1/10. Localization of SRY by primed in situ labeling in XX and XY sex reversal.primed in situ labeling (PRINS) can be used to localize dna segments too small to be detected by fluorescence in situ hybridization. By PRINS we identified the SRY gene in two XX males, a woman with XY gonadal dysgenesis, and an azoospermic male with Xp-Yp interchange. Because PRINS has been used generally in the study of repetitive sequences, we modified the technique for study of the single copy 2. 1-kb SRY sequence. SRY signals were identified at band Yp11.31p11.32 in normal XY males and in the woman with XY gonadal dysgenesis. SRY signals were identified on Xp22 in one XX male but not in the other. They were identified in the corresponding region (Xp22) of the der(X) in the azoospermic male with Xp-Yp interchange. SRY signals were not observed in normal XX females. Presence of SRY in dna samples from the various subjects was confirmed by polymerase chain reaction. We conclude that PRINS is ideal for rapid localization of single copy genes and small dna segments in general.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/10. Familial ovarian dysgerminomas (Swyer syndrome) in females associated with 46 XY-karyotype.An asymptomatic woman (age 38 years) with a family history of ovarian malignancies was referred for presymptomatic genetic testing of mutations in the BRCA genes. A familial Swyer syndrome with the occurrence of dysgerminomas is the most likely diagnosis. However, in our case, all known causes of this heterogeneous disorder have been excluded pointing to the existence of another yet unknown genetic locus. The family history revealed three affected paternal aunts. Two of them developed ovarian malignancies at 13 and 15 years of age, and died at ages 19 and 20. The third aunt, 82 years old, was affected by this disease at the age of 35. She underwent hormonal treatment for 3 years starting at the age of 15 because of primary amenorrhea. Under this treatment she developed nearly complete secondary sexual characteristics. karyotype analysis revealed a normal male karyotype (46 XY, QFQ). Pelvic ultrasound showed an uterus of normal size, incompatible with an androgen resistance syndrome or a defect in testosterone biosynthesis. We excluded a mutation in the sex-determining region on chromosome Y (SRY) by direct sequencing of the SRY gene. An involvement of the subtelomeric region of chromosome 9p (9p 24.3) recently reported to be involved in XY-sex reversal phenotypes was excluded by molecular testing for loss of heterozygosity as well as fluorescence in situ hybridization studies. Analyses of the DAX1 gene in the dosage sensitive sex reversal locus on chromosome Xp21 by Southern blot analysis showed no duplications.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/10. microcephaly, jejunal atresia, aberrant right bronchus, ocular anomalies, and XY sex reversal.We present a patient with microcephaly, jejunal atresia, aberrant right tracheobronchial tree, mild left blepharoptosis, and corectopia (irregular pupil), left sectoral iris stromal hypoplasia and peripheral anterior synechia, and 46,XY sex reversal. Testosterone and dihydrotestosterone (DHT) levels were within normal limits for a male infant at 3 weeks of age. Gonadectomy at age 18 months revealed immature testis tissue and no evidence of Mullerian structures. PCR amplification of the androgen receptor (AR) gene and flanking genomic regions revealed no evidence for deletion. Array-comparative genomic hybridization (array-CGH) for assessment of gene dosage in other regions of the genome was normal. This patient represents a multiple anomaly disorder similar to intestinal atresia-ocular anomalies-microcephaly syndrome (MIM#243605) but incorporating 46,XY sex reversal with testicular tissue, demonstrating a defect in the sexual differentiation pathway.