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PubMed2001

Two supernumerary marker chromosomes, originating from chromosomes 6 and 11, in a child with developmental delay and craniofacial dysmorphism.

The interpretation of the significance of marker chromosomes, which can be encountered at prenatal diagnosis, is extremely problematic. Various factors contribute to the difficulty of clarifying the phenotypic risks of supernumerary marker chromosomes, including differences in the size, structure, and origin of marker chromosomes, as well as the occurrence of multiple marker chromosomes of different origin in the same proband. Research on marker chromosomes is currently in a data-accumulation phase. We report the presence of two marker chromosomes, originating from chromosomes 6 and 11, in a child with developmental delay and craniofacial dysmorphism and discuss the related literature.

Child, Preschool↗
PubMed2001

Comparative genomic sequencing reveals a strikingly similar architecture of a conserved syntenic region on human chromosome 11p15.3 (including gene ST5) and mouse chromosome 7.

Comparative genomics is a superior way to identify phylogenetically conserved features like genes or regions involved in gene regulation. The comparison of extended orthologous chromosomal regions should also reveal other characteristic traits essential for chromosome or gene function. In the present study we have sequenced and compared a region of conserved synteny from human chromosome 11p15.3 and mouse chromosome 7. In human, this region is known to contain several genes involved in the development of various disorders like Beckwith-Wiedemann overgrowth syndrome and other tumor diseases. Furthermore, in the neighboring chromosome region 11p15.5 extensive imprinting of genes has been reported which might extend to region 11p15.3. The analysis of approximately 730 kb in human and 620 kb in mouse led to the identification of eleven genes. All putative genes found in the mouse DNA were also present in the same order and orientation in the human chromosome. However, in the human DNA one putative gene of unknown function could be identified which is not present in the orthologous position of the mouse chromosome. The sequence similarity between human and mouse is higher in transcribed and exon regions than in non-transcribed segments. Dot plot analysis, however, reveals a surprisingly well-conserved sequence similarity over the entire analyzed region. In particular, the positions of CpG islands, short regions of very high GC content in the 5' region of putative genes, are similar in human and mouse. With respect to base composition, two distinct segments of significantly different GC content exist as well in human as in the mouse. With a GC content of 45% the one segment would correspond to "isochore H1" and the other segment (39% GC in human, 40% GC in mouse) to "isochore L1/L2". The gene density (one gene per 66 kb) is slightly higher than the average calculated for the complete human genome (one gene per 90 kb). The comparison of the number and distribution of repetitive elements shows that the proportion of human DNA made up by interspersed repeats (43.8%) is significantly higher than in the corresponding mouse DNA (30.1%). This partly explains why the human DNA is longer between the landmark genes used to define the orthologous positions in human and mouse.

Animals↗
PubMed2003

Supernumerary small marker chromosome (SMC) and uniparental disomy 22 in a child with confined placental mosaicism of trisomy 22: trisomy rescue due to marker chromosome formation.

Trisomy rescue is one of various proposed mechanisms in formation of supernumerary small marker chromosomes (SMC) and uniparental disomy (UPD). In the present report a small de novo marker chromosome derived from chromosome 14 or 22 was diagnosed at prenatal diagnosis due to maternal age. Follow up investigations at birth revealed mosaicism 47,XX,+mar/46,XX. Using FISH, the marker was positive for the probe D14/22Z1, but negative for the probes midi 54 and D22Z4. Using three informative markers both chromosomes 22 were shown to be inherited from the mother (UPDmat). The results are consistent with nondisjunction at maternal meiosis I. The girl is 18 months old now and phenotypically normal. Cardiac and abdominal malformations were excluded by sonographic examinations. Motor and mental development is according to or ahead of developmental milestones (free walking with 10 months, first words at 12 months). The case confirms that maternal UPD 22 most likely is not associated with clinical abnormalities. According to FISH results, UPD 22, and 47,XX,+22 in the placenta, we conclude that the SMC was derived from alpha satellite sequences of chromosome 22. This case for the first time gives evidence that early postzygotic reduction of a chromosome to a small marker chromosome is a real existing mechanism to rescue a conceptus with trisomy.

Chromosomes, Human, Pair 14↗
PubMed2005

An analphoid marker chromosome inv dup(15)(q26.1qter), detected during prenatal diagnosis and characterized via chromosome microdissection.

