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Santos M, Mrasek K, Madrigal I, Martorell MR, González-Meneses A, Rodríguez-Criado G, Milà M, Liehr T, Fuster C. Characterization of a complex cryptic mosaicism for an sSMC derived from the X chromosome present in a boy with congenital malformations. Am J Med Genet A 2010; 152A:2661-3. [PMID: 20814948 DOI: 10.1002/ajmg.a.33638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- M Santos
- Unitat de Biologia Cel lular i Genètica Mèdica, Facultat de Medicina, Universitat Autònoma de Barcelona, Servei de Bioquímica i Genètica Molecular, Hospital Clínic de Barcelona, Barcelona, Spain
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Supernumerary marker chromosome 15 in a male with azoospermia and open bite deformity. Asian J Androl 2009; 11:617-22. [PMID: 19701220 DOI: 10.1038/aja.2009.37] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Supernumerary marker chromosome 15 (sSMC[15]) is the most frequent marker chromosome, and it is generally regarded as unimportant if it does not contain the Prader-Willi/Angelman syndrome critical region (PWACR). The clinical importance of the larger markers in association with the critical region is mentioned in almost all reports related to marker chromosome 15, and smaller markers are solely associated with minor dysmorphic features, azoospermia and recurrent miscarriages. However, these small sSMC(15)s without the PWACR may also determine a specific phenotype. A dysmorphic examination of an azoospermic patient in a genetics clinic was performed and was followed by a peripheral blood lymphocyte chromosomal analysis according to standard cytogenetic methods. Nucleolar region (NOR) banding, C-banding, fluorescence in situ hybridization and a molecular investigation of Y-microdeletions were also performed. The clinical evaluation identified dysmorphic features accompanied with azoospermia and severe 'Angle Class II, Division 1 Open Bite Deformity'. The molecular cytogenetic study revealed the small sSMC(15). In addition, a Y-microdeletion analysis showed that the azoospermia was not the result of a deletion. Although the presented case might represent a coincidental example of supernumerary marker 15 and mandibular anomaly association, the condition may also define a specific phenotype that may be more than azoospermia. This condition may be characterized by infertility, malar hypoplasia, mandibular anomaly, keloid formation and minor dysmorphic features.
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Hunter M, Bruno D, Amor DJ. Functional disomy of proximal Xp causes a distinct phenotype comprising early hypotonia, hypertelorism, small hands and feet, ear abnormalities, myopia and cognitive impairment. Am J Med Genet A 2009; 149A:1763-7. [DOI: 10.1002/ajmg.a.32954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chen CP, Lin SP, Lin CC, Li YC, Hsieh LJ, Chern SR, Lee CC, Chen LF, Hua HM, Wang W. Prenatal diagnosis of low-level mosaicism for a small XIST-negative supernumerary ring X chromosome in a nondysmorphic male fetus. Prenat Diagn 2006; 26:387-91. [PMID: 16566039 DOI: 10.1002/pd.1416] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Liehr T, Mrasek K, Weise A, Dufke A, Rodríguez L, Martínez Guardia N, Sanchís A, Vermeesch JR, Ramel C, Polityko A, Haas OA, Anderson J, Claussen U, von Eggeling F, Starke H. Small supernumerary marker chromosomes – progress towards a genotype-phenotype correlation. Cytogenet Genome Res 2005; 112:23-34. [PMID: 16276087 DOI: 10.1159/000087510] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Accepted: 04/19/2005] [Indexed: 11/19/2022] Open
Abstract
Small supernumerary marker chromosomes (sSMC) are still a major problem in clinical cytogenetics as they are too small to be characterized for their chromosomal origin by traditional banding techniques, but require molecular cytogenetic techniques for their identification. Apart from the correlation of about one third of the sSMC cases with a specific clinical picture, i.e. the i(18p), der(22), i(12p) (Pallister Killian syndrome) and inv dup(22) (cat-eye) syndromes, most of the remaining sSMC have not yet been correlated with clinical syndromes. Recently, we reviewed the available >1600 sSMC cases (Liehr T, sSMC homepage: http://mti-n.mti.uni-jena.de/~huwww/MOL_ZYTO/sSMC.htm). A total of 387 cases (including the 45 new cases reported here) have been molecularly cytogenetically characterized with regard to their chromosomal origin, the presence of euchromatin, heterochromatin and satellite material. Based on analysis of these cases we present the first draft of a basic genotype-phenotype correlation for sSMC for all human chromosomes apart from the chromosomes Y, 10, 11 and 13.
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Affiliation(s)
- T Liehr
- Institut für Humangenetik und Anthropologie, Jena, Germany.
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Leppig KA, Sybert VP, Ross JL, Cunniff C, Trejo T, Raskind WH, Disteche CM. Phenotype and X inactivation in 45,X/46,X,r(X) cases. Am J Med Genet A 2005; 128A:276-84. [PMID: 15216549 DOI: 10.1002/ajmg.a.30002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We studied a new series of 21 individuals mosaic for a ring X chromosome [r(X)]. Of nine individuals with mental retardation, only one had a r(X) that lacked XIST (X-inactive-specific transcript) and was not subject to X inactivation, which would explain the abnormal phenotype; the remaining eight cases had XIST on their r(X). The majority of cases (five of seven) with mental retardation had an apparently early replicating r(X); but the androgen receptor gene (AR) was methylated on one allele in five of six informative cases, including two cases with an early replicating r(X). These conflicting results on two indicators of X inactivation suggest a potential dissociation between late replication and DNA methylation in these r(X) chromosomes, which may fail to become completely silenced. Of the twelve subjects who were not mentally retarded, all had XIST present on their r(X) and most (8/10) showed a late replicating r(X), together with AR methylation in all five informative cases, indicating r(X) inactivation. Thus, the unusual phenotypic features and mental retardation associated with the presence of a r(X) cannot be explained solely on the basis of presence or absence of XIST. The r(X) in cases with mental retardation were consistently smaller than those in individuals with normal intelligence, perhaps indicating inability for small rings to undergo structural changes associated with complete X inactivation or lethality in cases with a large non-inactivated r(X). Of the Turner syndrome features present in the r(X) cases, only edema was present in a lesser frequency than in 45,X individuals. Our cases generally had a less severe phenotype than those previously reported, suggesting that reported incidences of abnormalities may be influenced by ascertainment bias, with mental retardation potentially unrelated to the presence of the r(X) in some cases.
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MESH Headings
- Adolescent
- Adult
- Cells, Cultured
- Child
- Child, Preschool
- Chromosomes, Human, X/genetics
- Chromosomes, Human, X/metabolism
- DNA Methylation
- DNA Replication/genetics
- Dosage Compensation, Genetic
- Gene Expression
- Humans
- In Situ Hybridization, Fluorescence
- Infant
- Intellectual Disability/genetics
- Karyotyping
- Lymphocytes/chemistry
- Middle Aged
- Phenotype
- RNA, Long Noncoding
- RNA, Messenger/analysis
- RNA, Untranslated/genetics
- Receptors, Androgen/genetics
- Ring Chromosomes
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Affiliation(s)
- Kathleen A Leppig
- Genetic Services, Group Health Permanente, Seattle, Washington 98112, USA.
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Le Caignec C, Boceno M, Joubert M, Winer N, Aubron F, Fallet-Bianco C, Rival JM. Prenatal diagnosis of a small supernumerary, XIST-negative, mosaic ring X chromosome identified by fluorescence in situ hybridization in an abnormal male fetus. Prenat Diagn 2003; 23:143-5. [PMID: 12575022 DOI: 10.1002/pd.553] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Marker or ring X [r(X)] chromosomes of varying size are often found in patients with Turner syndrome. Patients with very small r(X) chromosomes that did not include the X-inactivation locus (XIST) have been described with a more severe phenotype. Small r(X) chromosomes are rare in males and there are only five previous reports of such cases. We report the identification of a small supernumerary X chromosome in an abnormal male fetus. Cytogenetic analysis from chorionic villus sampling was performed because of fetal nuchal translucency thickness and it showed mosaicism 46,XY/47,XY,+r(X)/48,XY,+r(X),+r(X). Fluorescence in situ hybridizations (FISH) showed the marker to be of X-chromosome origin and not to contain the XIST locus. Additional specific probes showed that the r(X) included a euchromatic region in proximal Xq. At 20 weeks gestation, a second ultrasound examination revealed cerebral abnormalities. After genetic counselling, the pregnancy was terminated. The fetus we describe is the first male with a mosaic XIST-negative r(X) chromosome identified at prenatal diagnosis. The phenotype we observed was probably the result of functional disomy of the genes in the r(X) chromosome, secondary to loss of the XIST locus.
