1/42. Uniparental isodisomy resulting from 46,XX,i(1p),i(1q) in a woman with short stature, ptosis, micro/retrognathia, myopathy, deafness, and sterility.We report on a 43-year-old woman who was referred for evaluation because of minor facial anomalies, myopathy, sterility, short stature, hearing loss, downward slant of palpebral fissures, bilateral ptosis, severe micro/retrognathia, high arched palate, and scoliosis. Cytogenetic analyses utilizing GTG/CBG bandings showed presence of one i(1p) and one i(1q) without normal chromosome 1 homologues. fluorescence in situ hybridization analysis showed hybridization to only two chromosomes, consistent with the G-banded interpretation of i(1p) and i(1q). To the best of our knowledge, this is the first case of isochromosomes 1p and 1q replacing the two normal chromosome 1s. Molecular investigations using markers for chromosome 1 showed inheritance of only one set of paternal alleles and absence of any maternal alleles in the patient. The adverse phenotype of the patient may be due to one or more recessive mutations, genomic imprinting, or a combination of both.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/42. Formation of supernumerary euchromatic short arm isochromosomes: parent and cell stage of origin in new cases and review of the literature.In order to get insight in the formation of isochromosomes we analysed different supernumerary euchromatic short arm isochromosomes for the parent and cell stage of origin. After cytogenetic detection and confirmation by fluorescence-in-situ hybridization we performed short tandem repeat typing in a child with i(9p), three with i(12p) and three with i(18p). The extra chromosomes were monocentric in each case, the i(9p) and i(12p) constitutions were found in mosaic with normal cell lines. Our results and those of other groups indicate a strong role of maternal meiosis in isochromosome formation: in one i(8p), 4 out of 5 i(9p), 7 out of 12 i(12p) and 18 out of 23 i(18p) families a maternal meiotic nondisjunction had occurred prior to the centromere misdivision. For chromosome 18, the majority of isochromosomes originated from a maternal meiosis II error (16/18). For the other tetrasomic constitutions the isochromosomes could be delineated from paternal as well as from maternal origin, the short tandem repeat typing patterns being consistent with meiotic or mitotic cell stages of formation. Thus, independently of the chromosomal origin, in the majority of cases with additional euchromatic isochromosomes maternal meiosis nondisjunction is the initial step followed by centromeric misdivision. Postzygotic nondisjunction as suggested previously due to mosaics observed in tetrasomies 9p and 12p seems to be of minor importance. The observed origin of isochromosomes 18 corresponds to that of trisomy 18, where the majority of cases can be delineated from maternal meiosis II errors.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
3/42. Consistency of isochromosome 7q and trisomy 8 in hepatosplenic gammadelta T-cell lymphoma: detection by fluorescence in situ hybridization of a splenic touch-preparation from a pediatric patient.Hepatosplenic gamma-delta (gammadelta) T-cell lymphoma is a rare but increasingly recognized lymphoid malignancy predominantly affecting young adult males. It is not well appreciated in the pediatric population. We report the third case of this aggressive lymphoma in a child as well as additional support for the consistency of the recently discovered cytogenetic abnormalities, isochromosome 7q and trisomy 8, which in this case were documented using fluorescence in situ hybridization (FISH) of a touch-preparation of the spleen.- - - - - - - - - - ranking = 2.5keywords = hybridization (Clic here for more details about this article) |
4/42. Prenatal detection of trisomy 18 caused by isochromosome 18p and 18q formation.We report on the prenatal detection and further genetic studies in a case of trisomy 18 caused by isochromosome 18p [i(18p)] and 18q [i(18q)] formation. The diagnosis was made by standard cytogenetic techniques in amniotic fluid cells and confirmed by fluorescence in situ hybridization. The formation of the isochromosomes cannot be explained by a single model; centromere misdivision and meiosis II nondisjunction without recombination or mitotic misdivision are the most likely mechanisms of formation as indicated by dna analysis.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
5/42. 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 = 0.5keywords = hybridization (Clic here for more details about this article) |
6/42. An isochromosome 6p in a primary meningeal malignant melanoma.The rearrangement of chromosome 6, particularly the deletion of 6q, has been observed in human malignant melanoma with or without brain metastases. The isochromosome 6p has also been described. In this study, we report the cytogenetic analysis of a primary malignant melanoma of the central nervous system. Its dominating karyotype was 47,XX, i(6)(p10). fluorescence in situ hybridization (FISH), using a 6p chromosome arm probe, confirmed the structure of the isochromosome. To our knowledge, this is the first report of this type of chromosomal aberration in an uncommon neoplasm of leptomeningeal melanocytic origin.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
