Browsing by Author "Teearu, Katre"

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Enneaegne ovariaalpuudulikkus ja selle geneetilised põhjused
(Tartu Ülikool, 2014-06-12) Teearu, Katre; Kurg, Ants, juhendaja; Tartu Ülikool. Loodus- ja tehnoloogiateaduskond; Tartu Ülikool. Molekulaar- ja rakubioloogia instituut
Genetic abnormalities in premature ovarian failure patients
(Tartu Ülikool, 2016) Teearu, Katre; Tartu Ülikool. Loodus- ja tehnoloogiateaduskond; Tartu Ülikool. Molekulaar- ja rakubioloogia instituut
Somatic mosaicism, defined as the presence of different cell populations with distinct genotypes within one individual, caused by post-zygotic errors, has long been considered as a source for human genetic variation within and between individuals. It is also plausible that the presence of large structural mosaic events could have important implications for human diseases. In this study, we provide a genome-wide survey of genetic variation in premature ovarian failure (POF) patients by analyzing SNP array data with a novel algorithmic method that deciphers mosaic structural alterations. We found mosaic aberrations in 8.2% of samples, including 23 mosaic copy number variation (CNV) regions, one mosaic X monosomy and 24 (larger than 1 Mb) mosaic uniparental disomy (UPD) events. In addition, we were able to investigate 23 novel CNVs among patients.
In vitro fertilization does not increase the incidence of de novo copy number alterations in fetal and placental lineages
(Nature Medicine, 2019-11-04) Esteki, Masoud Zamani; Viltrop, Triin; Tšuiko, Olga; Tiirats, Airi; Koel, Mariann; Nõukas, Margit; Žilina, Olga; Teearu, Katre; Marjonen, Heidi; Kahila, Hanna; Meekels, Jeroen; Söderström-Anttila, Viveca; Suikkari, Anne-Maria; Tiitinen, Aila; Mägi, Reedik; Kõks, Sulev; Kaminen-Ahola, Nina; Kurg, Ants; Voet, Thierry; Vermeesch, Joris Robert; Salumets, Andres
Although chromosomal instability (CIN) is a common phenomenon in cleavage-stage embryogenesis following in vitro fertilization (IVF)1,2,3, its rate in naturally conceived human embryos is unknown. CIN leads to mosaic embryos that contain a combination of genetically normal and abnormal cells, and is significantly higher in in vitro-produced preimplantation embryos as compared to in vivo-conceived preimplantation embryos4. Even though embryos with CIN-derived complex aneuploidies may arrest between the cleavage and blastocyst stages of embryogenesis5,6, a high number of embryos containing abnormal cells can pass this strong selection barrier7,8. However, neither the prevalence nor extent of CIN during prenatal development and at birth, following IVF treatment, is well understood. Here we profiled the genomic landscape of fetal and placental tissues postpartum from both IVF and naturally conceived children, to investigate the prevalence and persistence of large genetic aberrations that probably arose from IVF-related CIN. We demonstrate that CIN is not preserved at later stages of prenatal development, and that de novo numerical aberrations or large structural DNA imbalances occur at similar rates in IVF and naturally conceived live-born neonates. Our findings affirm that human IVF treatment has no detrimental effect on the chromosomal constitution of fetal and placental lineages.
Karyotype of the blastocoel fluid demonstrates low concordance with both trophectoderm and inner cell mass
(2018-06) Tšuiko, Olga; Zhigalina, Daria I.; Jatsenko, Tatjana; Skryabin, Nikolay A.; Kanbekova, Olga R.; Artyukhova, Victoria G.; Svetlakov, Anatoly V.; Teearu, Katre; Trošin, Aleksander; Salumets, Andres; Kurg, Ants; Lebedev, Igor N.
Objective To compare the genomic profiles of blastocoel fluid (BF), inner cell mass (ICM), and trophectoderm (TE) cells derived from the same blastocyst. Design Prospective study. Setting Academic and in vitro fertilization units. Patient(s) Sixteen donated cryopreserved embryos at blastocyst stage. Intervention(s) BF, TE, and ICM cells were retrieved from each blastocyst for chromosome analysis by means of next-generation sequencing (NGS). Main Outcome Measure(s) Aneuploidy screening and assessment of mosaicism in BF, TE and ICM samples with subsequent comparison of genomic profiles between the three blastocyst compartments. Result(s) Out of 16 blastocysts, 10 BF samples and 14 TE and ICM samples provided reliable NGS data for comprehensive chromosome analysis. Only 40.0% of BF-DNA karyotypes were fully concordant with TE or ICM, compared with 85.7% concordance between TE and ICM. In addition, BF-DNA was burdened with mosaic aneuploidies and the total number of affected chromosomes in BF was significantly higher compared with the TE and ICM. Conclusion(s) BF-DNA can be successfully amplified and subjected to NGS, but owing to increased discordance with ICM and TE, BF does not adequately represent the status of the rest of the embryo. To overcome biologic and technical challenges associated with BF sampling and processing, blastocentesis would require improvement in both laboratory protocols and aneuploidy calling algorithms. Therefore, TE biopsy remains the most effective way to predict embryonic karyotype, and the use of BF as a single source of DNA for preimplantation genetic screening is not yet advised.