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Wayseen Wang - One of the best experts on this subject based on the ideXlab platform.

  • prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary Marker Chromosome derived from Chromosome 21q11 2 q21 1 and a literature review
    Taiwanese Journal of Obstetrics & Gynecology, 2017
    Co-Authors: Chihping Chen, Yenni Chen, Li Feng Chen, Schu-rern Chern, Ming Chen, Shin-wen Chen, Shun-ping Chang, Chenju Lin, Wayseen Wang
    Abstract:

    Objective We present prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary Marker Chromosome (sSMC) derived from Chromosome 21q11.2-q21.1, and we review the literature of an sSMC(21) with a duplication of 21q11.2-q21.1.

  • detection of paternal uniparental disomy 9 in a neonate with prenatally detected mosaicism for a small supernumerary Marker Chromosome 9 and a supernumerary ring Chromosome 9
    Taiwanese Journal of Obstetrics & Gynecology, 2017
    Co-Authors: Chihping Chen, Schu-rern Chern, Ming Chen, Shin-wen Chen, Shih-ting Lai, Shun-ping Chang, Chen-wen Pan, Liangkai Wang, Chienwen Yang, Wayseen Wang
    Abstract:

    Abstract Objective We present the association of paternal uniparental disomy (UPD) 9 with mosaicism for a small supernumerary Marker Chromosome 9 [sSMC(9)] and a supernumerary ring Chromosome 9 [r(9)]. Materials and methods A 38-year-old woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar [25]/48,XY,+mar,+r(9) [4]/47,XY,+r(9) [1]/46,XY [6]. The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) of cultured amniocytes revealed a result of de novo 9p13.1q21.11 (38,792,472–71,026,063) × 2.64. The Marker Chromosome was determined to be an sSMC(9) by spectral karyotyping and aCGH. A phenotypically normal baby was delivered at 38 weeks of gestation. During pediatric follow-ups at age two years, the neonate manifested normal psychomotor and growth development. Cytogenetic analysis, metaphase fluorescence in situ hybridization (FISH), single nucleotide polymorphism (SNP) aCGH and polymorphic DNA Marker analysis were performed on the peripheral blood of the neonate. Results The neonate's blood had the following results. Metaphase FISH confirmed coexistence of the sSMC(9) and the supernumerary r(9). The karyotype was 47,XY,+sSMC(9) [14]/48,XY, +sSMC(9),+r(9) [10]/47,XY,+r(9) [6]/46,XY [10]. SNP aCGH revealed arr 9p22.3q21.11 (14,234,165–71,035,608) × 2–3, arr 9p24.3p22.3 (216,123–14,629,321)hmz, arr 9p21.3p13.2 (24,769,722–36,732,597)hmz and arr 9q21.11q34.3 (71,013,799–141,011,581)hmz. Polymorphic DNA Marker analysis showed paternal isodisomy 9. Conclusion Individuals with mosaicism for sSMC(9) and supernumerary r(9) may be associated with paternal UPD 9.

  • Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary Marker Chromosome derived from Chromosome 11
    Elsevier, 2017
    Co-Authors: Chihping Chen, Schu-rern Chern, Ming Chen, Pu-tsui Wang, Shin-wen Chen, Shih-ting Lai, Shun-ping Chang, Chen-wen Pan, Wayseen Wang
    Abstract:

    Objective: We present prenatal diagnosis and molecular cytogenetic characterization of a small supernumerary Marker Chromosome (sSMC) derived from Chromosome 11. Case report: A 37-year-old, gravida 3, para 2, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XX,+mar[18]/46,XX[4]. The parental karyotypes were normal. Level II ultrasound findings were unremarkable. Array comparative genomic hybridization (aCGH) on the DNA extracted from cultured amniocytes revealed no genomic imbalance. The sSMC was characterized by spectral karyotyping (SKY) using 24-color SKY probes and fluorescence in situ hybridization (FISH) using a whole Chromosome paint (wcp) probe and a CEP11 (D11Z1) probe. The result was 47,XX,+mar.ish(11)(SKY+, wcp11+, D11Z1+)[16]/46,XX[4], indicating that the sSMC was derived from Chromosome 11. A healthy female baby was delivered at 37 weeks of gestation with no phenotypic abnormalities. The cord blood had a karyotype of 47,XX,+mar[32]/46,XX[8]. Polymorphic DNA Marker analysis of the blood excluded uniparental disomy 11. The female infant was normal in growth and psychomotor development during follow-ups at two months of age. Conclusion: aCGH, SKY and FISH are useful in prenatal diagnosis of an sSMC derived from the centromeric region of a non-acrocentric Chromosome

  • Prenatal diagnosis and molecular cytogenetic characterization of concomitant familial small supernumerary Marker Chromosome derived from Chromosome 4q (4q11.1–q13.2) and 5q13.2 microdeletion with no apparent phenotypic abnormality
    Elsevier, 2017
    Co-Authors: Chihping Chen, Yenni Chen, Schu-rern Chern, Shin-wen Chen, Chen-wen Pan, Chienwen Yang, Chen-chi Lee, Meng-shan Lee, Wayseen Wang
    Abstract:

    Objective: We present prenatal diagnosis and molecular cytogenetic characterization of concomitant familial small supernumerary Marker Chromosome 4 [sSMC(4)] derived from 4q11.1–q12 and q13.2, and 5q13.2 microdeletion with no apparent phenotypic abnormality. Materials and methods: A 32-year-old woman underwent amniocentesis at 21 weeks of gestation because of absent nasal bone on fetal ultrasound. Amniocentesis revealed a karyotype of 47,XX,+mar[13]/46,XX[3]. Array comparative genomic hybridization analysis on the cultured amniocytes revealed a 2.752-Mb duplication at 4q11–q12, a 1.949-Mb duplication at 4q13.2, and a 1.65-Mb deletion at 5q13.2. The woman underwent repeat amniocentesis at 24 weeks of gestation for molecular cytogenetic characterization. The phenotypically normal parents and their elder son underwent genetic analysis. Results: At repeat amniocentesis, interphase fluorescence in situ hybridization analysis on uncultured amniocytes revealed 79.25% (84/106) mosaicism for the sSMC(4), and metaphase fluorescence in situ hybridization analysis on cultured amniocytes revealed that all 20 cells examined (100%) had the sSMC(4). Polymorphic DNA Marker analysis on uncultured amniocytes excluded uniparental disomy 4. The father had a karyotype of 47,XY,+mar[2]/46,XY[38], and interphase fluorescence in situ hybridization revealed 2.91% (3/103) mosaicism for the sSMC(4) in his peripheral blood. The mother carried the 5q13.2 microdeletion. The elder son had a karyotype of 47,XY,+mar[27]/ 46,XY[13] with duplications of 4q11–q12 and 4q13.2. A 3105 g female baby was delivered at term with no apparent phenotypic abnormality. Conclusion: Prenatal diagnosis of concomitant sSMC and microdeletion should raise a suspicion of familial inheritance

  • molecular cytogenetic characterization of mosaicism for a small supernumerary Marker Chromosome derived from Chromosome 8 or r 8 p12 q13 1 associated with phenotypic abnormalities
    Taiwanese Journal of Obstetrics & Gynecology, 2016
    Co-Authors: Chihping Chen, Yenni Chen, Schu-rern Chern, Wayseen Wang, Shin-wen Chen, Chienwen Yang, Wen Lin Chen, Shuanpei Lin, Yi Hui Lin
    Abstract:

    Abstract Objective We present molecular cytogenetic characterization of mosaicism for a small supernumerary Marker Chromosome (sSMC) derived from Chromosome 8. Materials and Methods A 35-year-old woman underwent amniocentesis at 16 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 47,XY,+mar[20]/46,XY[39]. However, array comparative genomic hybridization analysis on the subcultured amniocytes revealed no genomic imbalance. Prenatal ultrasound showed bilateral ventriculomegaly, intrauterine growth restriction, and an enlarged right atrium. At 36 weeks of gestation, a 2380-g baby was delivered with mild facial dysmorphism. The baby postnatally manifested right hydronephrosis, vesicoureteral reflux, hypospadias, hypotonia, strabismus, developmental delay and mild mental retardation. Array comparative genomic hybridization and metaphase fluorescence in situ hybridization analyses were performed on the peripheral blood to determine the origin and mosaicism of the sSMC, and quantitative fluorescent polymerase chain reaction was used to exclude uniparental disomy. Results The blood had a karyotype of 47,XY,+mar[17]/46,XY[23]. Array comparative genomic hybridization revealed arr 8p12q13.1 (33,476,753–67,428,722) × 2.40 (Log2 ratio = 0.24) encompassing 98 Online Mendelian Inheritance in Man (OMIM) genes including CHD7, consistent with 30–40% mosaicism for r(8)(::p12→q13.1::). Metaphase fluorescence in situ hybridization identified the sSMC(8) in 21/33 of cultured lymphocytes. Quantitative fluorescent polymerase chain reaction excluded uniparental disomy 8. Conclusion Mosaic sSMC(8) derived from r(8)(::p12→q13.1::) can present phenotypic abnormalities. Chromosome 8q12 duplication syndrome should be included in differential diagnosis when an sSMC(8) contains 8q12.2 and CHD7.

