1/8. Possible third case of Lin-Gettig syndrome.We report a patient with craniosynostosis, severe mental retardation, absence of the corpus callosum, camptodactyly, hypogonadism, and ventricular septal defect. We propose that he has Lin-Gettig syndrome and that he is the third reported patient with this entity. Our patient also had additional phenotypic features, including palatal cleft and absent rapid eye movement (REM) sleep that were not present in the two previously described patients with this syndrome. High-resolution karyotype and subtelomeric fluorescence in situ hybridization (FISH) for cryptic telomeric rearrangement were normal. The existence of an unrelated patient with Lin-Gettig syndrome supports that this is a separate and distinct clinical entity.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/8. Identification of a neocentromere in a rearranged y chromosome with no detectable DYZ3 centromeric sequence.An 18-year-old woman was evaluated because of primary amenorrhea and hypogonadism. Chromosome analysis from peripheral blood lymphocytes revealed a nonmosaic 46,X, mar constitution. The marker was shown to be a rearranged y chromosome consisting of an inverted duplication of the long arm: rea(Y)(qter-q11::q11-qter). Deletion mapping analysis with Y-specific STS showed that the marker lacked Yp and Y-centromeric (DYZ3) sequences, but it was positive for Yq sequences tested. fluorescence in situ hybridization analysis with Y and x chromosome centromeric and pancentromeric probes showed no hybridization signals. The marker chromosome is present in 100% of the cells; therefore, it is mitotically stable despite the absence of DYZ3 centromeric sequence. Hybridization with CENP-A and CENP-C specific antibodies localized a neocentromere close to the breakpoint.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
3/8. Ring chromosome 18q and jumping translocation 18p in an adult male with hypergonadotrophic hypogonadism.Constitutional jumping translocations (JT) are rare, especially in phenotypically normal individuals. We report on an adult male with partial hypogonadism as the sole phenotypic abnormality with an unusual chromosome abnormality. In this patient, centric fission of chromosome 18 lead to formation of a ring 18q chromosome, while 18p formed a JT through centromere-telomere fusion with chromosome 8q (66%) or 20q (13%). In 21% of cells, the 18p fragment was missing. Fluorescent in situ hybridization revealed the presence of interstitial telomeres at the junction site of the fusion and unequal distribution of the alphoid sequences through the centric fission, leaving a small, yet functional centromere within the ring. We discuss the phenotype of the patient in light of this unusual karyotype.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/8. dna hybridization study using Y-specific probes in an XX-male.A 30-year-old male attended the Toyama Medical and Pharmaceutical University Hospital with the chief complaint of infertility. physical examination showed bilateral small testes and the semen contained no sperm. Hormonal studies revealed hypergonadotropic hypogonadism and cytogenetic studies showed a 46,XX karyotype. High-resolution banding showed no abnormalities in both of the X chromosomes. Histological examination of both testes showed germinal aplasia and the proliferation of leydig cells. The diagnosis of XX-male was made from the above findings. A dna hybridization study using 17 Y-specific probes revealed the presence of a major part of the short arm of the y chromosome, which had presumably been translocated to the x chromosome. The translocated Y short arm had a small deletion within it.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
5/8. Deletion of specific sequences or modification of centromeric chromatin are responsible for y chromosome centromere inactivation.Stable dicentric chromosomes behave as monocentrics because one of the centromeres is inactive. The cause of centromere inactivation is unknown; changes in centromere chromatin conformation and loss of centromeric dna elements have been proposed as possible mechanisms. We studied the phenomenon of inactivation in two Y centromeres, having as a control genetically identical active Y centromeres. The two cases have the following karyotypes: 45, X/46,X,i(Y)(q12) and 46,XY/47,XY, t(X;Y) (p22.3;p11.3). The analysis of the behavior of the active and inactive y chromosome centromeres after Da-Dapi staining, CREST immunofluorescence, and in situ hybridization with centromeric probes leads us to conclude that, in the case of the isochromosome, a true deletion of centromeric chromatin is responsible for its stability, whereas in the second case, stability for its stability, whereas in the second case, stability of the dicentric (X;Y) is the result of centromere chromatin modification.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/8. Diagnosis of X-linked adrenal hypoplasia congenita by mutation analysis of the DAX1 gene.OBJECTIVE--To develop a rapid diagnostic approach to individuals with the X-linked cytomegalic form of adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH) due to mutations in DAX1, a new member of the nuclear hormone receptor gene superfamily. DESIGN--Molecular genetic diagnostic investigations of individuals with AHC and their relatives included polymerase chain reaction amplification of DAX1 for identification of intragenic mutations and fluorescence in situ hybridization with a cosmid containing the DAX1 gene for evaluation of larger deletions. PARTICIPANTS--Families that had males affected with AHC were evaluated for mutations involving the DAX1 gene. RESULTS--DAX1 mutations were identified in four families that had males affected with AHC. Two apparently independent pedigrees had an identical frame-shift mutation due to a single base pair deletion, and a third had a larger deletion involving the entire DAX1 locus. The fourth family was evaluated by fluorescence in situ hybridization for prenatal diagnosis, and both the DAX1 locus and the contiguous glycerol kinase region were deleted. CONCLUSIONS--Molecular genetic and molecular cytogenetic techniques represent rapid and complementary approaches to the diagnosis of mutations in the DAX1 gene responsible for AHC and the associated HH. Specific diagnosis of the cause of adrenal insufficiency in these boys permits anticipatory management of the HH and prenatal counseling for parents of the affected child and other members of their families.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
7/8. williams syndrome associated with chronic renal failure and various endocrinological abnormalities.A 31-year-old man who had been under regular hemodialysis for 6 months was diagnosed as williams syndrome (WS) by fluorescence in situ hybridization (FISH) chromosomal analysis. The association of WS and chronic renal failure (CRF) is only rarely encountered. Endocrinological examinations revealed hypergonadotropic hypogonadism. Prolonged and exaggerated responses of adrenocorticotropin (ACTH) to insulin-induced hypoglycemia and corticotropin releasing hormone (CRH) were also noted. While most of the endocrinological abnormalities observed in this patient could be attributed to altered endocrine circumstances in CRF, some findings stand in contrast. Furthermore, the testicular biopsy specimen showed severe hypospermatogenesis. Endocrine disorders observed in this patient may be at least in part, responsible for various clinical features underlying WS.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/8. Derivative y chromosome resulting from a t(Y;15) (q12;q11.2) in a boy with prader-willi syndrome.Chromosome analysis of peripheral lymphocytes from a boy with prader-willi syndrome showed the presence of 45 chromosomes, including der(Y) resulting from a t(Y;15) (q12;q11.2). in situ hybridization using DYZ3 and D15S11 showed a positive signal and negative signal in derivative y chromosome, respectively. The deficiency of 15pter q11.2 may not influence the clinical manifestation of prader-willi syndrome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |