Robertsonian translocations (RTs) are amongst the most common chromosome abnormalities, but being essentially balanced are not usually associated with phenotypic abnormality. Despite being dicentric, RTs are almost always transmitted stably through cell division without chromosome breakage. We have investigated spontaneous fission of der(13;15)(q10;q10) chromosomes in eight individuals from two unrelated kindreds with a view to assessing clinical significance and to seek an explanation for the peculiar heritable instability displayed by these chromosomes. In Family 1, fission products were observed in five members in three generations. The instability was observed in cells derived from chorionic villus and lymphocytes. In Family 2, the same phenomenon was observed in amniocytes from two separate pregnancies and maternal blood lymphocytes. Detailed FISH analysis of these RTs showed them to be dicentric with an unremarkable pericentromeric structure. Notably, combined immunofluoresence and FISH analysis showed the presence of the centromere-specific proteins CENP-A and CENP-E, consistent with functional dicentricity in >75% of cells analyzed. The fission products are, therefore, presumed to be the result of sporadic, bipolar kinetochore attachment, anaphase bridging with resultant inter-centromeric breakage in a small proportion of mitoses. None of the eight carriers shows phenotypic abnormality and therefore, for prenatal counseling purposes, there appears to be no increased specific risk associated with this phenomenon.
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http://dx.doi.org/10.1002/ajmg.a.30763 | DOI Listing |
Medicina (Kaunas)
October 2024
Laboratory of Human Genomics, University of Medicine and Pharmacy of Craiova, 200638 Craiova, Romania.
Recurrent pregnancy loss (RPL) is a multifactorial condition, encompassing genetic, anatomical, immunological, endocrine, as well as infectious and environmental factors; however, the etiology remains elusive in a substantial number of cases. Genetic factors linked to RPL include parental karyotype abnormalities (e.g.
View Article and Find Full Text PDFFertil Steril
November 2024
Instituto Valenciano de Infertilidad and Reproductive Medicine Associates Global Research Alliance, Reproductive Medicine Associates of New Jersey, Basking Ridge, New Jersey.
Objective: To determine whether translocation carriers have a reduced number of usable blastocysts compared with infertile controls.
Design: Retrospective cohort study.
Setting: Single infertility practice.
Am J Hum Genet
December 2024
Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Electronic address:
Taiwan J Obstet Gynecol
November 2024
Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.
Vavilovskii Zhurnal Genet Selektsii
October 2024
Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.
Metapolycentromeres consist of multiple sequential domains of centromeric chromatin associated with a centromere-specific variant of histone H3 (CENP-A), functioning collectively as a single centromere. To date, they have been revealed in nine flowering plant, five insect and six vertebrate species. In this paper, we focus on their structure and possible mechanisms of emergence and evolution.
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