Publications by authors named "Anna A Pendina"

Article Synopsis
  • Preimplantation genetic testing for aneuploidies (PGT-A) is commonly used in assisted reproduction, but surprisingly, it doesn't significantly enhance clinical outcomes due to discrepancies between PGT-A results and the actual chromosomal makeup of blastocysts.
  • A study analyzed 23 blastocysts from 17 couples, where PGT-A revealed chromosomal imbalances, by re-biopsying the trophectoderm (TE) and separately examining the inner cell mass (ICM).
  • Out of the 23 cases, only 8 had consistent PGT-A results with re-biopsy findings, while 4 showed partial discordance, indicating the complexity of accurately assessing chromosomal status in embryos.
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Predicting the clinical outcomes of intracytoplasmic sperm injection (ICSI) cycles that use the testicular spermatozoa of azoospermic patients presents a challenge. Thus, the development of additional approaches to assessing the competence of a testicular-sperm-derived embryo without causing damage to gametes or the embryo is necessary. One of the key parameters in determining such developmental competence is telomere length (TL).

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We report on the case of prenatal detection of trisomy 2 in placental biopsy and further algorithm of genetic counseling and testing. A 29-year-old woman with first-trimester biochemical markers refused chorionic villus sampling and preferred targeted non-invasive prenatal testing (NIPT), which showed low risk for aneuploidies 13, 18, 21, and X. A series of ultrasound examinations revealed increased chorion thickness at 13/14 weeks of gestation and fetal growth retardation, a hyperechoic bowel, challenging visualization of the kidneys, dolichocephaly, ventriculomegaly, increase in placental thickness, and pronounced oligohydramnios at 16/17 weeks of gestation.

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Uterine leiomyomas (ULs), frequent benign tumours of the female reproductive tract, are associated with a range of symptoms and significant morbidity. Despite extensive research, there is no consensus on essential points of UL initiation and development. The main reason for this is a pronounced inter- and intratumoral heterogeneity resulting from diverse and complicated mechanisms underlying UL pathobiology.

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Article Synopsis
  • A comparative cytogenomic analysis of cultured and uncultured uterine leiomyoma (UL) samples revealed significant chromosomal abnormalities, including complex rearrangements and mutations in some cases.
  • The study found that both cultured and uncultured UL samples exhibited shorter telomeres compared to normal myometrium, which may be linked to the observed chromosomal rearrangements.
  • The results highlighted that ULs present both inter- and intratumor genetic heterogeneity, with unique clonal spectra for each tumor, while the frequencies of abnormal cells can vary between cultured and uncultured samples.
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Article Synopsis
  • The study explores telomere length (TL) in chorionic cytotrophoblast cells from both normal and abnormal first trimester pregnancies, finding no significant differences in TL for karyotypically normal samples between miscarriages and ongoing pregnancies.
  • Notably, karyotypically abnormal samples showed significantly higher TLs in ongoing pregnancies compared to miscarriages, and also had higher TLs compared to karyotypically normal samples in ongoing pregnancies.
  • The research suggests that interchromatid TL asymmetry and its association with certain methylation patterns are related to the developmental processes of chorionic cytotrophoblast, indicating that TL variations are inherited rather than influenced by telomere elongation mechanisms.
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Article Synopsis
  • The study investigates how telomere length (TL) affects human lifespan, focusing on its determination in triploid zygotes from both maternal and paternal chromosomes.
  • Using Q-FISH, researchers analyzed TL in 28 human triploid zygotes, finding that paternal chromosomes exhibited longer mean relative TLs compared to maternal ones, indicating a possible "imprinting" effect.
  • Despite the differences in TL based on parental origin, age or quality of sperm did not influence TL, highlighting the importance of heredity over environmental factors in determining TL in zygotes.
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In the present study, we aimed to check whether uterine leiomyomas (ULs) with an apparently normal karyotype in vitro comprise "hidden" cell subpopulations with numerical chromosome abnormalities (heteroploid cells). A total of 32 ULs obtained from 32 patients were analyzed in the study. Each UL was sampled for in vivo and in vitro cytogenetic studies.

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We studied the impact of age and the serum anti-Müllerian hormone (AMH)/follicle-stimulating hormone (FSH) levels on the number of cumulus-oocyte complexes (COCs) retrieved from female reciprocal and Robertsonian translocation carriers after controlled ovarian hyperstimulation (COH). The number of COCs retrieved after COH was retrospectively analyzed in female translocation carriers and 46,XX partners of male translocation carriers from 100 couples. The median number of COCs varied from nine to 16 and did not differ among subgroups of women categorized by age, presence and type of a translocation.

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Article Synopsis
  • Epigenetic modifications, specifically DNA methylation, play a critical role in regulating the mammalian genome and its adaptability throughout development influenced by both genetic programming and environmental factors.
  • Changes in DNA methylation can lead to genetic dysfunction and various diseases, especially when exacerbated by harmful environmental exposures such as pollutants and drugs.
  • This review focuses on the oxidized form of cytosine (5-hydroxymethylcytosine, or 5hmC), its stability, and its relevance in response to environmental factors, detailing the molecular mechanisms behind how these exposures impact hydroxymethylation patterns in the genome.
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We report on the phenotype and the reproductive history of an adult female patient with an unbalanced karyotype: 8p23 and 18p11.3 terminal deletions and 8p22 duplication. The indication for karyotyping of the 28-year-old patient was a structural rearrangement in her miscarriage specimen: 45,ХХ,der(8;18)t(8;18)(p23;p11.

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Article Synopsis
  • - The study investigated genetic variants responsible for monogenic diabetes in 60 Russian children diagnosed with non-type 1 diabetes before age 18, utilizing whole-exome sequencing across 35 genes associated with MODY and neonatal diabetes.
  • - Researchers identified 38 genetic variants in 55% of patients, with a significant majority linked to MODY-related genes, particularly GCK, while a smaller group had variants in MODY-unrelated genes.
  • - The findings suggest a high occurrence of various genetic variants, emphasizing the importance of starting monogenic diabetes diagnostics in Russian children with GCK testing, while also highlighting the effectiveness of whole-exome sequencing for identifying rare variants.
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In the present review, we focus on the phenomenon of chromothripsis, a new type of complex chromosomal rearrangements. We discuss the challenges of chromothripsis detection and its distinction from other chromoanagenesis events. Along with already known causes and mechanisms, we introduce aberrant epigenetic regulation as a possible pathway to chromothripsis.

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Article Synopsis
  • 5-hydroxymethylcytosine (5hmC) is a modified form of 5-methylcytosine (5mC) and exhibits significant variations between DNA strands and cells in mammals.* -
  • Research revealed different patterns of 5hmC distribution in noncultured human cells, observing three types of chromosomes based on 5hmC accumulation: hydroxymethylated, hemihydroxymethylated, and nonhydroxymethylated.* -
  • Unlike the variable 5hmC distribution, the locations of 5mC were consistent across chromosomes, indicating a stable methylation pattern particularly in certain heterochromatic regions of embryonic lung cells.*
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Article Synopsis
  • The study analyzed DNA hydroxymethylation and methylation in human testicular cells and sperm from azoospermic patients and sperm donors, finding that while methylation was consistent throughout spermatogenesis, hydroxymethylation varied and was mostly low in sperm samples.
  • High levels of hydroxymethylcytosine were primarily found in a small population of sperm cells, indicating that variations in hydroxymethylation patterns are likely not genetically programmed but may indicate abnormalities.
  • Increased levels of hydroxymethylated sperm correlated negatively with markers of good semen quality and positively with sperm DNA fragmentation, suggesting that hydroxymethylation could serve as a new indicator for assessing sperm quality in infertile couples.
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Aims: To study the possible association of catechol-O-methyltransferase ( Val158Met polymorphism with multiple and solitary uterine leiomyomas (ULs) and to check whether the Val/Val genotype is associated with exon 2 mutations in fibroids.

Methods: The Val158Met allele and genotype frequencies were compared between age-matched women with ULs (n=104) and controls (n=59). Patients with UL were subcategorised by diagnosis of solitary (n=59) or multiple (n=45) fibroids and by the presence of somatic exon 2 mutations in at least one fibroid (n=32) or in neither fibroid (n=26).

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Pre-eclampsia (PE) is a complication of pregnancy that affects 5‑8% of women after 20 weeks of gestation. It is usually diagnosed based on the de novo onset of hypertension and proteinuria. Preexisting hypertension in women developing PE, also known as superimposed PE on chronic hypertension (SPE), leads to elevated risk of maternal and fetal mortality.

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Article Synopsis
  • The study examines how the patterns of 5-hydroxymethylcytosine (5hmC) change in human preimplantation embryos during the process of DNA methylation reprogramming.
  • It reveals that in zygotes, 5hmC is more concentrated in the paternal chromosome set and is specifically localized to certain regions, known as R-bands, while being sparse in the maternal set.
  • As embryonic cleavage occurs, there is a loss of 5hmC and its distribution becomes less symmetrical among sister chromatids, indicating dynamic changes in hydroxymethylation patterns throughout early development.
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Article Synopsis
  • The study compares karyotype abnormalities in first trimester miscarriages among women under and over 35 years, distinguishing between those who conceived naturally (NC) and through in vitro fertilization (IVF).
  • A total of 499 miscarriage karyotypes were analyzed, revealing no significant difference in abnormal karyotype incidence between NC and IVF patients in either age group, although younger IVF patients had a lower incidence of abnormalities.
  • The findings suggest that IVF does not increase the risk of miscarriage due to abnormal karyotypes, indicating that early pregnancy loss in younger IVF patients is usually due to non-cytogenetic factors rather than chromosomal issues.
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