7/42. Hepatosplenic alphabeta T-cell lymphoma: an unusual case with clinical, histologic, and cytogenetic features of gammadelta hepatosplenic T-cell lymphoma.Hepatosplenic gammadelta T-cell lymphoma is a recently identified entity in which lymphoma cells bearing the gammadelta T-cell receptor (TCR) infiltrate the sinusoids of the liver and the sinuses of the splenic red pulp and bone marrow, without lymph node involvement. It is also characterized by a recurrent cytogenetic finding, isochromosome 7q (i7q10). The authors report a case of hepatosplenic lymphoma of alphabeta T-cell phenotype that shares the same clinical, histologic, and cytogenetic characteristics of the previously described hepatosplenic gammadelta T-cell lymphoma. Fluorescent in situ hybridization performed with chromosome 7 probes showed the typical pattern of isochromosome 7q. Genomic analysis of the TCR gamma locus failed to detect a clonal rearrangement. This unique case of hepatosplenic lymphoma of alphabeta T-cell phenotype supports the possibility that lymphoid populations of different alphabeta or gammadelta phenotype that share similar homing and presumably functional properties could give rise to lymphomas displaying similar clinical and pathologic findings.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
8/42. 4p- syndrome and 9p tetrasomy mosaicism with cleft lip and palate.Chromosome 4p- syndrome is a multiple malformation syndrome associated with partial deletion of the short arm of chromosome 4 (4p-). It is characterized by dysmorphic features and retarded development. cleft lip and/or palate are the major clinical manifestations. Cases of tetrasomy 9p are extremely rare; the principal clinical manifestations of this condition are characteristic craniofacial abnormalities, generalized hypotonia and severe mental retardation. We present the first case of a female infant with 4p deletion and tetrasomy 9p mosaicism, exhibiting a left-sided cleft lip, alveolus and soft palate. karyotype analysis of lymphocytes cultured from the patient revealed that she was mosaic: 86% of the cells were 46, XX, add (4) (p15.32) and 14% were 47, XX, add (4) (p15.32), idic (9)(q12). The G-banding pattern appeared consistent with either translocation or partial proximal deletion of 4p. In order to make a definitive cytogenetic diagnosis of isodicentric chromosome 9, fluorescence in situ hybridization (FISH) was applied. At 8 months, when the patient weighed 4.3 kg, her cleft lip was repaired. Before and after surgery there were no seizures, and the postoperative course was uneventful.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
9/42. Fusion of 9 beta-satellite and telomere (TTAGGG)n sequences results in a jumping translocation.A newborn was found to have an isochromosome for the short arm of chromosome 9, i(9p) and a jumping translocation of the whole long arm. In 94.4% metaphases, 9q was fused to the telomere of chromosome 19p and, in 5.6% of metaphases, 9q was fused to the telomere of chromosome 8p. The net result was trisomy for the short arm of chromosome 9. With the pan telomere probe, fluorescent in situ hybridization (FISH) investigations found an interstitial telomere on the der(19) and der(8). The 9 beta and classical satellite probes gave a signal only on the long arm of chromosome 9 involved in the jumping translocation. The 9 alpha satellite probe hybridized to i(9p) and not to the other derivative chromosomes. A combination of chromosome 9 (red) and chromosome 19 (green) paint probes used to rapidly screen metaphases for the jumping translocation found 88 metaphases had a der(19)t(9;19) and 4metaphases had a der(8)t(8;9). For the first time, the junction of a jumping translocation has been shown to involve the telomere sequence (TTAGGG)n and beta-satellite sequences by FISH. In this paper, we also review the simultaneous occurrence of an isochromosome for the short arm and translocation of the whole long arm and constitutional jumping translocations.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
10/42. Isodicentric 7p, idic(7)(q11.2), in acute myeloid leukemia associated with older age and favorable response to induction chemotherapy: a new clinical entity?Three adult de novo acute myeloid leukemias (AML M1, M2, and M4) with an isochromosome 7p are presented. No additional abnormalities were detected by G-band and multicolor, using combined binary ratio labeling, fluorescence in situ hybridization (FISH) analyses, indicating that the i(7p) was the sole, i.e., the primary, chromosomal aberration. Although the patients were elderly--68, 72, and 78 years old--they all responded very well to chemotherapy, achieving complete remission lasting more than a year. Further FISH analyses, using painting, centromeric, as well as 7q11.2-specific YAC probes, revealed that the i(7p) contained two centromeres and that the breakpoints were located in 7q11.2. Thus, the abnormality should formally be designated idic(7)(q11.2). The detailed mapping disclosed a breakpoint heterogeneity, with the breaks in 7q11.2 varying among the cases, being at least 1,310 kb apart. Furthermore, the breakpoints also differed within one of the cases, being located on both the proximal and the distal side of the most centromeric probe used. Based on our three patients, as well as on a previously reported 82-year-old patient with AML M2 and idic(7)(q11) as the only chromosomal change, we suggest that this abnormality, as the sole anomaly, is associated with AML in elderly patients who display a good response to induction chemotherapy and, hence, have a favorable prognosis. Furthermore, the heterogeneous breakpoints in 7q11.2 suggest that the important functional outcome of the idic(7)(q11.2) is the genomic imbalance incurred, i.e., gain of 7p and loss of 7q material, rather than a rearrangement of a specific gene.- - - - - - - - - - ranking = 0.5keywords = hybridization (Clic here for more details about this article) |
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