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Affiliation(s)
- C Le Caignec
- Service de Génétique médicale, Centre Hospitalo-Universitaire, CHU Nantes, 9 quai Moncousu, 44093 Nantes cedex, France.
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Tomkins DJ, McDonald HL, Farrell SA, Brown CJ. Lack of expression of XIST from a small ring X chromosome containing the XIST locus in a girl with short stature, facial dysmorphism and developmental delay. Eur J Hum Genet 2002; 10:44-51. [PMID: 11896455 DOI: 10.1038/sj.ejhg.5200757] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2001] [Revised: 11/21/2001] [Accepted: 11/22/2001] [Indexed: 02/07/2023] Open
Abstract
A 46,X,r(X) karyotype was found in a three and a half year old girl with short stature, facial dysmorphism and developmental delay. The clinical findings were consistent with the phenotype described in a limited number of patients with small ring X chromosomes lacking the XIST locus, a critical player in the process of X chromosome inactivation. Surprisingly, in our patient, fluorescent in situ hybridisation demonstrated that the XIST locus was present on the ring X. However, expression studies showed that there was no XIST transcript in peripheral blood cells, suggesting that the ring X had not been inactivated. This was confirmed by the demonstration that both of the patient's alleles for the androgen receptor gene were unmethylated, and that both of the patient's ZXDA alleles were expressed. The active nature of the ring X would presumably result in overexpression of genes that may account for the developmental delay observed for the patient. Using polymorphic markers along the X chromosome, the ring X was determined to be of paternal origin with one breakpoint in the long arm between DXS8037 and XIST and one in the short arm in Xp11.2 between DXS1126 and DXS991. To attempt to determine why the XIST gene failed to be expressed, the promoter region was sequenced and found to have a base change at the same location as a variant previously associated with nonrandom X chromosome inactivation. This mutation was not seen in over one hundred normal X chromosomes examined; however, it was observed in the paternal grandmother who did not show substantial skewing of X chromosome inactivation.
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Affiliation(s)
- Darrell J Tomkins
- Department of Medical Genetics, University of Alberta and Cytogenetics Laboratory, Stollery Children's Hospital, Edmonton, AB, Canada.
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Anderson CL, Brown CJ. Polymorphic X-chromosome inactivation of the human TIMP1 gene. Am J Hum Genet 1999; 65:699-708. [PMID: 10441576 PMCID: PMC1377976 DOI: 10.1086/302556] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
X inactivation silences most but not all of the genes on one of the two X chromosomes in mammalian females. The human X chromosome preserves its activation status when isolated in rodent/human somatic-cell hybrids, and hybrids retaining either the active or inactive X chromosome have been used to assess the inactivation status of many X-linked genes. Surprisingly, the X-linked gene for human tissue inhibitor of metalloproteinases (TIMP1) is expressed in some but not all inactive X-containing somatic-cell hybrids, suggesting that this gene is either prone to reactivation or variable in its inactivation. Since many genes that escape X inactivation are clustered, we examined the expression of four genes (ARAF1, ELK1, ZNF41, and ZNF157) within approximately 100 kb of TIMP1. All four genes were expressed only from the active X chromosome, demonstrating that the factors allowing TIMP1 expression from the inactive X chromosome are specific to the TIMP1 gene. To determine if this variable inactivation of TIMP1 is a function of the hybrid-cell environment or also is observed in human cells, we developed an allele-specific assay to assess TIMP1 expression in human females. Expression of two alleles was detected in some female cells with previously demonstrated extreme skewing of X inactivation, indicating TIMP1 expression from the inactive chromosome. However, in other cells, no expression of TIMP1 was observed from the inactive X chromosome, suggesting that TIMP1 inactivation is polymorphic in human females.
