduction, as well as pregnancy itself, in patients with breast cancer or other hereditary type of cancer, is a widely discussed topic. In the past, patients treated for breast cancer were rarely involved in the discussion about reproductive possibilities or infertility treatment. However, current knowledge suggests, that breast cancer is neither a contraindication to pregnancy, nor to assisted reproduction techniques. On the contrary, assisted reproduction and preimplantation genetic diagnosis methods might prevent the transmission of genetic risks to the fetus. Aim: In this review we summarize data concerning pregnancy risks in patients with increased risk of breast cancer. In addition, we introduce current possibilities and approaches to fertility preservation prior to assisted reproduction treatment as well as novel methods improving the safety of fertility treat­ment. In the second part of this review, we focus on karyomapping – an advanced molecular genetic tool for elimination of germinal mutations in patients with predisposition to cancer. Moreover, the rapid development of preimplantation genetic diagnosis methods contributes to detection of both chromosomal aneuploidy and causal mutations in a relatively short time-span. Key words: breast neoplasms – hereditary cancer syndromes – assisted reproduction – ovarian reserve – hormonal stimulation – preimplantation diagnosis – karyom The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 19. 10. 2015 Accepted: 20. 11. 2015

• Klíčová slova
• karyomapping,
• MeSH
• amenorea chemicky indukované   MeSH
• aneuploidie MeSH
• antitumorózní látky škodlivé účinky   MeSH
• asistovaná reprodukce * MeSH
• dědičný syndrom nádoru prsu a vaječníků genetika   MeSH
• fertilizující látky ženské škodlivé účinky   MeSH
• genetické testování metody   MeSH
• indukce ovulace metody   škodlivé účinky   MeSH
• kryoprezervace MeSH
• lidé MeSH
• nádorové komplikace v těhotenství MeSH
• nádory prsu * genetika   MeSH
• odběr oocytu MeSH
• ovariální rezerva účinky léků   MeSH
• preimplantační diagnóza * metody   MeSH
• tamoxifen MeSH
• těhotenství MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• přehledy MeSH

Bovine embryos are now routinely used in agricultural systems as a means of disseminating superior genetics worldwide, ultimately with the aim of feeding an ever-growing population. Further investigations, common for human IVF embryos, thus have priority to improve cattle IVF, as has screening for aneuploidy (abnormal chromosome number). Although the incidence and consequences of aneuploidy are well documented in human preimplantation embryos, they are less well known for the embryos of other animals. To address this, we assessed aneuploidy levels in thirty-one 2-cell bovine embryos derived from early- and late-cleaving zygotes. Contemporary approaches ( Whole Genome Amplification and next-generation sequencing) allowed aneuploidy assessment for all chromosomes in oocytes from donors aged 4-7 years. We also quantified mitochondrial DNA (mtDNA) levels in all blastomeres assessed, thereby testing the hypothesis that they are related to levels of aneuploidy. The overall incidence of aneuploidy in this cohort of bovine embryos was 41.1% and correlated significantly with the timing of cleavage (77.8% in late-cleaving vs. 31.8% in early-cleaving embryos). Moreover, based on mtDNA sequence read counts, we observed that the median mtDNA quantity is significantly lower in late-cleaving embryos. These findings further reinforce the use of the bovine system as a model for human IVF studies.

• MeSH
• aneuploidie * MeSH
• blastomery metabolismus   MeSH
• buněčné dělení * MeSH
• časové faktory MeSH
• cytokineze MeSH
• embryo savčí cytologie   embryologie   metabolismus   patologie   MeSH
• fertilizace in vitro metody   veterinární   MeSH
• mitochondriální DNA analýza   MeSH
• sekvenční analýza DNA metody   veterinární   MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• skot MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In pigs, in vitro production is difficult with a high occurrence of polyspermy and low blastocyst formation rates. To test the hypothesis that this may, at least in part, be due to chromosomal errors, we employed whole genome amplification and comparative genomic hybridization, performing comprehensive chromosome analysis to assess both cells of the two-cell stage in vitro porcine embryos. We thus described the incidence, nature and origin of chromosome abnormalities, i.e. whether they derived from incorrect meiotic division during gametogenesis or aberrant mitotic division in the zygote. We observed that 19 out of 51 (37%) of two-cell stage early pig IVP embryos had a chromosome abnormality, mostly originating from an abnormal division in the zygote. Moreover, we frequently encountered multiple aneuploidies and segmental chromosome aberrations. These results indicate that the pig may be particularly sensitive to in vitro production, which may, in turn, be due to incorrect chromosome segregations during meiosis and early cleavage divisions. We thus accept our hypothesis that chromosome abnormality could explain poor IVP outcomes in pigs.

• MeSH
• aneuploidie MeSH
• chromozomální aberace * MeSH
• embryo savčí MeSH
• fertilizace in vitro veterinární   MeSH
• srovnávací genomová hybridizace MeSH
• Sus scrofa embryologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH