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Ring chromosome

About: Ring chromosome is a research topic. Over the lifetime, 1546 publications have been published within this topic receiving 31061 citations. The topic is also known as: supernumerary circular chromosome.


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Journal ArticleDOI
TL;DR: Cytogenetic and molecular techniques were employed to determine the origin of marker chromosomes in five patients with mosaic 45,X karyotypes, showing markers to be derived from the X chromosome in three female patients and from the Y chromosome in one female and one male.
Abstract: Cytogenetic and molecular techniques were employed to determine the origin of marker chromosomes in five patients with mosaic 45,X karyotypes. The markers were shown to be derived from the X chromosome in three female patients and from the Y chromosome in one female and one male. One of the female patients, with a very small, X-derived ring chromosome, had additional phenotypic abnormalities not typically associated with Turner syndrome. In this patient, both the ring and the normal X chromosomes replicated early; perhaps the unusual phenotype is the result of both chromosomes remaining transcriptionally active. These studies illustrate the power of resolution and utility of combined cytogenetic and molecular approaches to some clinical cases.

41 citations

Journal ArticleDOI
TL;DR: The most prominent karyotypic feature was the occurrence of deletions and losses of whole chromosome copies indicating the importance of tumor suppressor genes in transitional cell carcinoma pathogenesis.
Abstract: Chromosome analysis by G-banding, spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) was per formed on 24 short-term cultured transitional cell bladder carcinomas and 5 cell lines established from bladder carcinomas. Except for one tumor with an apparently normal chromosomal constitution, clonal chromosome abnormalities were detected in all examined cases by the combined approach. The application of SKY and FISH techniques improved the karyotypic descriptions, originally based on C-banding only, by identifying 32 additional numerical changes, by establishing the chromosomal origin of 27 markers and 2 ring chromosomes, by redefining 53 aberrations and by detecting 15 hidden chromosomal rearrangements. No recurrent translocation, however, was detected. The most prominent: karyotypic feature was thus the occurrence of deletions and losses of whole chromosome copies indicating the importance of tumor suppressor genes in transitional cell carcinoma pathogenesis. Invasive carcinomas were karyotypically more complex than were low grade superficial tumors. Specific leases of material from chromosome 9 and from chromosome arms I Ip and 8p, and gains of 8q and Iq seem to be early changes appearing in superficial tumors, whereas losses from 4p and 17p and the formation of an isochromosome for 5p were associated with more aggressive tumor phenotypes. (Less)

41 citations

Journal ArticleDOI
01 Jul 1995-Genetics
TL;DR: With the exception of low mutation rate, the observed phenomena are consistent with the activity of a Ds-like element, however, it is not clear whether such an element was of wheat or rye origin.
Abstract: During the development of disomic additions of rye (Secale cereale L.) chromosomes to wheat (Triticum aestivum L.), two reverse tandem duplications on wheat chromosomes 3D and 4A were isolated. By virtue of their meiotic pairing, the reverse tandem duplications initiated the chromatid type of the breakage-fusion-bridge (BFB) cycle. This BFB cycle continued through pollen mitoses and in the early endosperm divisions, but no clear evidence of its presence in embryo mitoses was found. The chromosome type of BFB cycle was initiated by fusion of two broken chromosome ends resulting in a dicentric or a ring chromosome. Chromosome type BFB cycles were detected in embryo mitoses and in root tips, but they did not persist until the next meiosis and were not transmitted to the progeny. Active BFB cycles induced breakage of other wheat chromosomes that resulted in additional reverse tandem duplications and dicentric and ring chromosomes. Four loci, on chromosome arms 2BS, 3DS, 4AL, and most likely on 7DL, were particularly susceptible to breakage. The BFB cycles produced high frequency of variegation for pigmentation of the aleurone layer of kernels and somatic chimeras for a morphological marker. With the exception of low mutation rate, the observed phenomena are consistent with the activity of a Ds-like element. However, it is not clear whether such an element, if indeed present, was of wheat or rye origin.

41 citations

Journal ArticleDOI
TL;DR: A novel origin for supernumerary small rings is proposed: that they may originate from incompletely digested superfluous (haploid) pronuclei.
Abstract: Seven supernumerary small ring marker autosomes were studied The pantelomere probe (Oncor) in conjunction with scoring for dicentric rings was used to confirm ring morphology The small rings were identified mainly by FISH with chromosome probe arrays (Cytocell) containing representations from all 24 chromosomes and the rings were derived from chromosomes 7, 8 (three cases), 11, 12, and 14 The effectiveness of the array methodology in identifying markers was tested Microsatellite DNA data showed biparental disomy (BPD) was present for the rings from chromosomes 7 and 14 thereby excluding UPD, both were de novo but the ring 14 was of paternal origin The literature on supernumerary small ring autosomes was reviewed excluding chromosome 15 The grade and distribution of mosaicism was invoked as the major determinant of the differences in phenotype and, in addition, variation was attributed to the possibility of different contributions from each chromosome arm There are 88 published supernumerary small ring cases in total, with phenotypic data attributable to the respective rings in 77 cases and all chromosomes being represented except chromosome 17 Of the prenatally ascertained cases, where there was adequate phenotypic data, 30% had an abnormal phenotype attributable to the ring, and there were 44% familial cases in this group Of the postnatally ascertained small rings, 75% had an abnormal phenotype attributable to the ring and there were 13% familial cases This higher abnormality rate is concordant with the considerable ascertainment bias of this latter group and the prenatal data are recommended for genetic counseling Although data are small there were some differences between the rings derived from different chromosomes Chromosomes 3 and 8 demonstrate the extremes Of the supernumerary small r(8) cases reviewed including the three presently described, 8/11 had an abnormal phenotype attributable to the marker but of the small r(3) cases, only 1/6 had an abnormal phenotype Two of the present r(8) were studied with the GATA4 probe at 8p231 The r(8) in case 2 (patient moderately retarded) was comprised mostly of an intact 8p whereas the larger r(8) in case 3 (normal phenotype) was missing 8p231 --> pter and had more of 8q contributing to the ring In other supernumerary rings postnatally ascertained, there is mostly insufficient data but there is an abnormal phenotype in 8/11 cases with multiple small rings, in 5/6 cases with r(20), and in 5/10 with r(1) A novel origin for supernumerary small rings is proposed: that they may originate from incompletely digested superfluous (haploid) pronuclei The small rings presumptively so formed may occasionally be transfected into the zygote nucleus The high proportion ( approximately 125%) of cases with multiple supernumerary small rings almost always of different centromeric origin is consistent with this concept

40 citations

Journal ArticleDOI
Adewale Adeyinka1, S Kytola1, Fredrik Mertens1, Nikos Pandis1, C Larsson1 
TL;DR: The present study underscores the need to combine conventional chromosome banding and molecular cytogenetic techniques in the cytogenetics analysis of solid tumors.
Abstract: Three primary breast tumors and their lymph node metastases were characterized by G-banding, spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH) In each case, the karyotypic abnormalities detected were similar in the primary tumor and its matched metastasis Two of the pairs had near-diploid karyotypes with three to four chromosomal aberrations, whereas the third pair had a near-pentaploid chromosome content and many marker chromosomes in the primary tumor and a near-tetraploid chromosome number with almost the same marker chromosomes in the metastasis SKY and FISH confirmed the karyotypic similarities between the primary tumors and their metastases and, in addition, improved the identification and characterization of marker chromosomes One of the tumor pairs with near-diploid karyotypes had gain of 8q, 16q, and 17q, whereas the other had gain of 1q and chromosome 8 material in the form of ring chromosomes The third pair had more complex chromosomal translocations and numerical changes resulting in net gain of material from chromosomes X, 1, 2, 6, 7, 14, 16, 19, and 20, and chromosome arms 8q and 11q, as well as net loss of material from chromosomes 3, 13, 18, 21, and 22 The present study underscores the need to combine conventional chromosome banding and molecular cytogenetic techniques in the cytogenetic analysis of solid tumors

40 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202310
202221
202123
202019
201919
201836