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PubMed1983

Fragile X chromosome and chromosome condensation.

The effect of chromosome condensation on the frequency of expression of the fragile X chromosome was examined. Chromosome decondensation substances were tested for their ability to elicit expression or improve frequencies of expression of the fragile X chromosome in five patients. The substances tested included the AT specific DNA ligands ethidium bromide, Hoechst 33258, and netropsin, and the GC specific substances actinomycin D and olivomycin. Under culture conditions appropriate for eliciting fragile X expression none of the decondensation compounds studied significantly altered frequencies of expression, nor did any of the substances elicit fragile X expression under conditions that normally suppress fragile X expression. The fragile X was found to be more frequently evident in less condensed chromosome preparations from fibroblasts. The implications of these findings with respect to the nature of fragile sites are discussed.

Aged↗
PubMed1993

Use of FISH to detect chromosomal translocations and deletions. Analysis of chromosome rearrangement in synovial sarcoma cells from paraffin-embedded specimens.

Retrospective cytogenetic analysis was performed on paraffin-embedded cells from five cases of synovial sarcoma to evaluate the frequency of the X;18 translocation characteristic of this tumor. Fluorescent in situ hybridization with DNA probes for the centromeres of chromosomes X and 18 was used with whole chromosome painting probes for X and 18. Translocation was inferred when there were only two X and 18 centromere signals but three painting probe signals of unequal size. On this basis it was possible to identify the t(X;18) in three cases. The fourth case was found to have extra copies of chromosome 18 without translocation, while the fifth case, the only one with a questionable diagnosis, had a normal chromosome pattern with a minor clone showing a translocated 18 but a normal X. Thus this study demonstrates the feasibility and value of using fluorescent in situ hybridization to detect chromosome rearrangements in archival tumor specimens.

Adolescent↗
PubMed1996

Induction and repair of chromosome aberrations in scid cells measured by premature chromosome condensation.

Severe combined immunodeficient (scid) murine cells, which are defective in both repair of DNA double-strand breaks and V(D)J recombination, are deficient in DNA-dependent protein kinase (DNA-PK), a protein which forms an activated complex with the DNA end-binding Ku proteins (p80 and p70) upon association with damaged DNA. Xrs 5 cells are deficient in the Ku p80 protein and also fail to form an active DNA-PK repair complex. Since both scid and xrs cells are defective in the same protein complex, we compared the kinetics of chromosome repair in scid cells to results published previously for xrs 5 cells. C.B-17 cells, scid cells and scid cells complemented with a single human chromosome 8 were irradiated with 6 Gy and allowed to repair from 0-24 h before fusion to HeLa cells for chromosome condensation. Breaks and dicentrics were visualized by fluorescence in situ hybridization. All cells had the same initial amount of chromosome damage, but scid cells had a slower rate of rejoining, more unrejoined breaks and more dicentrics than C.B-17 and scid cells with human chromosome 8. The scid cells appear to respond differently than xrs 5 cells, despite both cells lacking an essential component of the same DNA repair complex.

Algorithms↗
PubMedDate not supplied

[An analysis of human marker chromosomes originating from chromosome 21 by using in situ hybridization].

Four cases of patients with additional marker chromosomes are described. The clinical, cytogenetic and molecular cytogenetic methods have been used for investigation. The identification of marker chromosomes was made by using in situ hybridization and the collection of chromosome-specific DNA probes. All marker chromosomes were determined as originated from chromosome 21 with break-points in the region between 21q11 and 21q22.

Chromosome Aberrations↗
PubMed1997

Characterization of four yeast artificial chromosome clones mapped to human chromosome 21q22.1 with eight markers.

