A new chromosome instability disorder (original) (raw)
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Gene Reports, 2017
Although the carriers with apparently balanced structural rearrangements have usually normal phenotype, phenotypical abnormalities can be seen in approximately 6% de novo cases. A number of different mechanisms are involved in the appearance of these phenotypic abnormalities, one of which is submicroscopic chromosomal imbalances at chromosomal breakpoints. Our goal was to unravel the possible submicroscopic chromosomal imbalances at chromosomal breakpoints by using array-CGH analysis in patients with apparently balanced structural rearrangements and to link these to the clinical findings. A total of nine patients with reciprocal translocation carriers (2 familial, 7 de novo) and six patients with inversion carriers (2 familial, 4 de novo) were included in this study. In order to evaluate the possible microdeletions and microduplications at the chromosomal breakpoints, DNA samples were isolated from the peripheral blood of the patients (and their parents) and investigated using array-CGH analysis. Array-CGH analysis revealed submicroscopic chromosomal imbalances at breakpoints in 3 of the 7 (43%) de novo reciprocal translocation carriers. Additionally, 1 out of 4 (25%) de novo inversion carriers were found to have a submicroscopic chromosomal imbalance in unrelated chromosome seen in cytogenetic analysis. Furthermore, no submicroscopic chromosomal imbalances were detected in either of the two familially transmitted reciprocal translocation carriers. Based on the results of both array-CGH analysis and conventional cytogenetic analysis, the karyotypes of the patients were designated as follows: 46
Chromosomal abnormalities -A review
With the discovery in 1956 that the correct chromosome number in humans is 46, the new era of clinical cytogenetics began its rapid growth. During the next few years, several major chromosomal syndromes with altered numbers of chromosomes were reported, i.e. Downsyndrome (trisomy21), turner syndrome (45,x) and klinefelter syndrome (47,xxy). Since then it has been well established that chromosome abnormalities contribute significantly to genetic disease resulting in reproductive loss, infertility, stillbirths, congenital anomalies, abnormal sexual developmentmental retardation and pathogenesis of malignancy.specific chromosome abnormalities have been associated with over 60 identifiable syndromes. They are present in at least 50% of spontaneous abortions, 6% of stillbirths, about 5% of couples with two or more miscarriages and approximately 0.5% of newborns. In women aged 35 or over, chromosome abnormalities are detected in about 2% of all pregnancies. Some of the abnormalities and t...
Chromosome Structural Alteration an Unusual Abnormality Characterizing Human Neoplasia
Novelty in Biomedicine, 2016
Background and Aim: Ring chromosomes are rare cytogenetic abnormalities that occur in less than 10% of hematopoietic malignancies. They are rare in blood disorder. The present review has focused on the ring chromosome associated with oncology malignancies. Materials and Methods: By reviewing the web-based search for all English scientific peer review articles published, was initiated using Medline/PubMed, Mitelman database ( http://cgap.nci.nih.gov/Chromosomes/Mitelman ), and other pertinent references on websites about ring chromosomes in Oncology. The software program as End Note was used to handle the proper references for instruction to author. Karyotype descriptions were cited according to ISCN. Conclusion: Ring chromosomes are rare chromosomal aberrations, almost many times are of de novo origin, presenting a different phenotype regarding the loss of genetic material. The karyotype represents the main analysis for detection of ring chromosomes, but other molecular technics are...
Cytogenetic effects of radiotherapy: Frequency and types of chromosome aberrations
International Journal of Radiation Oncology Biology Physics, 1990
The frequency and types of chromosome aberrations induced by ionizing radiation in cancer patients were evaluated in 24 cases studied just before and immediately after radiotherapy. The incidence of aberrant metaphases prior to treatment was 9.913% and increased significantly after treatment to 32.8%. The frequency of chromosome aberrations before radiotherapy was, with the exception of the cases of breast cancer and seminoma, significantly higher than that in our laboratory controls. A comparison of chromosome abnormalities observed before and after treatment indicated that dicentric translocations, rings, and reciprocal translocations increased by a factor of 23, 13, and 11, respectively, after radiotherapy. Ionizing radiation produces more asymmetrical than symmetrical chromosome aberrations and mlore two-break than one-break anomalies.
Fetal Diagnosis and Therapy, 2007
Objective: To determine an unusual complex chromosome rearrangement found in a man with oligospermia with a normal phenotype. Design: Case report with a review of the literature. Setting: Academic research environment. Patient(s): A man with oligospermia but otherwise apparently healthy. Intervention(s): Peripheral blood lymphocytes were used for karyotyping, and metaphases were analyzed by the fluorescence in situ hybridization (FISH) procedure. Further characterization of the karyotype was done by using multicolor banding (MCB) probes. Main Outcome Measure(s): Physical examination, semen analysis, GTG banding, FISH, MCB. Result(s): The semen analysis revealed oligospermia. The lymphocytic karyotype detected an unusual complex chromosome rearrangement involving chromosomes 2, 13, and 18 determined by banding cytogenetics. Karyotype was established as 46,XY,t(2;13;18)ins(2;13)(2qter/2p25.1::13q13/13q22::18q12.3/18qter;13pter/ 13q13::2p25/2pter;18pter/18q12.3::13q22/13qter) after MCB analysis. Conclusion(s): The association of an unusual complex chromosome rearrangement with three recurrent spontaneous abortions was reported. (Fertil Steril Ò 2009;92:391.e9-e12. Ó2009 by American Society for Reproductive Medicine.
International Journal of Molecular Sciences
Satellited non-acrocentric autosomal chromosomes (ps–qs-chromosomes) are the result of an interchange between sub- or telomeric regions of autosomes and the p arm of acrocentrics. The sequence homology at the rearrangement breakpoints appears to be, among others, the most frequent mechanism generating these variant chromosomes. The unbalanced carriers of this type of translocation may or may not display phenotypic abnormalities. With the aim to understand the causative mechanism, we revised all the ps–qs-chromosomes identified in five medical genetics laboratories, which used the same procedures for karyotype analysis, reporting 24 unrelated cases involving eight chromosomes. In conclusion, we observed three different scenarios: true translocation, benign variant and complex rearrangement. The detection of translocation partners is essential to evaluate possible euchromatic unbalances and to infer their effect on phenotype. Moreover, we emphasize the importance to perform both, mole...