A small, mosaic, C-band negative marker chromosome was detected in amniocyte cultures during prenatal diagnosis due to advanced maternal age. Following spontaneous premature labor at 29 weeks gestation, a dysmorphic infant was delivered, with flat nasal bridge, short palpebral fissures, micrognathia, high forehead, low-set ears, telecanthus and corneal dystrophy. Additional folds of skin were present behind the neck, and feet, fingers and toes were abnormally long. The child died at age five days, after two days of renal failure. The origin of the marker chromosome was subsequently identified from a cord blood sample, via chromosome microdissection. Through reverse FISH, we found the marker to be an inverted duplication of the region 15q26.1-->qter. FISH with alphoid satellite probe was negative, while whole chromosome 15 paint was positive. Both ends of the marker chromosome were positive for the telomeric TTAGGG probe. These data, plus the G-banding pattern, identified the marker as an analphoid, inverted duplicated chromosome, lacking any conventional centromere. We discuss the etiology and clinical effects of this marker chromosome, comparing it to the few reported cases of "tetrasomy 15q" syndrome. We also discuss the possible mechanisms that are likely responsible for this neocentromere formation.

Abnormalities, Multiple↗
PubMed2006

Analysis of mouse conceptuses with uniparental duplication/deficiency for distal chromosome 12: comparison with chromosome 12 uniparental disomy and implications for genomic imprinting.

Distal mouse chromosome 12 is imprinted. Phenotypic analysis of mouse embryos with maternal or paternal uniparental disomy for the whole of chromosome 12 has characterized the developmental defects associated with the altered dosage of imprinted genes on this chromosome. Here we conduct a characterization of maternal and paternal Dp(dist12) mice using the reciprocal translocation T(4;12)47H. This limits the region analysed to the chromosomal domain distal to the T47H breakpoint in B3 on mouse chromosome 12. Both MatDp(dist12)T47H and PatDp(dist12)T47H conceptuses are non-viable and the frequency of recovery of Dp(dist12) conceptuses by 10.5 days post coitum (dpc) was lower than expected after normal adjacent-1 disjunction. A subset of MatDp(dist12) embryos can survive up to one day post partum. In contrast to paternal uniparental disomy 12 embryos, no live PatDp (dist12) embryos were recovered after 16.5 days of gestation. Other phenotypes observed in maternal and paternal chromosome 12 uniparental disomy mice are recapitulated in the Dp(dist12) mice and include placental, muscle and skeletal defects. Additional defects were also noted in the skin of both MatDp(dist12) and maternal uniparental disomy 12 embryos. This study shows that the developmental abnormalities associated with the altered parent of origin for mouse chromosome 12 can be attributed to the genomic region distal to the T47H breakpoint.

Animals↗
PubMed1983

Sperm chromosome analysis of a man heterozygous for a pericentric inversion of chromosome 3.

Using a procedure in which human sperm were allowed to fertilize zona-free golden hamster (Mesocricetus auratus) eggs in vitro, the sperm chromosomes of a man heterozygous for inv(3) (p11q11) were analyzed. When the chromosomes were Q-banded, the inverted chromosome had the bright centromeric band on the short arm rather than on the long arm, as was seen in the normal No. 3. One hundred and eleven sperm chromosome spreads were examined, of which 64 contained the normal chromosome and 47 the inverted one. This was not significantly different from the expected 1:1 ratio. No sperm containing a chromosome imbalance caused by a crossover within the inversion were seen. Ten (8.1%) of the sperm contained chromosome abnormalities unrelated to the inversion. The ratio of X- to Y-bearing sperm was 55:45.

Animals↗
PubMed2005

The element(s) at the nontranscribed Xist locus of the active X chromosome controls chromosomal replication timing in the mouse.

In female mammalian cells, the inactive X chromosome is replicated late in S phase while the active X chromosome is replicated earlier. The replication times of the X chromosomes reflect a general trend in which late replication is associated with gene repression and earlier replication with transcriptional competence. The X-linked Xist gene is expressed exclusively from the inactive X chromosome where it is involved in the initiation and maintenance of X-inactivation. In contrast, no biological activity has been assigned to the Xist locus of the active X chromosome where the Xist gene is transcriptionally silenced. Here, we provide evidence that the element(s) at the nontranscribed Xist locus of the active X chromosome controls chromosomal replication timing in cis.

Animals↗
PubMed2001

Characterization of allelic and nucleotide variation between the RAGE gene on chromosome 6 and a homologous pseudogene sequence to its 5' regulatory region on chromosome 3: implications for polymorphic studies in diabetes.