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Affiliation(s)
- C L Anderson
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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Clemson CM, Chow JC, Brown CJ, Lawrence JB. Stabilization and localization of Xist RNA are controlled by separate mechanisms and are not sufficient for X inactivation. J Cell Biol 1998; 142:13-23. [PMID: 9660859 PMCID: PMC2133021 DOI: 10.1083/jcb.142.1.13] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/1997] [Revised: 05/04/1998] [Indexed: 02/08/2023] Open
Abstract
These studies address whether XIST RNA is properly localized to the X chromosome in somatic cells where human XIST expression is reactivated, but fails to result in X inactivation (Tinker, A.V., and C.J. Brown. 1998. Nucl. Acids Res. 26:2935-2940). Despite a nuclear RNA accumulation of normal abundance and stability, XIST RNA does not localize in reactivants or in naturally inactive human X chromosomes in mouse/ human hybrid cells. The XIST transcripts are fully stabilized despite their inability to localize, and hence XIST RNA localization can be uncoupled from stabilization, indicating that these are separate steps controlled by distinct mechanisms. Mouse Xist RNA tightly localized to an active X chromosome, demonstrating for the first time that the active X chromosome in somatic cells is competent to associate with Xist RNA. These results imply that species-specific factors, present even in mature, somatic cells that do not normally express Xist, are necessary for localization. When Xist RNA is properly localized to an active mouse X chromosome, X inactivation does not result. Therefore, there is not a strict correlation between Xist localization and chromatin inactivation. Moreover, expression, stabilization, and localization of Xist RNA are not sufficient for X inactivation. We hypothesize that chromosomal association of XIST RNA may initiate subsequent developmental events required to enact transcriptional silencing.
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Affiliation(s)
- C M Clemson
- Department of Cell Biology, University of Massachusetts Medical Center, Worcester, Massachusetts 01655, USA.
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12
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Tinker AV, Brown CJ. Induction of XIST expression from the human active X chromosome in mouse/human somatic cell hybrids by DNA demethylation. Nucleic Acids Res 1998; 26:2935-40. [PMID: 9611238 PMCID: PMC147638 DOI: 10.1093/nar/26.12.2935] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
X chromosome inactivation occurs early in mammalian development to transcriptionally silence one of the pair of X chromosomes in females. The XIST RNA, a large untranslated RNA that is expressed solely from the inactive X chromosome, is implicated in the process of inactivation. As previous studies have shown that the XIST gene is methylated on the active X chromosome, we have treated a mouse/human somatic cell hybrid retaining an active human X chromosome with demethylating agents to determine whether expression of the human XIST gene could be induced. Stable expression of XIST was observed after several rounds of demethylation and stability of XIST expression correlated with the loss of methylation at the three sites analysed. We conclude that methylation is sufficient to inhibit expression of the XIST gene in somatic cell hybrids. No loss of expression was detected for eight other X-linked genes from the active X chromosome that was expressing XIST , suggesting that additional developmental or species-specific factors are required for the inactivation process.
