Chromosome topology in normal and aneuploid blastomeres from human embryos

Diblík, Jan; Maçek, Milan; Magli, M. Cristina; Krejčí, Roman; Gianaroli, Luca

doi:10.1002/pd.1834

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…Furthermore, as demonstrated by the goodness of fit test, aneuploidies were not randomly distributed within the same oocyte, suggesting that aneuploidies are probably caused by a dysfunction of the meiotic spindle rather than by the shape and features of the chromosomes. The physiological implications of this condition are unknown but other studies in sperm cells and in preimplantation embryos have reported that chromosomes have a defined, non-random localization within the nucleus, suggesting that the organization of the genome could be functionally important (Foster et al ., 2005; Mudrak et al ., 2005; Diblik et al ., 2007). …”

Section: Discussionmentioning

confidence: 99%

Predicting aneuploidy in human oocytes: key factors which affect the meiotic process

Gianaroli¹,

Magli²,

Cavallini³

et al. 2010

Human Reproduction

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BACKGROUNDTo estimate the incidence of aneuploidy in relation to patients' characteristics, the type of hormonal stimulation and their response to induction of multiple follicular growth, 4163 first polar bodies (PB1s) were analyzed.METHODSFive hundred and forty four infertile couples underwent 706 assisted conception cycles (640 with poor prognosis indications and 66 controls) in which chromosomal analysis of PB1 for the chromosomes 13, 15, 16, 18, 21 and 22 was performed. Results were evaluated in a multivariate analysis.RESULTSThe proportion of normal oocytes was directly correlated (P < 0.01) with (i) the number of mature oocytes and (ii) the establishment of a clinical pregnancy; and inversely correlated (P < 0.01) with (i) female age, (ii) causes of female infertility (endometriosis, abortions, ovulatory factor), (iii) poor prognosis indications (female age, number of previous cycles, multiple poor prognosis indications), (iv) number of FSH units per oocyte and (v) number of FSH units per metaphase II oocyte. There was a weak significance of frequency (P < 0.05) between type of abnormality (originated by chromatid predivision, chromosome non-disjunction or combined mechanisms in the same oocyte) and groups of the studied variables, rather than to a specific abnormality or a specific chromosome.CONCLUSIONSThe type of infertility had a significant effect on errors derived from the first meiotic division, whose incidence was significantly higher in the presence of endometriosis or of an ovulatory factor, and in women that experienced repeated abortions. Each aneuploidy event was found to be dependent not on a specific variable, but on groups of variables. In addition, the tendency of chromosomal abnormalities to occur simultaneously implies that the deriving aneuploidies can be of any type.

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Section: Discussionmentioning

confidence: 99%

Predicting aneuploidy in human oocytes: key factors which affect the meiotic process

Gianaroli¹,

Magli²,

Cavallini³

et al. 2010

Human Reproduction

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“…We are aware of only three previous studies on nuclear organisation in human embryos: two of the three (Diblik et al 2007;McKenzie et al 2004) showed no evidence of a chromocentre, whereas the other study (Finch et al 2008a) indicated its presence. The dynamics of nuclear organisation and its relationship to gene expression in the early human embryo clearly warrant further investigation, in particular if there are patterns that may indicate future development potential.…”

Section: Discussionmentioning

confidence: 82%

Twenty-four chromosome FISH in human IVF embryos reveals patterns of post-zygotic chromosome segregation and nuclear organisation

Ioannou

Fonseka

Meershoek³

et al. 2012

Chromosome Res

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Fluorescence in situ hybridisation (FISH) was first applied on in vitro fertilisation (IVF) embryos for the preimplantation genetic diagnosis of sex, then chromosome translocations and later for chromosome copy number (PGS). Because of the controversy surrounding PGS diagnostically, it has been replaced by array-based approaches; however, FISH remains a powerful tool for investigating mechanisms of both post-zygotic segregation error and nuclear organisation, especially if most or all of the chromosomes in the karyotype can be analysed. The purpose of this study was to develop and apply a 24 chromosome FISH assay to investigate chromosome-specific rates of gain and loss, nuclear organisation patterns and the veracity of the original PGS result in days 5-6 human embryos. Analysis of 17 embryos by this newly developed approach gave strong signals for all chromosomes; it revealed chromosome copy number for each human chromosome per cell for each embryo and the nuclear address of the (mostly centromeric) loci probed. As all embryos were surplus to IVF requirements for both transfer and freezing (and many had an abnormal PGS indication) expected high levels of chromosome abnormalities were seen and no single nucleus displayed a normal complement; all were mosaic. Certain patterns emerged, however, namely that chromosome loss was more common than gain and apparent mitotic non-disjunction. Moreover, the centromeric probes tended preferentially to occupy the nuclear centre. Where we had a prior day 3 biopsy PGS result, it was confirmed, in part, by 24 colour FISH in most but not all cases.

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