Molecular analysis in Turner syndrome

Álvarez-Nava, Francisco; Soto, Marisol; Sánchez, María Dolores Martín; Fernández, Erika; Lanes, Roberto

doi:10.1067/mpd.2003.95

Cited by 58 publications

(47 citation statements)

References 32 publications

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“…7 Although the use of flow cytometry or DNA hybridization to search for Y-chromosome material has been suggested for all girls with a 45,X karyotype, 8 clinical evidence indicates that such an approach is merited only in those with masculinization or mosaicism for an unidentified marker. The use of polymerase-chain-reaction testing for Y-chromosome sequences has a high false positive rate.…”

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confidence: 99%

Turner's Syndrome

2004

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mentioning

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Turner's Syndrome

2004

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“…Las series reportan la monosomía del X hasta en 50% de los casos, a diferencia de lo reportado por Nielsen y Wohlert (5), quienes encontraron la fórmula cromosómica 45,X presente solo en 1 de cada 9 casos de ST mientras los restantes correspondían a mosaicos y anormalidades de X. Se considera que la detección de material correspondiente al cromosoma Y es cada vez mayor debido al uso más frecuente de técnicas como FISH, lo cual podría significar que la verdadera incidencia de este fenómeno entre pacientes con ST puede llegar a ser del 10 al 15% (4,8). En pacientes con signos de androgenización y presencia del cromosoma Y completo o fragmentos de este, confirmada con cariotipo o FISH, deben realizarse estudios imagenológicos de extensión, idealmente RMN, para descartar la presencia de estría gonadal, puesto que ésta se relaciona con el desarrollo de un raro tumor, el gonadoblastoma; lo cual obliga a su resección quirúrgica (4).…”

Section: Caso Clínicounclassified

Síndrome De Turner Con Mosaicismo 45x/46xy: Reporte De Caso

Saldarriaga

Sánchez

Lourido

2011

Rev. chil. obstet. ginecol.

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RESUMENEl síndrome de Turner tiene una prevalencia de 1 en 1800 a 5000 recién nacidos vivos femeninos y se caracteriza por la ausencia total o parcial del segundo cromosoma X. Actualmente se reconoce gran variedad en la presentación citogenética, siendo la más común la monosomia del X (45,X) y entre las menos frecuentes los mosaicismos que incluyen fragmentos o la totalidad del cromosoma Y. La presencia de este cromosoma confiere características fenotípicas de androgenización y obliga a la realización de estudios de extensión en las pacientes. Se reporta un caso de síndrome de Turner con mosaicismo 45,X/46,XY, se revisa la literatura y se propone un protocolo de estudio complementario y manejo de las pacientes con este síndrome.PALABRAS CLAVE: Síndrome de Turner, variación citogenética, fenotipo, mosaicismo SUMMARY Turner syndrome has an estimated prevalence of 1 in 1800 to 5000 female births and is characterized by total or partial absence of the second chromosome X. It's now recognized that there is variation in the cytogenetic presentation of the syndrome, being the most common monosomy X (45, X) and among the least frequent it's found mosaicism including fragments or the entire Y chromosome. The presence of Y chromosome confers phenotypic characteristics of androgenization and requires extension studies in patients. We report a case of Turner syndrome with mosaic 45,X/46,XY karyotype found by G-banding and aditionally, we propose a protocol for further studies and management of patients with this syndrome.Key words: Turner's syndrome, cytogenetic variation, phenotype, mosaicism INTRODUCCIÓNEl síndrome de Turner (ST) es una condición genética caracterizada por la ausencia total o parcial del segundo cromosoma X. Su prevalencia oscila entre 1 en 1800 a 5000 recién nacidos vivos femeninos, atribuyéndose las diferencias entre prevalencias estimadas, a la población estudiada y el momento del análisis cromosómico, sin embargo, se estima que representa hasta el 3% de todas las concepciones (1).La forma mas frecuente de presentación citogenética es 45X, sin embargo, alrededor del 50% de los pacientes presentan una formula cromosómica diferente. La variedad 45,X/46,XY es de las de menor frecuencia y esta reportada en cerca del 5% de