Thomas Liehr - One of the best experts on this subject based on the ideXlab platform.

  • typical and partial cat eye syndrome identification of the Marker Chromosome by fish
    Clinical Genetics, 2008
    Co-Authors: Thomas Liehr, R A Pfeiffer, Udo Trautmann
    Abstract:

    Three children are reported with typical cat eye syndrome (CES) and three more children with partial CES because of absence of coloboma, in which the supernumerary Marker Chromosome was studied by FISH. Using a genomic library, and also a centromeric and particularly a cosmid probe of 22q11, partial tetrasomy was shown in all cases.

  • paternal uniparental isodisomy for Chromosome 14 with mosaicism for a supernumerary Marker Chromosome 14
    American Journal of Medical Genetics Part A, 2007
    Co-Authors: Thomas Liehr, Joerg Mattes, Bruce Whitehead, Ian Wilkinson, John Bear, Kerry Fagan, Paul Craven, Bruce Bennetts
    Abstract:

    Uniparental disomy (UPD) describes the inheritance of two homologous Chromosomes from a single parent. Disease phenotypes associated with UPD and chromosomal imprinting, rather than with mutations, include Beckwith-Wiedemann syndrome (paternal UPD11p), Angelman syndrome (paternal UPD15), Prader-Willi syndrome (maternal UPD15), and transient neonatal diabetes (paternal UPD6). Here we report on the first case of paternal uniparental isodisomy of Chromosome 14 with a mosaicism for a supernumerary Marker Chromosome 14. The patient demonstrated a small thorax with a 'coat hanger' shape of the ribs, kyphoscoliosis, hypoplasia of the maxilla and mandible, a broad nasal bridge with anteverted nares, contractures of the wrists with ulnar deviation bilaterally, diastasis recti, and marked muscle hypotonia. Vertical skin creases under the chin and stippled epiphyses of the humeri were features not previously described in patients with paternal UPD14. This case illustrates that as with the finding of an isoChromosome, a supernumerary Marker Chromosome can be an important clue to the presence of UPD14.

  • a further case with a small supernumerary Marker Chromosome ssmc derived from Chromosome 1 evidence for high variability in mosaicism in different tissues of ssmc carriers
    Prenatal Diagnosis, 2007
    Co-Authors: Ina Fickelscher, Heike Starke, Eberhard Schulze, Gunther Ernst, Nadezda Kosyakova, Hasmik Mkrtchyan, Kay Macdermont, N J Sebire, Thomas Liehr
    Abstract:

    A prenatally ascertained case with a de novo small supernumerary Marker Chromosome (sSMC) derived from Chromosome 1 is reported. Due to a fetal heart defect the parents decided in favour of an induced abortion. Postmortem, a molecular cytogenetic study on eleven formalin fixed, paraffin-embedded tissues of the fetus was performed, to further characterize the levels of mosaicism of the sSMC(1). sSMC presence varied between 13 and 62% within different tissues of sSMC carriers. This finding is something common in sSMC carriers and could explain why up to the present no clinical correlations for sSMC mosaicism and clinical outcome in the corresponding carriers could be established.

  • 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
    Cytogenetic and Genome Research, 2003
    Co-Authors: Iris Bartels, Heike Starke, Thomas Liehr, G Schlueter, F Von Eggeling, R Glaubitz, Peter Burfeind
    Abstract:

    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.