Yeast artificial chromosome (YAC) clones have been successfully utilized to generate a YAC contig map of the long arm of human chromosome 21 (Hu21q). The chromosome subband of 21q22.1 where five genetic loci (IFNAR1, IFNAR2, CRFB4, AF-1, and GART) are mapped is a gene-rich region and needs to be characterized in further detail. YAC D142H8 and YAC F136C5, which were characterized previously by a functional YAC expression procedure, and two new YAC clones, YAC 872B5 and YAC 876D4 located at 21q22.1 whose YAC sizes are 800 kb and 1,500 kb, respectively, were used in this study. To obtain more markers useful for making a detailed physical map of the region, a purified yeast artificial chromosome (YAC D142H8) was used to screen the 3 x 1 S cDNA library. As a result three anonymous cDNA clones (Kmy1, Kmy2, and Qorf4) were obtained, and the nucleotide sequences of Kmy1 and Kmy2 were determined. In an attempt to make a detailed physical map of the region, the locations of five known genes as well as the three new markers were determined on the four YACs by Southern blot analysis. YAC 872B5 contained all markers except GART while YAC F136C5, YAC D142H8, and YAC 876D4 contained three markers (CRFB4, IFNAR1, and IFNAR2), four markers (Kmy1, Kmy2, Qorf4 and AF-1), and four markers (Kmy1, Kmy2, Qorf4 and GART), respectively. YAC 872B5 may represent 1,500 kb of the 21q22.1 subband and half of the 3 x 1 S region, so it should be very useful for studying the relevent region of the human chromosome functionally and physically.

Base Sequence↗
PubMed1998

FISH and molecular studies of autosomal supernumerary marker chromosomes excluding those derived from chromosome 15: II. Review of the literature.

Using fluorescence in situ hybridization (FISH), supernumerary marker chromosomes (SMC) from all the human autosomes except chromosome 5, have now been described, most being derived from the acrocentric autosomes. This review summarizes the results of 168 cases of autosomal SMC excluding those from chromosome 15 where FISH has been used to define the chromosomal origin of the SMC and from which phenotypic information is available. Although the number of reported cases from some of the chromosomal SMC groups remains small, the pooled data suggest that the risk of an abnormal phenotype associated with a randomly ascertained de novo SMC derived from the acrocentric autosomes (excluding 15s) is approximately 7% compared with approximately 28% for SMCs derived from the nonacrocentric autosomes.

Chromosome Aberrations↗
PubMed1998

De novo apparently balanced complex chromosome rearrangement (CCR) involving chromosomes 4, 18, and 21 in a girl with mental retardation: report and review.

We describe a complex and unique, de novo apparently balanced translocation involving chromosomes 4, 18, and 21 with 4 breakpoints, in a patient who was referred for an evaluation of possible fragile-X syndrome. Fluorescence in situ hybridization (FISH) confirmed the complexity of the rearrangement and showed the derivative 21 to be composed of 3 distinct segments derived from chromosomes 21, 18, and 4. The derivative chromosome 18 had undergone a double translocation, the first such event to be described in constitutional complex chromosomal rearrangements (CCRs) involving chromosome 18. A review of these CCRs suggests the existence of a breakpoint "hot spot" on 18q21.

Child, Preschool↗
PubMed1995

Cyclophilin A, the major intracellular receptor for the immunosuppressant cyclosporin A, maps to chromosome 7p11.2-p13: four pseudogenes map to chromosomes 3, 10, 14, and 18.

Cyclophilin A (CyP-A), the major intracellular receptor for the immunosuppressant cyclosporin A (CsA), is a member of the immunophilin class of proteins, which all possess peptidyl-prolyl cis-trans isomerase activity and, therefore, are believed to be involved in protein folding and/or intracellular protein transport. The CyP-A protein is encoded by a single gene; in addition, 15 pseudogenes have been identified. Recently, specific binding of CyP-A to the human immunodeficiency virus type 1 (HIV-1) gag protein has been reported. Interestingly, this interaction can be inhibited by the immunosuppressant CsA and also by nonimmunosuppressive, CyP-A-binding CsA derivatives, which were also shown to exhibit potent anti-HIV-1 activity. Results thus indicate that CyP-A may have an essential function in HIV-1 replication. Using a panel of somatic rodent-human cell hybrids and PCR technology, we localized the coding cyclophilin A gene (PPIA) on chromosome 7 and four pseudogenes (PPIP2, PPIP3, PPIP4, and PPIP6) on chromosomes 14, 10, 18, and 3, respectively. Using chromosome 7 and chromosome 10 deletion hybrid panels, we were able to localize further the coding gene to the region 7p11.2-p13, as confirmed by fluorescence in situ hybridization analysis, and one pseudogene (PPIP3) to the region 10q11.2-q23. This is the first report on the regional mapping of members of the CyP-A gene family.

Amino Acid Isomerases↗
PubMed1982

Human chromosomal polymorphism. III. Chromosomal Q polymorphism in Mongoloids of northern Asia.