Activation of the receptor for advanced glycation end products (RAGE) appears to be a key mechanism in the pathogenesis of diabetic vascular disease, making RAGE a candidate gene for investigation. RAGE is located in the major histocompatibility complex locus on chromosome 6, which contains a multitude of overlapping and duplicated genes involved predominantly in inflammatory and immune responses. The RAGE 5' flanking region from -505 in a 5' direction overlaps with PBX2, a gene that has a pseudogene copy on chromosome 3, making any studies of polymorphisms in this duplicated region potentially fraught with error. In this study we have addressed these issues by confirming RAGE as a predominantly single-copy gene and PBX2 to have two gene copies in the haploid human genome. We have characterized the gene:pseudogene differences between RAGE/PBX2 on chromosome 6 and PsiPBX2 on chromosome 3, which include a change from C to A at position -1139 RAGE/+2298 PBX2, previously reported as a polymorphism. Single chromosome-specific DNA amplification of the duplicated region has clarified five polymorphisms to be on chromosome 3 and one (at -1202 RAGE/+2234 PBX2) to be on chromosome 6. In conclusion, this study provides essential data for the study of RAGE and its genetics.

3' Untranslated Regions↗
PubMed1999

Ectopic NORs on human chromosomes 4qter and 8q11: rare chromosomal variants detected in two families.

Two different NOR bearing non-acrocentric chromosomes were detected during prenatal diagnosis performed on two probands because of advanced maternal age. In the first case, a chromosome 4 carried a NOR in the telomeric region of the long arm (4qs), while in the second case a NOR was inserted into chromosome 8q11. Family analysis showed the variant chromosomes to be transmitted through at least three generations in each family. There were no reports of reproductive problems or phenotypic effects in the carriers of these chromosomes, indicating the benign character of the aberrant chromosomes. In order to characterise the chromosomal variants more precisely, various differential banding techniques were applied.

Chromosomes, Human, Pair 4↗
PubMed2000

[The application of fluorescence in situ hybridization performed on the decolorized G-banding chromosomes in detecting the marker chromosomes of gastric cancer].

OBJECTIVE: Using a rapid, accurate method that detects the marker chromosomes of gastric cancer and enhancing the ability of discriminating complicated chromosome rearrangements of gastric cancer. METHODS: The improved method of fluorescence in situ hybridization(FISH) performed on the decolorized G-banding chromosome was used. RESULTS: The changes of two marker chromosomes (M1, M2) of the cell line(SGC-7901) of gastric cancer and one marker chromosomes(M3) of one primary gastric cancer were respectively analyzed by this method. The M1, M2 and M3 had complicated structural chromosome aberrations: del(7)(p15)/del(7)(q22), t(1;3)(p11;q11) and del(7)(q32). CONCLUSION: This method showed strong signals, low backgrounds and well-repetitions. It may play an important part in exploring the chromosome rearrangements in the process of pathogenesis and development of gastric cancer.

Chromosome Aberrations↗
PubMed2001

[Application of chromosome painting technique to analysis of structural aberration of human chromosomes].

OBJECTIVE: This study was aimed at using chromosome painting technique to detect translocation, especially microtranslocations, on chromosomes in comparison with G-banding analysis. METHODS: Chromosome painting technique was applied to analysis of metaphase chromosomes of patients for detecting translocations with biotin-labeled chromosomes X, Y, 14q, 10 specific probes. RESULTS: Fluorescence in situ hybridization FISH signals were shown clearly in slides even in specimen stored at room temperature for 10 years and at -80 centigrade degree. Translocations were located precisely. CONCLUSION: Microtranslocations, which are hard to analyze by G-banding, can be detected exactly using chromosome painting technique with G-band karyotype on metaphase chromosome.

Adult↗
PubMed1985

The pronatriodilatin gene is located on the distal short arm of human chromosome 1 and on mouse chromosome 4.

Atrial natriuretic factors (ANF) are polypeptides having natriuretic, diuretic, and smooth muscle-relaxing activities that are synthesized from a single larger precursor: pronatriodilatin. Chromosomal assignment of the gene coding for human pronatriodilatin was accomplished by in situ hybridization of a [3H]-labeled pronatriodilatin probe to human chromosome preparations and by Southern blot analysis of somatic cell hybrid DNAs with normal and rearranged chromosomes 1. The human pronatriodilatin gene was mapped to the distal short arm of chromosome 1, in band 1p36. Southern blot analysis of mouse X Chinese hamster somatic cell hybrids was used to assign the mouse pronatriodilatin gene to chromosome 4. This assignment adds another locus to the conserved syntenic group of homologous genes located on the distal half of the short arm of human chromosome 1 and on mouse chromosome 4.