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Affiliation(s)
- A V Tinker
- Department of Medical Genetics, University of British Columbia, 6174 University Boulevard, Vancouver, BC V6T 1Z3, Canada
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T�mer Z, Wolff D, Silahtaroglu AN, �rum A, Br�ndum-Nielsen K. Characterization of a supernumerary small marker X chromosome in two females with similar phenotypes. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19980226)76:1<45::aid-ajmg8>3.0.co;2-o] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Manea SR, Gershin IF, Babu A, Willner JP, Desnick RJ, Cotter PD. Mosaicism for a small supernumerary ring X chromosome in a dysmorphic, growth-retarded male: mos47,XXY/48,XXY, +r(X). Clin Genet 1997; 52:432-5. [PMID: 9520254 DOI: 10.1111/j.1399-0004.1997.tb02564.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Supernumerary ring X [r(X)] chromosomes are often found in patients with Turner syndrome. The phenotypic effects of the r(X) chromosome are variable, and largely depend on the presence or absence of the X inactivation (XIST) locus. Ring(X) chromosomes in males are rare and have been previously reported in only four cases, with 47,XY, + r(X) or mos47,XY, +r(X)/46,XY karyotypes. These patients all had developmental delay and dysmorphic features. We describe a 2.5-year-old male patient with facial dysmorphia, growth retardation, microcephaly, global developmental delay, and microphallus. Cytogenetic analysis from peripheral blood lymphocytes and fibroblasts identified mosaicism for two cell lines: mos48,XXY, + r(?X)/47,XXY. Fluorescence in situ hybridization (FISH) with an X chromosome paint showed the ring chromosome to be X chromosome derived. This is the first case of an r(X) chromosome described in a 47,XXY patient. FISH analysis of the r(X) chromosome with an XIST probe showed that the XIST locus was absent. Functional disomy of genes in the r(X) chromosome most likely accounts for the abnormal phenotype in the proband.
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Affiliation(s)
- S R Manea
- Department of Human Genetics, Mount Sinai School of Medicine, New York, NY, USA
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Schwartz S, Depinet TW, Leana-Cox J, Isada NB, Karson EM, Park VM, Pasztor LM, Sheppard LC, Stallard R, Wolff DJ, Zinn AB, Zurcher VL, Zackowski JL. Sex chromosome markers: characterization using fluorescence in situ hybridization and review of the literature. AMERICAN JOURNAL OF MEDICAL GENETICS 1997; 71:1-7. [PMID: 9215760 DOI: 10.1002/(sici)1096-8628(19970711)71:1<1::aid-ajmg1>3.0.co;2-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescence in situ hybridization (FISH) using biotin labeled X- and Y-chromosome DNA probes was utilized in the analysis of 23 sex chromosome-derived markers. Specimens were obtained through prenatal diagnosis, because of a presumptive diagnosis of Ullrich-Turner syndrome, mental retardation, and minor anomalies or ambiguous genitalia; three were spontaneous abortuses. Twelve markers were derived from the X chromosome and eleven from the Y chromosome; this demonstrates successfully the value and necessity of FISH utilizing DNA probes in the identification of sex chromosome markers. Both fresh and older slides, some of which had been previously G-banded, were used in these determinations. We have also reviewed the literature on sex chromosome markers identified using FISH.
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Affiliation(s)
- S Schwartz
- Center for Human Genetics, Department of Genetics, Case Western Reserve University, and University Hospitals of Cleveland, Ohio 44106, USA
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McGinniss MJ, Brown DH, Burke LW, Mascarello JT, Jones MC. Ring chromosome X in a child with manifestations of Kabuki syndrome. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1096-8628(19970502)70:1<37::aid-ajmg8>3.0.co;2-o] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Callen DF, Eyre HJ, Dolman G, Garry-Battersby MB, McCreanor JR, Valeba A, McGill JJ. Molecular cytogenetic characterisation of a small ring X chromosome in a Turner patient and in a male patient with congenital abnormalities: role of X inactivation. J Med Genet 1995; 32:113-6. [PMID: 7760319 PMCID: PMC1050231 DOI: 10.1136/jmg.32.2.113] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The association of small accessory marker chromosomes in man with specific abnormalities has been difficult to define owing to variations in the chromosome origin and the size of the markers. In a patient with typical Turner phenotype and a 45,X/46,X, + mar karyotype the marker was shown to be a small portion of the long arm of the X chromosome which included the centromere and XIST, a candidate gene for the X inactivation centre. Therefore the lack of any additional abnormalities was attributed to inactivation of the portion of the X chromosome in the marker. In a patient with a 47,XY, + mar karyotype the mar was a small ring X chromosome which did not contain the XIST gene. For both markers the short arm breakpoints were localised between UBE1 and DXS423E. The congenital abnormalities of the male patient were attributed to the lack of X inactivation of the small ring and therefore disomic expression of normal genes possessed by the marker.
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Affiliation(s)
- D F Callen
- Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, South Australia
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