1/4. Ring chromosome 22 and neurofibromatosis.Variable constitutional mosaicism, mos45,XY,-22/46,XY,-22, mar/46,XY,-22, r(22)/47,XY,-22, r(22) mar/ 47, XY,-22, r(22)*2, was found in PHA-stimulated peripheral blood, in a lymphoblastoid cell line and in cultured skin fibroblasts from a mentally retarded patient with neurofibromatosis. Both the ring chromosome and the small extra marker chromosome stained positively by in situ hybridization with a chromosome 14/22-specific alphoid repeat probe. DNA dosage analysis showed constitutional loss of one copy of the arylsulfatase A gene (ARSA), consistent with its terminal location on 22q. There was no evidence of constitutional loss of D22S1 or D22S28 which flank the neurofibromatosis type 2 (NF2) locus. Analysis of two DNA samples from a skin neurofibroma indicated retainment of two copies of D22S1, whereas the results were ambiguous with respect to tumor-specific loss of one copy of D22S28. It is suggested that the development of neurofibromatosis of unclear type in two r(22) carriers might be associated with somatic mutation of the NF2 locus due to instability of the ring chromosome(s), and in analogy, that somatic mutation of either NF1 or NF2 may account for some cases of neurofibromatosis which do not meet the criteria of either NF1 or NF2. The occurrence of seminoma in the proband may be fortuitous, but could also be due to the presence of a seminoma-associated locus on chromosome 22.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/4. dysgerminoma of the ovary in a patient with triple-X syndrome.A 24-year-old patient with dysgerminoma of the right ovary and hypoplastic left ovary was screened for chromosomal aberration. Triple-X syndrome was found in the oral epithelium and lymphocyte culture, while chromosomal in situ hybridization of the tumor itself showed a normal XX karyotype. Although trisomy X and dysgerminoma are coincidental findings in our case report, women with malignant germ cell tumors and abnormal genitalia should be checked for chromosomal aberrations to exclude anomalies carrying a y chromosome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/4. dysgerminoma and gonadal dysgenesis in a 46,XX female with no evidence of Y chromosomal DNA.The occurrence of dysgerminoma in dysgenetic gonads without Y chromosomal influence is exceptionally rare. We used Southern blot hybridization of Y-dna probes to genomic DNA to search for any Y-related influence in a patient with a dysgerminoma, dysgenetic gonads, and a 46,XX karyotype. No Y-specific DNA was found at 11 loci representing the short arm, centromere, and long arm. This absence of any Y-DNA leaves open to question the absolute requirement of Y-related influence in the development of dysgerminoma in dysgenetic gonads.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/4. Unique combination of an ovarian gonadoblastoma, dysgerminoma, and mucinous cystadenoma in a patient with Turner's syndrome: a cytogenetic and molecular analysis.Phenotypically female patients with a (mosaic) XY karyotype are at high risk to develop gonadoblastoma with potential progression to dysgerminoma. We studied a Turner's syndrome patient with a composite ovarian neoplasm of a gonadoblastoma, a dysgerminoma, and a mucinous cystadenoma. Nonradioactive in situ hybridization showed that the patient had a XO/XY genotype with deletion of part of Yq. Molecular analysis located the chromosomal breakpoint in deletion interval 6, indicating that potential genes responsible for the development of gonadoblastoma may be located on the short arm of the y chromosome or on the long arm, centromeric of deletion interval 6. Moreover, using the XO/XY mosaicism as a clonal marker, the dysgerminoma and the mucinous cystadenoma were shown to be of independent origin. Therefore, in this case, we find support for the hypothesis that mucinous cysts with gastrointestinal epithelium can be of ovarian surface epithelial cell origin. This case also demonstrated that the occurrence of a composite tumor does not unequivocally imply that both components are of the same origin. Clonal analysis is required to determine the relation of the tumor constituents.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |