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At least 829 records · Page 46Linked to original sources
PubMed2000

Specific patterns of chromosomal abnormalities are associated with RER status in sporadic colorectal cancer.

Current opinion of the genetic events driving colorectal tumourigenesis focuses on genomic instability. At least two apparently independent mechanisms are recognized, microsatellite instability and chromosomal instability. The genetic defects underlying each type of instability are only partially understood and controversy remains as to the role of p53 in the generation of chromosomal defects in colorectal cancer. This study sought to clarify the relationships between chromosomal abnormalities and defects of both p53 and mismatch repair. Extensive chromosomal analysis was undertaken, using flow cytometry and comparative genomic hybridization, of a series of sporadic colorectal cancers which had been grown to early passage as subcutaneous xenografts in SCID mice. Overall levels of chromosomal defects were observed to be low in RER+ cancers compared with RER- and distinctive patterns of chromosomal anomalies were found to be associated with both the RER+ and RER- phenotype. No particular level or pattern of chromosomal anomalies appeared to be associated with p53 status, supporting recent observations that abnormal p53 function is not sufficient to cause chromosomal anomalies in colorectal tumours.

Adult↗
PubMed1992

A new nonrandom chromosomal abnormality, t(2;16)(p11.2;p11.2), possibly associated with poor outcome in childhood acute lymphoblastic leukemia.

We report a new, nonrandom t(2;16)(p11.2;p11.2) in childhood acute lymphoblastic leukemia (ALL). Three of 292 patients with childhood ALL studied at Indiana University Medical Center had this translocation. All three had additional chromosomal abnormalities at diagnosis and were classified as having low hyperdiploidy (47-49 chromosomes) with structural abnormalities. The patients, two boys and one girl, ranged in age from 3 to 13 years. Peripheral white blood cells (WBC) counts ranged from 1.8 to 107.4 x 10(9)/L, all were classified as French-American-British (FAB) type L1, and all had B-lineage ALL. Because all three patients have relapsed after first remissions of 2 years 8 months to 6 years, the t(2;16) may indicate a poor prognosis and more aggressive treatment may be indicated for such patients. Because this translocation was the sole abnormality in one clone of patient 2 at relapse, it may be considered the primary abnormality. Therefore, it may also be the primary abnormality in the other two patients, and the genes involved in the breakpoints may be important in leukemogenesis.

Adolescent↗
PubMed1976

Acne in retarded boy with autosomal chromosomal abnormality.

The frequency of acne appears to be increased in boys and men of the XYY genotype. This report describes severe acne in a retarded man in whom chromosomal analysis with differential banding suggested duplication of the distal portion of the long arm of a number 13 chromosome, a partial trisomy 13. In addition to retardation and seizures, his malformations, which included narrowed temples, ear anomalies, hexadactyly, and hernias, were consistent with those reported previously in patients with partial trisomy for the distal segment of chromosome 13. This patient and one recently reported retarded boy with chronic acne and trisomy 8 mosaicism suggest that the association of acne and chromosomal abnormality may not be limited to Y chromosome excess.

Acne Vulgaris↗
PubMed1982

Parental origin of chromosome abnormalities in spontaneous abortions.

Tissue cultures were initiated from 130 spontaneous abortion specimens and 81 were successfully karyotyped. Chromosome abnormalities were found in 50 cases: 12 with XO, 27 with trisomy, 6 with triploidy, 1 with tetraploidy and 4 others. The parental origin was determined in 11 cases of trisomy for an acrocentric chromosome. Two cases were uninformative while 9 non-disjunctions were determined and occurred during meiosis I: 7 were maternal and 2 paternal (both with trisomy 21). Three out of 7 cases with trisomy 16 were informative and resulted from a divisional error during the first meiotic division in the mother. All cases of triploidy were informative. They resulted from non-reduction during meiosis I in the mother (2) or dispermy (4).

Abortion, Spontaneous↗
PubMed1989

[The natural occurring incidence of chromosome abnormalities in 330 chorionic villi samples in the first trimester of pregnancy].

The natural occurring incidence of chromosome abnormalities (ICA) and its clinical significance were investigated in 330 chorionic villi samples (CVS) from the first trimester of pregnancy. It was found that the ICACVS was 5.67 per cent (11/194) in the normal group and 11.77 per cent (16/136) in the risk group. The difference between two groups was highly significant (P less than 0.01). The result shows that the pregnant women with threatened abortion, history of spontaneous abortion and greater than or equal to 40 years old are the high-risk factors. Special attention should be paid to these cases in clinical genetic counselling and prenatal diagnosis.

Abortion, Threatened↗
PubMed1990

Chromosome abnormalities in skin fibroblasts probably induced by an anti-cancer drug.