  • Molecular cytogenetic characterization of a prenatally detected supernumerary minute Marker Chromosome 8
    Prenatal Diagnosis, 1999
    Co-Authors: Heike Starke, Isolde Schreyer, Christine Kähler, Volkmar Beensen, Angela Nietzel, Anita Heller, Uwe Claussen, Wolfgang Fiedler, Thomas Liehr
    Abstract:

    : The characterization of a prenatally detected very small (approximately half of 18p-(karyotype: 47,XX,+mar[16]/46,XX[7]) supernumerary Marker Chromosome (SMC) identified by GTG-banding analysis is described. The Marker has been identified as derived from Chromosome 8 centromeric material using a combination of different cytogenetic (GTG-, NOR-, CBG banding), molecular cytogenetic (24 colour-fluorescent in situ hybridization [FISH], three-colour FISH using centromeric probes for all human Chromosomes) and molecular genetic techniques (microsatellite analysis). This is the first case described with such a minute SMC derived from Chromosome 8 diagnosed prenatally, the 15th case reporting on a SMC originating from Chromosome 8 and the third such case without any severe clinical features.

Harold Bass - One of the best experts on this subject based on the ideXlab platform.

  • A systematic analysis of small supernumerary Marker Chromosomes using array CGH exposes unexpected complexity
    Genetics in Medicine, 2013
    Co-Authors: Kavita S. Reddy, Swaroop Aradhya, Jeanne Meck, George Tiller, Sridevi Abboy, Harold Bass
    Abstract:

    Genet Med 2013:15(1):3–13 Purpose: A small supernumerary Marker Chromosome is often seen in patients with developmental disorders. Prior to array-based comparative genomic hybridization Markers were rarely genotyped end to end. In this study, a valid genotype-to-phenotype correlation was possible because the supernumerary Marker Chromosomes were fully characterized by array-based comparative genomic hybridization in a genome-wide analysis. Methods: Ten consecutive de novo small supernumerary Marker Chromosome cases were systematically genotyped using G-banding, C-banding, AgNOR staining, whole-genome array-based comparative genomic hybridization, and fluorescence in situ hybridization. Results: Among 10 small supernumerary Marker Chromosome cases studied, 4 (40%) were not identified by array-based comparative genomic hybridization because of low-level mosaicism or because they lacked euchromatin. One case (10%) was a simple pericentromeric Marker extending from 5p13.3 to 5q11.2. Five (50%) Markers showed unexpected complexity. Two cases had Markers that were derivative acrocentric (AgNOR+) Chromosomes with the euchromatin from Chromosomes 18p or 19p. Each of the other three cases with complex Markers had unusual characteristics including a Marker from noncontiguous segments of Chromosome 19q, a highly complex rearrangement involving a Chromosome 20 homolog as well as the small supernumerary Marker Chromosome, and a mosaic duplication of a proximal 8p Marker. Conclusion: Small supernumerary Marker Chromosomes are frequently complex on the basis of our small sample. Whole-genome array-based comparative genomic hybridization characterization of the small supernumerary Marker Chromosome provided informed genetic counseling.

  • A systematic analysis of small supernumerary Marker Chromosomes using array CGH exposes unexpected complexity
    Genetics in Medicine, 2013
    Co-Authors: Kavita S. Reddy, Swaroop Aradhya, Jeanne Meck, George Tiller, Sridevi Abboy, Harold Bass
    Abstract:

    Genet Med 2013:15(1):3–13 Purpose: A small supernumerary Marker Chromosome is often seen in patients with developmental disorders. Prior to array-based comparative genomic hybridization Markers were rarely genotyped end to end. In this study, a valid genotype-to-phenotype correlation was possible because the supernumerary Marker Chromosomes were fully characterized by array-based comparative genomic hybridization in a genome-wide analysis. Methods: Ten consecutive de novo small supernumerary Marker Chromosome cases were systematically genotyped using G-banding, C-banding, AgNOR staining, whole-genome array-based comparative genomic hybridization, and fluorescence in situ hybridization. Results: Among 10 small supernumerary Marker Chromosome cases studied, 4 (40%) were not identified by array-based comparative genomic hybridization because of low-level mosaicism or because they lacked euchromatin. One case (10%) was a simple pericentromeric Marker extending from 5p13.3 to 5q11.2. Five (50%) Markers showed unexpected complexity. Two cases had Markers that were derivative acrocentric (AgNOR+) Chromosomes with the euchromatin from Chromosomes 18p or 19p. Each of the other three cases with complex Markers had unusual characteristics including a Marker from noncontiguous segments of Chromosome 19q, a highly complex rearrangement involving a Chromosome 20 homolog as well as the small supernumerary Marker Chromosome, and a mosaic duplication of a proximal 8p Marker. Conclusion: Small supernumerary Marker Chromosomes are frequently complex on the basis of our small sample. Whole-genome array-based comparative genomic hybridization characterization of the small supernumerary Marker Chromosome provided informed genetic counseling.