Q-heterochromatin variants in seven autosomes (3, 4, 13-15, 21, 22) were studied in two Mongoloid populations of northern Asia (Chukchi and Khakass). Q-staining was obtained using propylquinacrine mustard. Of 132 Chukchi individuals aged 13 to 20 years, 124 had Q-polymorphic chromosomes, while eight (6.0%) had no bands with fluorescence levels 4 and 5. The mean number of Q variants was 2.2 per individual. Of the 120 Khakass individuals aged 14 to 17 years, 112 had Q-polymorphic chromosomes, while eight (6.7%) had no Q variants with fluorescence levels 4 and 5. The mean number of Q variants was 2.5 per individual. No differences were found in the frequency of Q variants between sexes in the two populations. There was complete agreement between the observed homo- and heteromorphic frequencies and those predicted by the law of Hardy-Weinberg. As the Mongoloid populations of northern Asia showed statistically significant homogeneity both in the frequency of Q variants and the distribution of homo- and heteromorphic variants, they were examined as a single group--that of northern Mongoloids. The following questions are discussed: (1) the possible selective value of chromosomal Q-heterochromatin material in the adaptation of human populations to certain extreme environmental factors, in particular to cold and hypoxia; (2) the intraracial heterogeneity of Asian Mongoloids; (3) the taxonomic value of chromosomal Q polymorphism in ethnic anthropology.

Adolescent↗
PubMed2006

Unbalanced inherited complex chromosome rearrangement involving chromosome 8, 10, 11 and 16 in a patient with congenital malformations and delayed development.

Complex chromosome rearrangements (CCR) are rare structural chromosome aberrations that can be found in patients with phenotypic abnormalities or in phenotypically normal patients presenting, however, recurrent miscarriages or infertility. Conventional karyotype generally allows their identification. However, molecular cytogenetic methods can reveal subtle rearrangements. We report, here, the identification of an unbalanced maternally inherited CCR in a boy with multiple congenital malformations and delayed development. High-resolution karyotype completed by molecular cytogenetic prompted us to precise the rearrangements. The healthy mother was found to carry a balanced de novo CCR that implicates four chromosomes (8, 10, 11 and 16), six breakpoints, three translocations and an insertion. The malsegregation of this CCR had led, in her son, to partial 10p12.3 to 10p14 deletion, a chromosomal region associated with the DiGeorge like phenotype.

Abnormalities, Multiple↗
PubMed2006

An exceptional complex chromosomal rearrangement (CCR) with eight breakpoints involving four chromosomes (1;3;9;14) in an azoospermic male with normal phenotype.

A 27-year-old man was referred for chromosome analysis due to infertility caused by azoospermia. Chromosome analysis by conventional karyotyping, multicolour FISH (M-FISH) and multicolour banding (MCB) analysis revealed an apparently balanced translocation between chromosomes 1, 3, 9 and 14 as well as an additional inverted insertion of 3q material with a total of eight breakpoints. Due to the diversity of theoretically unbalanced products of meiotic recombination in this exceptional complex chromosomal rearrangement a successful result of assisted reproduction seems unlikely.

Adult↗
PubMed1998

From amplification to gene in thyroid cancer: a high-resolution mapped bacterial-artificial-chromosome resource for cancer chromosome aberrations guides gene discovery after comparative genome hybridization.

Chromosome rearrangements associated with neoplasms provide a rich resource for definition of the pathways of tumorigenesis. The power of comparative genome hybridization (CGH) to identify novel genes depends on the existence of suitable markers, which are lacking throughout most of the genome. We now report a general approach that translates CGH data into higher-resolution genomic-clone data that are then used to define the genes located in aneuploid regions. We used CGH to study 33 thyroid-tumor DNAs and two tumor-cell-line DNAs. The results revealed amplifications of chromosome band 2p21, with less-intense amplification on 2p13, 19q13.1, and 1p36 and with least-intense amplification on 1p34, 1q42, 5q31, 5q33-34, 9q32-34, and 14q32. To define the 2p21 region amplified, a dense array of 373 FISH-mapped chromosome 2 bacterial artificial chromosomes (BACs) was constructed, and 87 of these were hybridized to a tumor-cell line. Four BACs carried genomic DNA that was amplified in these cells. The maximum amplified region was narrowed to 3-6 Mb by multicolor FISH with the flanking BACs, and the minimum amplicon size was defined by a contig of 420 kb. Sequence analysis of the amplified BAC 1D9 revealed a fragment of the gene, encoding protein kinase C epsilon (PKCepsilon), that was then shown to be amplified and rearranged in tumor cells. In summary, CGH combined with a dense mapped resource of BACs and large-scale sequencing has led directly to the definition of PKCepsilon as a previously unmapped candidate gene involved in thyroid tumorigenesis.

