BACKGROUND Post-zygotic chromosome segregation errors are very common in human embryos after in vitro fertilization, resulting in mosaic embryos. However, the significance of mosaicism for the ...developmental potential of early embryos is unknown. We assessed chromosomal constitution and development of embryos from compaction to the peri-implantation stage. METHODS From 112 cryopreserved Day 4 human embryos donated for research, 21 were immediately fixed and all cells were analysed by fluorescent in situ hybridization (FISH) for chromosomes 1, 7, 13, 15, 16, 18, 21, 22, X and Y. The remaining 91 embryos were thawed, with 54 embryos undergoing biopsy of one or two cells which were fixed and analysed by FISH. Biopsied embryos were kept in standard culture conditions for 24 h. Embryos arrested before cavitation (n = 24) were fixed whereas developing Day 5 blastocysts (n = 24) were co-cultured for a further 72 h on an endometrial monolayer followed by fixation. Cell numbers were counted and all nuclei were analysed by FISH. Data from a previous FISH analysis on cryopreserved good-quality Day 5 blastocysts (n = 36) were also included in the present study. RESULTS FISH analysis was successful for 18 Day 4 fixed embryos and, according to our definition, 83% were mosaic and 11% showed a chaotic chromosomal constitution. FISH analysis of two blastomeres from Day 4 developing embryos showed that 54% were mosaic, 40% were normal and 6% were abnormal. Analysis of Day 4, 5 and 8 whole embryos showed a decrease in incidence of mosaicism over time, from 83% on Day 4 to 42% on Day 8. A significant positive correlation was observed between the total cell number and the percentage of normal cells in developing Day 5 and Day 8 embryos but not in developing Day 4 or embryos arrested before cavitation. CONCLUSIONS These data suggest that both the developmental arrest of a significant proportion of mosaic embryos on Day 4, and the cell death or reduced proliferation of aneuploid cells within an embryo may be responsible for the observed decrease of aneuploid blastomeres from compaction to the peri-implantation stage.
Noninvasive prenatal testing (NIPT) for fetal aneuploidy screening using cell-free DNA derived from maternal plasma can incidentally raise suspicion for cancer. Diagnostic routing after malignancy ...suspicious-NIPT faces many challenges. Here, we detail malignancy suspicious-NIPT cases, and describe the clinical characteristics, chromosomal aberrations, and diagnostic routing of the patients with a confirmed malignancy. Clinical lessons can be learned from our experience.
Patients with NIPT results indicative of a malignancy referred for tumor screening between April 2017 and April 2020 were retrospectively included from a Dutch nationwide NIPT implementation study, TRIDENT-2. NIPT profiles from patients with confirmed malignancies were reviewed, and the pattern of chromosomal aberrations related to tumor type was analyzed. We evaluated the diagnostic contribution of clinical and genetic examinations.
Malignancy suspicious-NIPT results were reported in 0.03% after genome-wide NIPT, and malignancies confirmed in 16 patients (16/48, 33.3%). Multiple chromosomal aberrations were seen in 23 of 48 patients with genome-wide NIPT, and a malignancy was confirmed in 16 patients (16/23, 69.6%). After targeted NIPT, 0.005% malignancy suspicious-NIPT results were reported, in 2/3 patients a malignancy was confirmed. Different tumor types and stages were diagnosed, predominantly hematologic malignancies (12/18). NIPT data showed recurrent gains and losses in primary mediastinal B-cell lymphomas and classic Hodgkin lymphomas. Magnetic resonance imaging and computed tomography were most informative in diagnosing the malignancy.
In 231,896 pregnant women, a low percentage (0.02%) of NIPT results were assessed as indicative of a maternal malignancy. However, when multiple chromosomal aberrations were found, the risk of a confirmed malignancy was considerably high. Referral for extensive oncologic examination is recommended, and may be guided by tumor-specific hallmarks in the NIPT profile.