Albert Schinzel - One of the best experts on this subject based on the ideXlab platform.

  • maternal uniparental isodisomy 10 and mosaicism for an additional Marker Chromosome derived from the paternal Chromosome 10 in a fetus
    Prenatal Diagnosis, 2002
    Co-Authors: Monika Schlegel, Mariluce Riegel, Alessandra Baumer, Ute Wiedemann, Albert Schinzel
    Abstract:

    An Erratum has been published for this article in Prenatal Diagnosis 22(11) 2002: 1056. We report a case of maternal isodisomy 10 combined with mosaic partial trisomy 10 (p12.31-q11.1). Chromosome examinations from a CVS sample showed a karyotype 47,XY,+mar/46,XY. The additional Marker Chromosome which was present in 6/25 interphase nuclei was shown by fluorescence in situ hybridization (FISH) to have been derived from a pericentromeric segment of Chromosome 10. DNA analysis was performed from umbilical cord blood from the fetus after termination of the pregnancy at 18 weeks. The results showed that the two structurally normal Chromosomes 10 were both of maternal origin, whereas the Marker Chromosome derived from the father. Autopsy of the fetus revealed hypoplasia of heart, liver, kidneys and suprarenal glands, but, apart from a right bifid ureter, no structural organ abnormalities. This fetus represents the second reported instance of a maternal uniparental disomy (UPD) 10. Copyright © 2002 John Wiley & Sons, Ltd.

  • A supernumerary Marker Chromosome originating from two different regions of Chromosome 18
    Journal of Medical Genetics, 2000
    Co-Authors: Benno Röthlisberger, Damina Balmer, Krystyna H. Chrzanowska, Mariluce Riegel, Albert Schinzel
    Abstract:

    By random amplification of a microdissected Chromosome using the degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) and forward painting (microFISH), we characterised an extra structurally abnormal Chromosome (ESAC) or supernumerary Marker Chromosome in a mentally retarded girl with a pattern of dysmorphic features. It could be clearly shown that the small Marker Chromosome originates from two different regions of Chromosome 18, 18p11.1→18q11.1 and 18q12.3→18q21.1 respectively. Maternal origin of the de novo ESAC and biparental origin of the normal homologues of Chromosome 18 were shown by PCR of several highly polymorphic microsatellites. In this case, application of microFISH was a prerequisite for rapid and precise characterisation of an ESAC. A definite identification of this discontinuous supernumerary Marker Chromosome would not have been possible using FISH with centromere specific probes or multicolour FISH approaches. Keywords: supernumerary Marker Chromosome; microdissection; FISH; Chromosome 18

Elisabeth Blennow - One of the best experts on this subject based on the ideXlab platform.

  • inherited mosaicism for the supernumerary Marker Chromosome in cat eye syndrome inter and intra individual variation and correlation to the phenotype
    American Journal of Medical Genetics Part A, 2012
    Co-Authors: Malin Kvarnung, Anna Lindstrand, Helena Malmgren, Anders Thastrom, Lena Jacobson, Niklas Dahl, Johanna Lundin, Elisabeth Blennow
    Abstract:

    We have studied a family with repeated transmission of mosaicism for a supernumerary Marker Chromosome (SMC), giving rise to varying symptoms of the cat eye syndrome (CES) in the offspring. The frequency of the SMC was investigated using FISH with probes from the CES critical region on lymphocytes as well as buccal cells. The same probes were used to study the frequency of the SMC in spermatozoa from the father. The SMC was characterized in detail using array-CGH and was found to correspond to a symmetrical cat eye SMC type I, with two extra copies of the most proximal part of 22q11, not extending into the classical 22q11.2 deletion region. Mosaicism for the SMC was detected in 4 out of 7 family members, the father and all his three children. The degree of mosaicism varied greatly between individuals as well as between tissues, with twice as many cells with the SMC in epithelial cells compared to blood. The highest frequency (almost 50%) was found in spermatozoa from the father. There was a direct correlation between the degree of mosaicism and the symptoms, varying from no obvious symptoms to classical CES. The study confirms the occurrence of direct transmission of SMC-mosaicism in CES. The results indicate that examination of parental epithelial cells should be preferred compared to blood cells in order to exclude a recurrence risk in parents of a child with CES. Interphase FISH analysis of spermatozoa is the most sensitive method to exclude paternal germ line mosaicsm. (c) 2012 Wiley Periodicals, Inc.

  • molecular identification of a small supernumerary Marker Chromosome by in situ hybridization diagnosis of an isoChromosome 18p with probe l1 84
    Clinical Genetics, 2008
    Co-Authors: Elisabeth Blennow, Karen Brondum Nielsen
    Abstract:

    : A dysmorphic child was found by cytogenetic analysis to have an extra small Marker Chromosome. The Marker Chromosome was shown to possess a Chromosome 18 centromere by in situ hybridization, and probably represents an isoChromosome 18p. Centromere specific probes should be of value in identifying extra small Marker Chromosomes, and thereby provide better understanding of the clinical significance of these.

  • Tetrasomy 15q: two Marker Chromosomes with no detectable alpha-satellite DNA.
    American journal of human genetics, 1994
    Co-Authors: Elisabeth Blennow, Catharina Larsson, Håkan Telenius, D. De Vos, P. Henriksson, O. Johansson, Nigel P. Carter, Magnus Nordenskjold
    Abstract:

    Two patients with specific and similar phenotypes were both found to have an unusual Marker Chromosome present in 70%-80% of their lymphocytes at routine cytogenetic examination. The Marker Chromosomes were isolated by flow sorting and were amplified by degenerate oligonucleotide-primed PCR. These libraries and a cosmid probe located at 15q26 were used to characterize the Marker Chromosomes by FISH. Both Marker Chromosomes were found to consist of duplicated Chromosome material from the distal part of Chromosome 15q and were identified as inv dup(15) (qter-->q23::q23-->qter) and inv dup(15) (qter-->q24::q24-->qter), respectively. Hence, the Markers did not include any known centromere region, and no alpha-satellite DNA could be detected at the site of the primary constriction. Tetrasomy 15q may be a new syndrome, associated with a specific type of Marker Chromosome. In addition, further analyses of this type of Marker Chromosome might give new insight into the structure and function of the mammalian centromere.

  • Complete characterization of a large Marker Chromosome by reverse and forward Chromosome painting
    Human Genetics, 1992
    Co-Authors: Elisabeth Blennow, Svetlana Bajalica, Catharina Larsson, Håkan Telenius, Bruce A.j. Ponder, Magnus Nordenskjold
    Abstract:

    Marker Chromosome are small supernumerary Chromosomes that are sometimes associated with developmental abnormalities. Hence, the genes involved in such cases provide an interesting approach to understanding developmental abnormalities in man. As a first step towards isolating such sequences, Marker Chromosomes need complete characterization. By combining Chromosome isolation by flow sorting and the “degenerate oligonucleotide primed — polymerase chain reaction”, we have constructed a DNA library specific for a Marker Chromosome found in a child with severe developmental abnormalities. We used fluorescent in situ hybridization of the library onto normal metaphase spreads (“reverse Chromosome painting“) and were thus able to determine that the Marker consists of the centromeric part of Chromosome 7, the telomeric region of the long arm of Chromosome 5 and the telomeric region of the short arm of the X-Chromosome. Subsequently, we hybridized normal Chromosome-specific libraries of the relevant Chromosomes onto metaphases containing the Marker Chromosome (“forward Chromosome painting”) and could in this manner establish the precise location of the different Chromosome regions on the Marker Chromosome itself. This is a general approach suitable for outlining Marker Chromosomes in detail, and will aid the identification of the genes involved.