Chromosome findings in cultured skin fibroblasts from a patient treated with an anti-cancer drug, pepleomycin sulfate, for his penis cancer are reported. In two batches of specimens (days 16 and 34, respectively), out of 120 cells examined, a total of 26 abnormal cells (21.7%) were found with no common chromosome abnormalities; there were no clones. This cytogenetic pattern of abnormalities without clones in cultured skin fibroblasts differs from that seen in congenital disease or radiation-exposed skin fibroblasts. It is suggested that the anti-cancer agent is the most likely etiological factor for these uncloned chromosome abnormalities in cultured skin fibroblasts.

Bleomycin↗
PubMed1987

Chromosomal abnormalities in adult T-cell leukemia/lymphoma (ATL). A report of six cases with review of the literature.

Chromosomal studies were performed on six patients with adult T-cell leukemia (ATL). Structural abnormalities of chromosome 3 were the most common. In one case a complete loss of the short arm of chromosome 10 (10 p-) was noted while in another case a balanced translocation involving chromosome 10p and 4q was found. These abnormalities have not been previously reported. After reviewing the literature, it was concluded that chromosomes 3, 6, 10, 13, 14, and X were most frequently involved in abnormalities. Specific and consistent chromosomal abnormalities were noted in each study. Therefore, it is hypothesised that the mutation rate for this virus may be higher than first expected. Furthermore, the relative consistency of heterogeneous findings in different localities may reflect a geographic clustering of specific chromosomal abnormalities which may in turn be related to specific and geographically associated viral mutations. To support these suggestions not only are more cytogenetic data required but a molecular evaluation of these patients must be carried out to establish a relationship, if any, between genetic abnormalities and the epidemiology of ATL.

Adult↗
PubMed1990

[Chromosome abnormalities of the fertilized human egg].

In vitro fertilization enabled the study of lethal (parthenogenesis) or sublethal (triploidy, monosomy and trisomy) chromosomal abnormalities in man. According to the literature, 23 to 71% of preimplantation embryos carry a chromosomal defect. Various factors, such as delayed fertilization, early embryo fragmentation or elevated maternal age (greater than 35 years) are related to an increase in the incidence of chromosomal aberrations. These data reinforce the debate on a preimplantation genetic diagnosis in order to select for transfer only viable and apparently normal embryos.

Blastocyst↗
PubMed1981

Down's/Turner's mosaicism. Double aneuploidy as a rare cause of missed prenatal diagnosis of chromosomal abnormality.

Two babies with Down's/Turner's mosaic karyotype are reported. In each, because of advanced maternal age, chromosomal analysis had been carried out on the fluid obtained by amniocentesis in early pregnancy. Only the 46,X+ 21 cell line grew in the specimens and the extra 21 chromosome was wrongly identified as a Y chromosome, so that the fetus was thought to have a normal male karyotype, 46,XY. At birth both babies were phenotypically female with features predominantly of Down's syndrome and the correct karyotype was then identified. Twenty cases of this rare chromosomal abnormality are reviewed and one other living child who had been similarly wrongly diagnosed is reported.

Aneuploidy↗
PubMed1986

Unusual supernumerary chromosomes: types encountered in a referred population, and high incidence of associated maternal chromosome abnormalities.

In a 6-year period 128 patients with supernumerary autosomes were identified in our laboratory. The majority had "primary" trisomy, but 19 (15%) had extra, unusual chromosomes, not just a normal chromosome present in an extra copy. Of these, 18 were complex and did not resemble any one part of the standard chromosome complement. There was a preponderance of females among the 19 cases. Chromosome analysis of the parents in the 14 most recent cases revealed maternal chromosome abnormalities in 11 (79%). Of these 11, eight mothers had balanced reciprocal translocations; nondisjunction led to the smaller of their translocation chromosomes being passed on as the supernumerary chromosome in their offspring. Thus, nondisjunction of maternal translocations accounts for a major proportion of the unusual supernumerary chromosomes found by our laboratory. Advanced maternal age was noted in this group of mothers. Three mothers had supernumerary chromosomes themselves. We conclude that unusual supernumerary chromosomes (1) are not rare among patients referred for chromosome studies; (2) are generally not simple products of breakage; (3) are very frequently the result of malsegregation of a balanced maternal reciprocal translocation; and (4) are very difficult to characterize unless a balanced parental translocation is identified. Parental karyotypes should be obtained whenever a patient has an extra, unusual chromosome.

Adolescent↗
PubMed2006

X chromosomal abnormalities in basal-like human breast cancer.

Sporadic basal-like cancers (BLC) are a distinct class of human breast cancers that are phenotypically similar to BRCA1-associated cancers. Like BRCA1-deficient tumors, most BLC lack markers of a normal inactive X chromosome (Xi). Duplication of the active X chromosome and loss of Xi characterized almost half of BLC cases tested. Others contained biparental but nonheterochromatinized X chromosomes or gains of X chromosomal DNA. These abnormalities did not lead to a global increase in X chromosome transcription but were associated with overexpression of a small subset of X chromosomal genes. Other, equally aneuploid, but non-BLC rarely displayed these X chromosome abnormalities. These results suggest that X chromosome abnormalities contribute to the pathogenesis of BLC, both inherited and sporadic.

Alleles↗