Adenocarcinoma, Follicular↗
PubMed1964

DNA CONTENTS OF CHROMOSOME PH1 AND CHROMOSOME 21 IN HUMAN CHRONIC GRANULOCYTIC LEUKEMIA.

The Philadelphia chromosome, characteristic of chronic granulocytic leukemia, contained 61+/-1 percent as much DNA as a number 21 (or 22) chromosome from which it is believed to be derived. The remaining 39 percent represents 0.5 percent of a diploid chromosome complement, approximately 2 x 10(7) nucleotide pairs; the method used was not sensitive enough to detect whether it had been translocated to other chromosomes.

Cell Nucleus↗
PubMed1998

Cytogenetic and morphologic characteristics of gastrointestinal stromal tumors. Recurrent rearrangement of chromosome 1 and losses of chromosomes 14 and 22 as common anomalies.

We present cytogenetic findings in five gastrointestinal stromal tumors (GISTs). Three of these five cases had abnormal karyotypes with clonal chromosomal aberrations. The most common karyotypic pattern was a combined loss of chromosomes 14 and 22 in a total of three cases. Among these cases, additional recurrent chromosomal abnormalities were loss of 1p and/or 9, detected in two cases each. Another karyotypic feature consisted of polyploidisation, leading to hypotetraploid chromosome numbers in one case. These cytogenetic results provide evidence for a characteristic karyotypic pattern consisting of -14 and -22 in a subset of GISTs.

Chromosome Aberrations↗
PubMed1990

Reassessment of two apparent deletions of chromosome 16p to an ins(11;16) and a t(1;16) by chromosome painting.

Two apparent deletions of the short arm of chromosome 16 were studied by in situ hybridisation using biotinylated DNA from a chromosome 16 specific cosmid library (chromosome painting). One abnormality was delineated as a t(1;16)(p36;p12) and the other as a ins(11;16)(q13;p13.13p13.3). Apparently unbalanced de novo abnormalities detected by classical cytogenetic procedures should be interpreted with caution. In situ hybridization using DNA from chromosome specific libraries provides the appropriate technology to delineate such abnormalities.

Adult↗
PubMedDate not supplied

[Multiple chromosome aberrations in 3 generations of a family and Down's syndrome resulting from partial trisomy of chromosome 21 (q21--q22)].

Two balanced translocations (1; 16) (q22; q11) and t(21; 22) (q21; p11), partial inversion of chromosome 9 and variant 16gh + were detected in the family of the child with Down's syndrome. The proband clinical picture was due to trisomy of the distal region of the long arm of chromosome 21 (q21----q22). Proband's karyotype was 46, XY, --22, +der(22), t(21; 22)mat, inv(9). Carriers of variant 16gh+ had a normal phenotype and a normal reproductive function. The relation is discussed of the balanced translocations and C-heterochromatin to the development of following chromosomal aberrations. A probability prediction of the progeny is given. It is advisable to make a prenatal diagnosis of the fetal chromosome set for each subsequent pregnancy.

Adult↗
PubMed1998

FISH analysis of a complex chromosome rearrangement involving nine breakpoints on chromosomes 6, 12, 14 and 16.

We report the prenatal diagnosis of an apparently balanced de novo complex chromosome rearrangement (CCR) which involved nine breakpoints on four different chromosomes. Fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY) were performed as an adjunct to G-banding for characterization of the abnormal chromosomes. The 22-week female fetus showed minor dysmorphic features including dolichocephaly, broad fingernails, tibial bowing, clubfoot, thoracolumbar scoliosis and hypoplastic toenails. Autopsy revealed gall-bladder hypoplasia and an atrial septal defect. Chromosome analysis of fetal tissue confirmed the presence of the complex rearrangement.

Abnormalities, Multiple↗