Journal ArticleDOI
Ring chromosome 21 in healthy persons: different consequencies in females and in males
TLDR
A stable ring chromosome 21 was found in an azoospermic man with an otherwise normal phenotype, and eight healthy females with r(21) were fertile, however, they were at risk for Down syndrome and spontaneous abortions.Abstract:
A stable ring chromosome 21 was found in an azoospermic man with an otherwise normal phenotype. Meiotic studies in another known azoospermic male with r(21) had indicated that breakdown of spermatogenesis resulted from pairing failure of chromosome 21, followed by degenerative changes in the chromosomes, before the cells had completed the first meiotic division. While primary sterility was a constant feature in the three adult males, eight healthy females with r(21) were fertile. However, they were at risk for Down syndrome and spontaneous abortions.read more
Citations
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Journal ArticleDOI
Inherited ring chromosomes: an analysis of published cases.
TL;DR: Out of 30 transmitted rings, there were 9 where parent and child were both mosaics, suggesting an inherited instability of the chromosome involved leading to de novo re-formation of the ring in the second generation.
Journal Article
p53 controls low DNA damage-dependent premeiotic checkpoint and facilitates DNA repair during spermatogenesis.
TL;DR: It is reported that p53 knockout mice exhibit significantly less mature motile spermatozoa than their p53(+/+) counterparts, and p53 provides another level of stringency in addition to other spermatogenic "quality control" mechanisms.
Journal Article
No significant effect of monosomy for distal 21q22.3 on the Down syndrome phenotype in "mirror" duplications of chromosome 21.
Constantinos Pangalos,D Théophile,P M Sinet,A Marks,D Stamboulieh-Abazis,Zoubida Chettouh,Marguerite Prieur,C Verellen,M O Rethoré,Jérôme Lejeune +9 more
TL;DR: Three Down syndrome patients for whom karyotypic analysis showed a "mirror" (reverse tandem) duplication of chromosome 21 were studied, suggesting that the reverse tandem chromosomes did not result from a telomeric fusion between chromosomes 21 but from a translocation between sister chromatids.
Journal ArticleDOI
Ring chromosomes: from formation to clinical potential.
TL;DR: Ring chromosomes are circular DNA molecules, which occur rarely in eukaryotic nuclear genomes, and potential clinical applications of artificially created RCs for large-scale chromosome rearrangement treatment are examined.
Journal ArticleDOI
Molecular characterisation of partial chromosome 21 aneuploidies by fluorescent PCR.
Rebeca Valero,Gemma Marfany,Rosario Gil-Benso,Maria de los Angeles Ibáñez,Isidora López-Pajares,Félix Prieto,Gaspar Rullan,Enric Sarret,Roser Gonzàlez-Duarte +8 more
TL;DR: The parental origin of the aneuploidy was assigned for each case, which allowed us to conclude that two of the monosomic cases originated from de novo chromosomal rearrangements.
References
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Journal ArticleDOI
The Role of X-Chromosome Inactivation during Spermatogenesis
TL;DR: X-chromosome inactivation during spermatogenesis is proposed as the ideal system for studies of genetic control at the chromosomal level.
Journal ArticleDOI
Meiotic studies of translocations causing male sterility in the mouse
Jiri Forejt,Gregorová S +1 more
TL;DR: The present observations lend indirect support to the working hypothesis, the assumption that interference with X-chromosome inactivation is a possible cause of spermatogenic breakdown in carriers of various male-sterile chromosomal transloations.
Journal ArticleDOI
Translocations, the predominant cause of total sterility in sons of mice treated with mutagens.
TL;DR: It is proposed that many cases of induced F(1) male sterility may be the result of position effects produced when paracentromeric regions are translocated to euchromatic regions of certain other chromosomes.
Journal ArticleDOI
Acute megakaryoblastic leukaemia associated with intrinsic platelet dysfunction and constitutional ring 21 chromosome in a young boy
Ching-Hon Pui,Dorothy L. Williams,Victoria D. Scarborough,Carl W. Jackson,Robert A. Price,Sharon B. Murphy +5 more
TL;DR: A 3‐year‐old boy with pancytopenia and a paucity of circulating blast cells was found to have acute megakaryoblastic leukaemia, and the finding of a constitutional chromosomal defect, a ring No. 21 chromosome, in addition to an abnormal malignant stem line is believed to be the first reported instance of aconstitutional r(21) chromosome associated with acuteLeukaemia.