Animals↗
PubMed1981

Automatic chromosome analysis. II. Karyotyping of banded human chromosomes using band transition sequences.

Human chromosomes, represented by band transition sequences, chromosome area, centromeric index by area and centromeric index by density, were karyotyped by computer. A reference set of chromosomes provided frequencies of occurrence of each density class and difference class of the band transition sequence as well as of each of the three global features. The karyotyping program was designed to handle all metaphases, even those from which severely bent and overlapped chromosomes were excluded. In one experiment, 21 metaphases were karyotyped on the basis of a reference set and the results were compared with earlier results of visual analysis of band transition profiles developed from band transition sequences: 0.8% errors were made in the visual experiment and 1.4% errors were made in the computer based experiment. In a second experiment, 179 metaphases were divided into reference and test sets and karyotyped by computer with an error rate of 3.4%. By further analysis it was found that metaphases with many misclassified chromosomes could often be automatically distinguished from metaphases with few errors. Thus by automatic rejection of 7% of the metaphases the error rate could be reduced to 2.6%. The computer program for chromosome karyotyping will now be implemented in a semi-automatic system for practical clinical chromosome analysis.

Chromosome Banding↗
PubMed1995

Suppression of tumorigenicity in three different cell lines of human oral squamous cell carcinoma by introduction of chromosome 3p via microcell-mediated chromosome transfer.

It has been suggested that loss of the short arm of chromosome 3 is one of the most frequent abnormalities in human head and neck cancers including oral squamous cell carcinomas (SCC) and that one or more putative tumor suppressor gene(s) which may contribute to the initiation and/or progression of these tumors might be located on chromosome 3p. In this study, we examined the effects of introducing human chromosome 3 or 7 by microcell hybridization on the tumor-associated phenotypes of three different human oral SCC cell lines, HSC-2, HSC-3 and HSC-4. Transfer of a single chromosome 3p completely suppressed the tumorigenicity of all three parental cell lines, which showed a significant decrease in growth rate in vitro and morphological changes. In contrast, transfer of chromosome 7 had no effect on HSC-2 and HSC-4 cells, although it suppressed the tumorigenicity of HSC-3 cells without modifying their in vitro growth properties. Our findings provide additional confirmatory evidence that loss or inactivation of putative tumor suppressor gene(s) present on chromosome 3p might be primarily involved in the development of human oral SCC. The possibility that chromosome 7 may carry another tumor suppressor gene(s) is also discussed.

Animals↗
PubMed1995

Molecular studies of chromosomal mosaicism: relative frequency of chromosome gain or loss and possible role of cell selection.

Studies of uniparental disomy and origin of nonmosaic trisomies indicate that both gain and loss of a chromosome can occur after fertilization. It is therefore of interest to determine both the relative frequency with which gain or loss can contribute to chromosomal mosaicism and whether these frequencies are influenced by selective factors. Thirty-two mosaic cases were examined with molecular markers, to try to determine which was the primary and which was the secondary cell line: 16 cases of disomy/trisomy mosaicism (5 trisomy 8, 2 trisomy 13, 1 trisomy 18, 4 trisomy 21, and 4 involving the X chromosome), 14 cases of 45,X/46,XX, and 2 cases of 45,X/47,XXX. Of the 14 cases of mosaic 45,X/46,XX, chromosome loss from a normal disomic fertilization predominated, supporting the hypothesis that 45,X might be compatible with survival only when the 45,X cell line arises relatively late in development. Most cases of disomy/trisomy mosaicism involving chromosomes 13, 18, 21, and X were also frequently associated with somatic loss of one (or more) chromosome, in these cases from a trisomic fertilization. By contrast, four of the five trisomy 8 cases were consistent with a somatic gain of a chromosome 8 during development from a normal zygote. It is possible that survival of trisomy 8 is also much more likely when the aneuploid cell line arises relatively late in development.

Aneuploidy↗
PubMed1996

Proliferation kinetics of chorionic villi in chromosomally normal and abnormal spontaneous abortions analyzed by premature chromosome condensation and northern blot.