In the past 30 years karyotyping was the gold standard for prenatal diagnosis of chromosomal aberrations in the fetus. Traditional karyotyping (TKT) has a high accuracy and reliability. However, it ...is labor intensive, the results take 14-21 days, the costs are high and unwanted findings such as abnormalities with unknown clinical relevance are not uncommon. These disadvantages challenged the practice of karyotyping. Multiplex ligation-dependent probe amplification (MLPA) is a new molecular genetic technique in prenatal diagnosis. Previous preclinical evidence suggests equivalence of MLPA and traditional karyotyping (TKT) regarding test performance.
The proposed study is a multicentre diagnostic substitute study among pregnant women, who choose to have amniocentesis for the indication advanced maternal age and/or increased risk following prenatal screening test. In all subjects, both MLPA and karyotyping will be performed on the amniotic fluid sample. The primary outcome is diagnostic accuracy. Secondary outcomes will be maternal quality of life, women's preferences and costs. Analysis will be intention to treat and per protocol analysis. Quality of life analysis will be carried out within the study population. The study aims to include 4500 women.
The study results are expected to help decide whether MLPA can replace traditional karyotyping for 'low-risk' pregnancies in terms of diagnostic accuracy, quality of life and women's preferences. This will be the first clinical study to report on all relevant aspects of the potential replacement.
The protocol is registered in the clinical trial register number ISRCTN47252164.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The objective of this review was to gain understanding about unexpected findings in prenatal cytogenetic diagnosis. This category of results might be excluded from prenatal testing when new molecular ...tests such as I-FISH and QF-PCR will be applied in a future scenario of targeted testing. The literature was systematically searched for publications wherein the term unexpected or a synonym refers to testing results with specific problems. On the selected articles a qualitative analysis was performed, using the methods of cross-case analysis and within-case analysis. Sixteen articles published between 1979 and 2003 were selected. Analysis led to the classification of four problems of unexpected findings: I. unexpected for professionals; II. unexpected for patients; III. uncertainty; IV. other difficult counselling issues. We conclude that currently the problems of unexpected findings relate only slightly to their unexpected character. Instead, the main problems of unexpected findings relate to uncertainty and other aspects which create difficult counselling issues. As such, unexpected findings can be distinguished only gradually from standard results. Before targeted testing can be applied it is necessary to establish exact criteria in order to discern unexpected findings from standard testing results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Viable trisomy 13 or 18 pregnancies may be supported by the presence of a diploid cell line, confined to the outer layer of the placenta (cytotrophoblast). To establish the presence of diploid cells ...we investigated five random biopsies from placentas of trisomy 13 (n = 8) and trisomy 18 cases (n = 6) of newborn infants and terminated pregnancies by means of fluorescence in situ hybridisation on interphase nuclei (n = 100). In 12 of these 14 placentas (including all five liveborns) 80% or more of the analysed nuclei showed three spots, suggestive of the presence of a full trisomy. In the other two placentas (both cases of trisomy 18) mosaicism was detected at most investigated sites. Thus, in contrast with earlier studies, these results show that a significant diploid cell line present in the placenta, confined to the trophoblast, is not a pre-requisite for intrauterine survival in the investigated cases.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Objective: The finding of full or mosaic trisomy 13 or 18 in first trimester chorionic villus sampling (CVS) may be a false-positive result. This report provides incidence and outcome information ...that may be helpful in counselling individual patients and in choosing adequate follow-up.
Study design: From a series of 6820 CVS cases, we retrospectively collected data on all patients (
n=51) with full (
n=30) or mosaic (
n=5) trisomy 18, and full (
n=13) or mosaic (
n=3) trisomy 13 in cytotrophoblast cells.
Results: Five false-positives were seen in patients with full trisomy 18 and three in the mosaic cases. One false-positive result was observed in full trisomy 13 and two false-positives in cases of mosaicism. No false-negative results were reported.
Conclusion: The diagnosis of trisomy 13 or 18 in cytotrophoblasts should be confirmed in other tissues, unless fetal abnormalities are seen at ultrasound. In case of mosaicism, follow-up amniocentesis is advised.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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