1/44. Cri du chat and turner syndrome features in a newborn girl with an unbalanced 45,X,psu dic(5;X)(p15.2;p22.1) karyotype: FISH and replication banding studies.A newborn girl with features of Turner and Cri du chat syndromes was found to have a pseudodicentric 5;x chromosome. Her karyotype was 45,X, psu dic(5;X)(p15.2;p22.1). The net result was monosomy for 5p15.2-pter and Xp22.1-pter. fluorescence in situ hybridization (FISH) showed the Cri du chat region was deleted. Replication banding studies to assess the X-inactivation pattern found only the X portion of the pseudodicentric chromosome to be late replicating without any apparent spread of inactivation into chromosome 5 segment. There are only two cases reported with a dicentric X; autosome. In this paper, we compare the cytogenetics of the present case and those in the literature.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/44. Paternal sex chromosome aneuploidy as a possible origin of turner syndrome in monozygotic twins: case report.The meiotic or mitotic origin of most cases of turner syndrome remains unknown, due to the difficulty in detecting hidden mosaicisms and to the lack of meiotic segregation studies. We have had the opportunity to study one pair of monozygotic twins concordant for turner syndrome of paternal origin. The paternal origin of the single x chromosome was determined by polymerase chain reaction (PCR) amplification. No mosaicism was detected for the X or y chromosome. In this case, a meiotic error during gametogenesis would be a likely origin of X monosomy. To determine if meiotic errors are more frequent in the father of these monozygotic twins concordant for turner syndrome of paternal origin, molecular studies in spermatozoa were conducted to analyse sex chromosome numerical abnormalities. A total of 12520 sperm nuclei from the twins' father and 85338 sperm nuclei from eight normal donors were analysed using three-colour fluorescent in-situ hybridization. There were significant differences between the twins' father and control donors for XY disomy (0.22 versus 0.11%, P < 0.001) and total sex chromosome disomy (0.38 versus 0.21%, P < 0.001). These results could indicate an increased tendency to meiotic sex chromosome non-disjunction in the father of the Turner twins.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/44. Extensive cytogenetic studies of clonality following interferon-alpha therapy in chronic myeloid leukemia occurring in monosomic cells in a patient with turner syndrome mosaic.In a 27-year-old female with turner syndrome mosaic, philadelphia (Ph) chromosome-positive chronic myeloid leukemia (CML) occurred only in the monosomic cells (45, Xc). Extensive cytogenetic studies, including triple-color fluorescence in situ hybridization (FISH), revealed that Ph-positive monosomic cells (45, Xc), Ph-negative monosomic cells and normal diploid cells (46, XX) were present in her bone marrow at diagnosis. After successful interferon therapy, the non-leukemia cells expanded and reconstituted normal hematopoiesis resulting in complete cytogenetic response, following the selective suppression of the monosomic Ph-positive leukemia clone. The ratio of Xc to XX cells in bone marrow cells was significantly increased to that in skin fibroblasts. Moreover, the ratio of Ph-positive cells to Ph-negative cells was found to be significantly different between karyotyping and FISH. Studies of this quite unique case not only confirmed the clonality of CML, effectiveness of interferon-alpha and x chromosome imbalance among different tissues, but also demonstrated a discrepant increase of the BCR/ABL-positive clone in CML. The latter supports the hypothesis that reduced programmed cell death may be the primary mechanism responsible for the expansion of the leukemia clone in CML. Our study verifies the importance of extensive analysis of a neoplastic disease in patients with a constitutional chromosomal abnormality.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/44. Molecular mapping of an idic(Yp) chromosome in an Ullrich-Turner patient.We describe a woman with Ullrich-Turner manifestations and a 45,X/46, X, mar karyotype. fluorescence in situ hybridization (FISH) and DNA analysis were carried out in order to determine the origin and structure of the marker. FISH showed that the marker was a Y-derived dicentric chromosome. The breakpoint at Yq11 (interval 6) was mapped using Southern blotting and polymerase chain reaction (PCR). There were no nucleotide alterations in the SRY conserved domain. Histological analysis of the gonads showed an ovarian-like stroma with no signs of testicular tissue. These findings indicate that the patient was a mosaic 45,X/46,X,idic(Yp) whose phenotypic expression, including sex determination, appeared to have had more influence from the 45,X cell line.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/44. Del(X)(p21.1) in a mother and two daughters: genotype-phenotype correlation of Turner features.We report a mother and two daughters with partial Xp monosomy. Clinical assessment for Turner phenotype revealed that the three females manifested low-normal to mild short stature (-1.6 to approximately -2.3 SD) and variable degrees of skeletal features, such as cubitus valgus, short 4th matacarpals, and Madelung deformity, but no soft tissue or visceral anomalies or gonadal dysfunction. Cytogenetic studies for lymphocytes showed that the karyotype was 45,X[3]/46,X,del(X)(p21.1)[27] in the mother and non-mosaic 46,X,del(X)(p21.1) in the two daughters. fluorescence in situ hybridization and microsatellite analyses for 19 loci/regions on the x chromosome demonstrated that the del(Xp) chromosome was missing SHOX and had the breakpoint between DMD and CYBB. The results are consistent with the recently proposed notion that haploinsufficiency of SHOX results in not only short stature, but also Turner skeletal features in association with maturational effects of gonadal estrogens. The lack of soft tissue or visceral anomalies suggests the presence of the putative lymphogenic gene on the del(Xp) chromosome; the preservation of ovarian function appears to be compatible with meiotic pairing failure being relatively mild.