The activity of cell proliferation in human chorionic villi (CV) obtained from early spontaneous abortions (SAB) and from elective abortions (EAB) was determined by means of premature chromosome condensation (PCC), and by Northern blot analysis of expression of proliferation antigens Ki67 and PCNA. The rate of chromosome aberrations among the SABs was 57%, while the EABs, taken as controls, were shown to be chromosomally normal. PCCs were induced by fusion of the chorionic interphase cells with mitotic Chinese hamster ovary (CHO) cells. To analyze the proliferation stages of the chorionic G1-interphases, the potential proliferation index (PPI) was ascertained. The PPI values found in SABs ranged from 36% to 97% as described for intensely proliferating tissues. They did not differ from the values found in the controls (34-90%), indicating maintenance of proliferation activity of CV cells even after death of the embryo in missed abortions. No significant PPI differences were observed between the abortion groups with different cytogenetic results. The expression of proliferation associated antigens Ki67 and PCNA showed no significant differences between mean values of the total of SABs and of the controls. However, the comparison of mean values of chromosomally abnormal with chromosomally normal SABs revealed a significantly reduced Ki67 activity in the SABs with chromosome aberrations. A similar results was obtained when comparing mean values of Ki67 and PCNA expression from trisomic SABs with those of the controls. By further subdivision of chromosome aberrations a decrease for the expression of both antigens in chorionic villi from early lethal trisomies, and a significantly increased Ki67- and PCNA-expression in triploidies became evident.

Abortion, Induced↗
PubMed1997

Advanced-stage cervical carcinomas are defined by a recurrent pattern of chromosomal aberrations revealing high genetic instability and a consistent gain of chromosome arm 3q.

We have analyzed 30 cases of advanced-stage cervical squamous cell carcinoma (stages IIb-IV) by comparative genomic hybridization (CGH). The most consistent chromosomal gain in the aneuploid tumors was mapped to chromosome arm 3q in 77% of the cases. Acquisition of genetic material also occurred frequently on Iq (47%), 5p (30%), 6p (27%), and 20 (23%). Recurrent losses were mapped on 2q (33%), 3p (50%), 4 (33%), 8p (23%), and 13q (27%). High-level copy number increases were mapped to chromosome 8, chromosome arms 3q, 5p, 8q, 12p, 14q, 17q, 19q, 20p, and 20q, and chromosomal bands 3q26-27, 9p23-24, 11q22-23, and 12p13. In the majority of the cases, the presence of high-risk human papilloma virus genomes was detected. High proliferative activity was accompanied by crude aneuploidy. Increased p21/WAF-I activity, but low or undetectable expression of TP53 were representative for the immunophenotype. This study confirms the importance of a gain of chromosome arm 3q in cervical carcinogenesis and identifies additional, recurrent chromosomal aberrations that are required for progression from stage I tumors to advanced-stage carcinomas.

Adult↗
PubMed1998

FISH and molecular study of autosomal supernumerary marker chromosomes excluding those derived from chromosomes 15 and 22: I. Results of 26 new cases.

The chromosomal origins and in some cases the molecular composition of 26 autosomal supernumerary marker chromosomes (SMC) were identified using combined fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) techniques. Fifteen were de novo, 4 maternally and 2 paternally transmitted and in 5 cases the parental origin is not known. Eleven cases were non-mosaic and fifteen cases had SMC cell lines ranging from 8-87%. Ten cases were ascertained prenatally, nine postnatally with abnormal phenotypes, three with poor reproductive histories and four co-incidentally. Five SMC were small rings from chromosomes 3, 6 (2 cases), 20 and 21; 8 were bisatellited from chromosomes 13/21 (4 cases), 14 (3 cases) and 14/22 (1 case). The remaining 13 appeared to be minutes comprising centromeric material only from chromosomes 1, 4, 12, 13/21 (2 cases), 14 (3 cases), 16 (2 cases), 19; 5/19, and a centric fusion involving 13 or 21 and 14. Euchromatin was detected in 9 out of 18 SMC tested with paints and/or PCR, and abnormal phenotypes were most commonly observed in patients with small ring shaped SMCs containing euchromatic sequences. Uniparental paternal isodisomy (UPD) for chromosome 6 was detected in one patient but was the only example of UPD for the normal homologues in association with an autosomal SMC in an overall total of 30 cases examined.

Chromosome Aberrations↗