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“…12 Two studies compared methods to identify sex chromosome mosaicism in UTS patients but neither demonstrated that PCR analysis identified XY mosaicism that would not have been detected using karyotype and FISH analysis. Alvarez-Nava et al 13 identified 4/52 patients with Y-chromosome material. Two patients had a 45,X/46,XY karyotype, and one had a Yderived marker chromosome identified by FISH.…”

Section: Fish Analysis In Ullrich-turner Syndrome Patientsmentioning

confidence: 99%

FISH analysis helps identify low-level mosaicism in Ullrich-Turner syndrome patients

Wiktor

Dyke

2004

Genetics in Medicine

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Purpose: To search for X or Y chromosome mosaicism in 45,X individuals using fluorescent in situ hybridization (FISH). Methods: From our series of 53 Ullrich-Turner syndrome patients, we used interphase FISH to evaluate the 19 who had an apparently nonmosaic 45,X karyotype with G-banding. Results: Of those 19 patients, mosaicism was detected in seven (37%), five patients had an XX line, one had a monocentric isochromosome X, and one had The incidence of Ullrich-Turner syndrome (UTS) is approximately one in 3000 newborn girls and is associated with an apparently nonmosaic 45,X karyotype in many of these patients. 1 Fewer than 15% of UTS patients appear to have mosaicism with a 46,XY cell population or a Y chromosome rearrangement, and 30 -50% are mosaic with a second X or a structurally abnormal X. Up to 18% of patients have a small marker chromosome in some cells, the origin of which can be identified by FISH or other methods. 2 The mosaic status of the remaining UTS patients remains uncertain but of clinical interest because if they do have cells with a Y chromosome, they may have an increased risk of gonadoblastoma. The American College of Medical Genetics recommends cytogenetic analysis of 30 metaphase cells in cases studied to rule out sex chromosome mosaicism. 3 This analysis can identify 10% mosaicism with a confidence level of 95%, but a more sensitive level of detection would require costly analysis of many more metaphase cells. PCR-based assays can be used to identify low-level mosaicism but has limitations 4 -7 including a high rate of falsepositive results with nested PCR. 8,9 In this study, we report the results of karyotype and FISH analysis in 53 patients with monosomy X or monosomy X mosaicism. MATERIALS AND METHODSBetween January 1997 and August 2003, we studied 53 samples submitted for karyotype analysis based on phenotypic features suggestive of UTS in which the karyotype results included a 45,X cell line. We excluded females suspected of having UTS who had a nonmosaic 46,XX karyotype. Several blood samples were sent to confirm a prenatal diagnosis of UTS were included.G-banded metaphase analysis from PHA-stimulated lymphocyte cultures was performed. A minimum of 30 metaphase cells was analyzed in cases with a nonmosaic 45,X karyotype, or a minimum of 20 metaphase cells when mosaicism was identified by the 20th cell.FISH testing was performed on all 19 cases with an apparently nonmosaic 45,X karyotype. Using centromere probes for the X (DXZ1) and Y chromosomes (DYZ3) (Vysis, Inc., Downer's Grove, IL), a minimum of 200 interphase cells were scored. A male control was hybridized concurrently with each sample and the intensity of the Y signal was used to discriminate between a true "Y" signal and an artifact signal. If the initial analysis was equivocal (one cell with both X and Y signals), an additional 300 cells were analyzed. Cases demonstrating one XX signal (of 200 cells) or one XY signal (of Ͼ 500 cells) were considered nonmosaic, whereas those with Ͼ 1% XX cells were identified as true mosa...

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Molecular analysis in Turner syndrome

Cited by 58 publications

References 32 publications

Turner's Syndrome

Turner's Syndrome

Síndrome De Turner Con Mosaicismo 45x/46xy: Reporte De Caso

FISH analysis helps identify low-level mosaicism in Ullrich-Turner syndrome patients

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