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/10. Analysis of SRY gene in 8 cases of sex abnormality.In order to investigate the relationship between sex dysplasia and sex-determining region Y (SRY) gene, 8 patients with sexual abnormality were analyzed by cytogenetic and molecular genetic methods. fluorescence in situ hybridization (FISH) using PY3.4, X alpha satellite, and SRY probes was performed in each case to analyze the sex chromosome translocation and gene translocation. SRY gene was amplified by polymerase chain reaction (PCR) and its mutation was detected by direct sequencing. The results showed that among 8 patients, 5 were positive for SRY and the remaining negative for SRY. In the patients positive for SRY genes, 3 presented testes and the left 2 streak ovaries. In the patients negative for SRY, only one case presented testes, while 2 ovaries. Direct sequencing demonstrated that all SRY genes were normal in the patients positive for SRY genes. FISH technique demonstrated that SRY genes translocated from Ypter to Xpter in 2 46,XX phenotypic males positive for SRY genes. It was concluded that SRY gene is strongly involved in male sex determination, while a sequence of other genes may be taken into account in sexual development.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/10. Swyer syndrome with SRY y chromosome and rudimentary internal genitalia demonstrating temporary action of antimullerian hormone in utero: a case report.BACKGROUND: XY gonadal dysgenesis is characterized by streak gonads in phenotypic females without somatic abnormalities. This case demonstrated a hypoplastic uterus, an unlikely finding for the syndrome, suggesting insufficient function of antimullerian hormone prenatally. CASE: A 20-year-old, female virgin was first seen 2 years earlier complaining of primary amenorrhea. She was 168 cm tall, and secondary sexual characteristics, such as breast development and pubic and axillary hair, were absent on physical examination. Chromosome analysis with fluorescence in situ hybridization revealed 46,XY, and a molecular investigation was undertaken to assess the possibility of a mutation in SRY through dna sequencing. SRY mutations were absent. Bilateral laparoscopic removal of dysgenetic gonads was performed at another medical center immediately after genetic confirmation for an increased risk of malignancy. When the patient was seen 1 year later, we performed ultrasonography because of no menstrual outflow. Pelvic ultrasonography revealed a hypoplastic uterus (26 x 12 mm) with a rudimentary cervix. CONCLUSION: Clinical phenotypes of different mutations of the y chromosome, particularly on SRY, may cause Swyer syndrome patients to have a uterus with fertility potential after oocyte donation.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/10. in situ hybridization analysis of the y chromosome in gonadoblastoma.gonadoblastoma is a rare tumor arising in the streak gonads of about 30% of 46,XY sex-reversed females. Because gonadoblastoma develops only in patients who have Y-chromosome material and dysgenetic gonads, it has been hypothesized that positive expression of a gene (or genes) on the y chromosome (GBY) is involved in the etiology of the tumor. To examine the y chromosome directly in tumors, we performed nonisotopic in situ hybridization of a biotin-labeled Y-specific probe for the DYZI locus on formalin-fixed, paraffin-embedded sections of tumor samples from four different patients. After hybridization to DYZI, the y chromosome was found to be present in all gonadoblastoma foci in the four patients studied, and the gonadoblastoma foci showed an average of 85% cell nuclei positive for the y chromosome on tissue sections. Normal male and female control tissues showed an average of 78% and 0% positive nuclei, respectively. One patient with bilateral gonadoblastoma had previously been shown to be mosaic, with a 45,X/46,XY karyotype in lymphocytes, skin fibroblasts, and cultures from both gonads. Examination of sections of this patient's gonads showed 79% positive nuclei within the gonadoblastoma foci, whereas the nontumor stromal tissue had 19% positive nuclei. These results indicate that, in this mosaic gonad, tumor foci developed only from cells that had a y chromosome. Our results support the hypothesis that there is a GBY locus on the y chromosome and that the y chromosome is retained in the gonadoblastoma foci during the development of the tumor.- - - - - - - - - - ranking = 6keywords = hybridization (Clic here for more details about this article) |
