The clinical application of a new, widely applicable method known as Karyomapping to carry out a total of 55 clinical cases of preimplantation genetic diagnosis (PGD) for single gene disorders is reported. Conventional polymerase chain reaction (PCR) testing was carried out in parallel to the new method for all cases. Clinical application of Karyomapping in this study resulted in three live births and nine clinical pregnancies out of 20 cases with a transfer. All in all, results presented in this study indicate that Karyomapping is a highly efficient, accurate and robust method for PGD of single gene disorders. Karyomapping can offer a more comprehensive assessment of the region of interest than conventional PCR analysis, allowing for more embryos to receive diagnosis (99.6% versus 96.8%), whereas its wide applicability reduces substantially the time that patients have to wait before starting their in vitro fertilization (IVF) cycle. Nonetheless, inclusion of elements of conventional PCR methodology, such as direct mutation detection, may be required in cases in which the gene of interest is in a region with reduced single nucleotide polymorphism (SNP) coverage (e.g. telomeric regions), when offering PGD for consanguineous couples, or in cases where no samples from additional family members are available.

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Preimplantation genetic diagnosis of aneuploidy (PGD-A) with comprehensive chromosome analysis has been known to improve pregnancy outcomes. Accuracy in detecting sex chromosomes becomes important when selecting against embryos at risk for sex-linked disorders. A total of 21,356 PGD-A cycles consisting of day-3 (cleavage) or day-5 (blastocyst) biopsies were received at the same laboratory for PGD-A via fluorescence in situ hybridization (FISH) or array comparative genome hybridization (aCGH) from multiple fertility centres. The misdiagnosis rates were 0.12% (Wilson 95% CI 0.05 to 0.25%) in day-3 FISH cycles, 0.48% (Wilson 95% CI 0.19 to 1.22%) in day-3 aCGH cycles and 0.0% (Wilson 95% CI 0 to 0.26) in day-5 aCGH cycles. Although rare, the likely causative biological event for true misdiagnosis is embryonic XX/XY mosaicism. Reanalysis of 1219 abnormal cleavage-stage research embryos revealed a 73% incidence of minor and major mosaicism. Only four (0.3%) embryos were found to be diploid and contained XX and XY cells that could potentially account for the misdiagnosis of sex. Our investigation identified errors leading to misdiagnosis and their attribution to specific events during PGD-A testing. The reported misdiagnosis rates suggest that PGD-A for sex determination is highly accurate, particularly when using aCGH applied to blastocyst biopsies.

The aim of this study was to evaluate if clinical outcomes differ between day 5 blastocyst stage vitrified embryos thawed on the day prior to versus the day of transfer.MATERIALS AND METHODS: Design: Retrospective study.Setting: Academic fertility center.Interventions: Blastocysts vitrified and thawed the day prior to transfer (Group 1) were compared to those thawed the day of transfer (Group 2). All embryos were vitrified on the cryolock device and all patients underwent endometrial priming. Pregnancies were initially detected by serum b-human chorionic gonadotropin (hCG) concentrations. Clinical pregnancy and implantation were confirmed by transvaginal ultrasound (US). Exclusion criteria included: donor oocyte, pre-implantation genetic testing, and gestational carrier cycles, as well as cycles that included embryos imported from different centers and cycles with combined day 5 (D5) and day 6 (D6) frozen embryo transfers.Outcome Measures: Positive pregnancy test (serum b-hCG concentration >6 IU/L) per cryothaw cycle, clinical pregnancy (CPR) and implantation rates (number of sacs observed on US over the number of embryos transferred).Statistics: X 2 -square and t-test were used as appropriate. P<0.05 was considered statistically significant.RESULT(S): A total of 112 thawed blastocysts (88 D5, 24 D6) from 94 patients were included in the analysis. Patient characteristics did not differ between the 2 groups of embryos (Table 1). When all blastocyst stage embryos (D5 and D6) were compared between the Group 1 and Group 2, positive pregnancy test (61.7% vs 70.2, p¼0.51, respectively), CPR (61.7% vs 62.2%, p¼1.00, respectively) and, implantation (85.0% vs 82.4%, p¼0.76, respectively) rates did not differ. When the analysis was restricted to D5 embryos, which were the blastocysts affected by the intervention implemented, positive pregnancy test, CPR and implantation rates were similar amongst the groups (Chart 1). CONCLUSION(S): According to our findings, thawing D5 blastocysts the day prior to transfer does not impact CPR or implantation rates, thus allowing embryologists some flexibility to the timing of D5 embryo thaw.FINANCIAL SUPPORT: none.

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