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/44. Clinical, cytogenetic and molecular analysis of three 46,XX males.cytogenetic analysis, fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) were applied to characterize the Y-chromosomal breakpoints of three XX male patients. Two of these patients show a breakpoint within a protein kinase gene, PRKY, previously described as a hotspot of ectopic recombination between homologous regions on X and Y chromosomes during male meiosis. The slightly different clinical phenotypes of the three patients cannot be correlated with the localization of the breakpoints.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/44. A case of 45,X turner syndrome with spontaneous ovulation proven by ultrasonography.A well-documented case of non-mosaic turner syndrome, with spontaneous pubertal development and ovulatory cycles is reported. mosaicism could be excluded both by karyotyping of 172 metaphases of blood lymphocytes and fibroblasts, and by fluorescence in situ hybridization, using an X-centromeric probe, in 200 blood lymphocyte nuclei. This turner syndrome patient underwent normal pubertal development, with spontaneous menarche at 14 years, followed by regular monthly periods. Hormonal measurements performed during puberty were consistent with the patient's pubertal development. At the age of 26 years the patient was referred for complete fertility evaluation. Detailed hormonal analyses were performed in a given cycle. They showed midluteal phase estradiol and progesterone values within the range corresponding to normal ovulation and corpus luteum function. In the same cycle, pelvic ultrasonography was also performed at days 13, 15 and 18. It demonstrated a spontaneous ovulation, with follicular rupture that occurred between days 15 and 18. This is the first report of a spontaneous ovulation in turner syndrome evidenced, not only by hormonal analysis, but also by ultrasonographic demonstration of follicular rupture.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/44. Usefulness of fluorescence in situ hybridization for the diagnosis of Turner mosaic fetuses with small ring X chromosomes.OBJECTIVE: To emphasize the usefulness of fluorescence in situ hybridization (FISH) techniques on uncultured amniocytes for the diagnosis of abnormal mosaic karyotypes. methods: In the course of three prenatal diagnoses, specific fluorescent probes, coding, respectively, for chromosomes X, Y, 18, 13, and 21, were applied on amniocyte preparations directly after amniocentesis. At least 50 nuclei were counted in each case. Parallel to the FISH procedure, cell cultures were set up in order to obtain karyotypes. FISH and cytogenetic results were then compared. RESULTS: In each case, FISH showed an abnormal mosaic chromosomal constitution, 45,X/46,XX, which was related to the existence of tiny ring X chromosomes in karyotypes. CONCLUSION: Because very small ring X chromosomes can escape identification when standard cytogenetic techniques are used alone, we show that misdiagnosis can be avoided when FISH is performed beforehand.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
9/44. Different chromosome Y abnormalities in turner syndrome.A 17-year-old phenotypically female girl was referred for evaluation because of short stature and primary amenorrhea. cytogenetic analysis showed a mosaic 46,XY/45,X/47,XYY/46,X,idic(Yq)/47,XY,idic(Yq)/48,XXY,idic(Yq)/46,X,t(C;Y) karyotype. Conventional cytogenetic results were supplemented with fluorescence in situ hybridization (FISH) techniques to ensure a better characterization of abnormalities. By using FISH, a supernumerary marker chromosome derived from chromosome Y which could not be detected by conventional cytogenetics was revealed. Furthermore, additional abnormalities and their frequencies were highlighted by the application of dna probes specific for X and Y chromosomes. Thus, FISH proved useful in determining low frequency cell lines which would need analysis of a large number of good quality metaphase spreads by conventional cytogenetic techniques: it helped in identifying the nature and the origin of unknown markers and rearrangements which have important implication in sexual differentiation and development of gonadal tumours.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/44. prenatal diagnosis of 45,X and 45,X mosaicism: the need for thorough cytogenetic and clinical evaluations.OBJECTIVES: mosaicism involving a 45,X cell line is relatively common in prenatal diagnosis. In prenatally diagnosed cases, the prognosis of non-mosaic 45,X and 45,X/46,XY mosaicism are different. Therefore, accurate identification of a cell line containing y chromosome is critical for genetic counseling and postnatal management. methods: We investigated the ultrasound findings and outcomes of pregnancies with a 45,X cell line identified during mid-trimester cytogenetic analysis. RESULTS: A total of 105 cases were found to have a 45,X cell line by standard cytogenetic analysis. Seventy-four cases were found to have non-mosaic 45,X at initial diagnosis. Of these 74 cases, 68 had abnormal ultrasound findings that were characteristic of turner syndrome. Of the six cases with normal ultrasound findings, ultrasound examination was normal with male genitalia identified in three cases. Thorough cytogenetic and fluorescent in situ hybridization (FISH) analysis identified y chromosome material in all three cases, one with a dicentric Y;14 chromosome and the other two cases with a marker chromosome containing sex-determining Region (SRY) material in a small portion of the cells. In contrast, in 31 cases with a mosaic 45,X karyotype, ultrasound abnormality was identified only in one case. CONCLUSIONS: The present data suggest the need for follow-up ultrasound examination and thorough cytogenetic and molecular analysis for y chromosome material in 45,X cases with normal ultrasound findings.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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