7/10. Gonadal agenesis in XX and XY sisters: evidence for the involvement of an autosomal gene.Two agonadic sisters, one with a 46,XY and the other with a 46,XX karyotype, both with normal female external genitalia and hypoplastic Mullerian derivatives, born to a consanguineous marriage, were studied from a clinical, endocrinological, histological, and genetic perspective. Using PCR amplification, Southern hybridization, and DGGE analysis, it was found that the XY patient had no mutations in the conserved sequence of the SRY gene, the putative testis-determining gene in mammals, whereas her XX affected sister is SRY-negative. To our knowledge, this is the first report of XY and XX sibs in familial gonadal agenesis without other somatic abnormalities. The involvement of an autosomal locus impeding gonadal development in both sexes is discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/10. Characterization by fluorescence and electron microscopy in situ hybridization of a double Y isochromosome.A patient with mixed gonadal dysgenesis and Y isochromosomes i(Y) is described. Lymphocyte cultures from peripheral blood contained a high proportion of 45,X cells and several other cell lines with two different marker chromosomes (mars). These markers had either a monocentric (mar1) or a dicentric appearance (mar2). Following high-resolution GTG, RBG, QFQ, and CBG bandings, five cell lines were identified; 45,X/46,X, mar1/46,X, mar2/47,X, mar1x2/47,X, mar2x 2. The percentages were 66/6/26/1/1%, respectively. chromosome banding analyses were insufficient for characterization of the markers. in situ hybridization of specific probes for the Y centromere and its short arm showed, both in fluorescence and electron microscopy (EM), two different Y rearrangements. Mar1 is an isochromosome for the short arm i(Yp) and mar2 is a dicentric which was shown by EM to be a double isochromosome Yp, inv dup i(Yp). The breakpoint producing mar1 is within the centromere and the one producing mar2 is within one of the short arms of the Y isochromosome. The findings of different cell populations in peripheral blood lymphocytes indicate the postzygotic instability of this i(Yp).- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
9/10. Gonadoblastomas in 45,X/46,XY mosaicism: analysis of y chromosome distribution by fluorescence in situ hybridization.Gonadoblastomas are composed of nests of neoplastic germ cells and sex cord derivatives surrounded by ovarian-type stroma. These tumors are found almost exclusively in persons with gonadal dysgenesis associated with a y chromosome or y chromosome fragment, and accordingly, the y chromosome has been implicated in gonadoblastoma oncogenesis. To evaluate this association, we used two-color fluorescence in situ hybridization with chromosome-specific probes to determine the distribution of the X and Y chromosomes in the tumor nests and surrounding stromal cells in paraffin tissue sections of three gonadoblastomas in two patients with gonadal dysgenesis and 45,X/46,XY mosaicism. Statistical analysis of the data from the fluorescence in situ hybridization demonstrated that in all three gonadoblastomas, the proportion of nuclei with a y chromosome signal was significantly higher in the tumor cells than in the nontumoral cells of the surrounding stroma (P<.001). These results suggest that y chromosome material participates in gonadoblastoma tumorigenesis.- - - - - - - - - - ranking = 6keywords = hybridization (Clic here for more details about this article) |
10/10. RB1 deletion in gonadoblastoma in an XY female.Cytogenetic studies of normal and tumor cells in a patient with gonadal dysgenesis and bilateral gonadoblastoma were performed. The karyotype was 46,XY in peripheral blood lymphocytes and skin fibroblasts. The conserved region of the SRY gene was detected by polymerase chain reaction amplification. Sequencing of this region did not reveal any alterations. A 46,XY chromosome constitution was observed in the right gonadoblastoma, but a partial deletion of chromosome 13 was present in the left tumor. This deletion included band 13q14, where the retinoblastoma gene is mapped. The study of the polymorphism of the variable number of tandem repeats region in intron 17 of the RB1 locus disclosed loss of heterozygosity in both the left tumor, which showed the deletion of chromosome 13, and in the right tumor, where no chromosome alterations of chromosome 13 were detected. in situ hybridization covering 130 kb of RB1 showed that a partial deletion of one of the RB1 alleles had occurred in the right tumor. Since the deletions affected different alleles in each tumor, independent events must have been involved in the development of the tumors. These findings point toward a significant role of RB1 in the development of gonadoblastoma.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
| | Next -> |