11/128. A malignant triton tumor with an unbalanced translocation (1;13)(q10;q10) and an isochromosome (8)(q10) as the sole karyotypic abnormalities. The karyotype of a malignant nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor) of a 58-year-old woman is reported. The tumor revealed an isochromosome for the long arm of chromosome 8 and an unbalanced translocation (1;13)(q10;q10) leading to a gain of the long arm of chromosome 1 as the sole karyotypic abnormalities. ( info) |
12/128. 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. ( info) |
13/128. Isodicentric y chromosome in an Ullrich-Turner patient without virilization. We report on a 17-year-old young woman with Ullrich-turner syndrome (UTS), who was found to have a karyotype 45,X/46,X,idic(Y)(q11). She had age-appropriate genitalia without virilization in spite of the presence of the Y-derived marker chromosome and SRY locus in 70% of her lymphocytes. Having reviewed the literature, we conclude that a possible explanation for the lack of virilization in these mosaic patients is most likely an uneven distribution of tissue mosaicism (gonadal mosaicism). ( info) |
14/128. blast crisis of Ph-positive chronic myeloid leukemia with isochromosome 17q: report of 12 cases and review of the literature. Isochromosome 17q [i(17q)] is frequently observed in the blast crisis (BC) of chronic myelogenous leukemia (CML). It has been suggested that this chromosome abnormality is associated with special hematological characteristics of the BC, but the information on this subject is scarce. The clinical, hematological and cytogenetic features of patients with i(17q) were analyzed in a series of 121 patients with BC of Ph-positive CML. Twelve patients (10%) displayed an i(17q), representing the third commonest cytogenetic abnormality, after trisomy 8 and Ph chromosome duplication. In seven of the 12 patients the BC was preceded by an accelerated phase, and 10 had more than 10% blood basophils at BC diagnosis. The blast cells had a myeloid phenotype in the 12 patients. Five patients exhibited cytogenetic abnormalities in addition to i(17q), with trisomy 8 and duplication of the Ph chromosome being the alterations most frequently observed. Median survival of patients with i(17q) was 22 weeks, which was not significantly different from the survival of patients with myeloid BC in the overall series. These results are similar to the findings in 181 patients with i(17q) from 12 series of the literature, and confirm the special hematologic profile of BC of CML with this cytogenetic abnormality. ( info) |
15/128. 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. ( info) |
16/128. 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. ( info) |
17/128. Three probands with autistic disorder and isodicentric chromosome 15. We have identified three unrelated probands with autistic disorder (AD) and isodicentric chromosomes that encompass the proximal region of 15q11.2. All three probands met the diagnostic and statistical manual of mental disorders, fourth edition [DSM-IV; American Psychiatric association, 1994], and international classification of diseases ( ICD-10) diagnostic criteria for AD, confirmed with the Autism Diagnostic interview -Revised (ADI-R). Chromosome analysis revealed the following karyotypes: 47,XX, idic(15)(q11.2), 47,XX, idic(15) (q11.2), and 47,XY, idic(15)(q11.2). Haplotype analysis of genotypic maker data in the probands and their parents showed that marker chromosomes in all three instances were of maternal origin. Comparison of the clinical findings of the three AD probands with case reports in the published literature (N = 20) reveals a clustering of physical and developmental features. Specifically, these three probands and the majority of reported probands in the literature exhibited hypotonia (n = 13), seizures (n = 13), and delayed gross motor development (n = 13). In addition, clustering of the following clinical signs was seen with respect to exhibited speech delay (n = 13), lack of social reciprocity (n = 11), and stereotyped behaviors (n = 12). Collectively, these data provide further evidence for the involvement of chromosome 15 in AD as well as present preliminary data suggesting a clustering of clinical features in AD probands with proximal 15q anomalies. ( info) |
18/128. Pallister-Killian syndrome presenting through nuchal translucency screening for trisomy 21. Pallister-Killian syndrome (tetrasomy 12p) is an uncommon aneuploidy, which may present in the prenatal period with an ultrasonographically detected fetal abnormality or following karyotyping for maternal age. We report a case that presented with increased nuchal translucency and hydrops at a first trimester screening scan for trisomy 21. ( info) |
| 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. ( info) |
20/128. Isochromosome (7)(q10) in Shwachman syndrome without MDS/AML and role of chromosome 7 anomalies in myeloproliferative disorders. Shwachman syndrome (SS) is an autosomal recessive disorder in which bone marrow dysfunction is observed, with development of myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML) in up to one third of the cases. Inconclusive data are available as to increased chromosome breakage in SS, while chromosome 7 anomalies, and often an isochromosome (7)(q10), are frequent in cases with MDS/AML. We report on the consistent presence of an i(7)(q10) in the bone marrow and blood lymphocytes in one of two sisters affected with SS without any clinical or cytological signs of MDS/AML. Thus, this patient was either a case of constitutional mosaicism for the i(7)(q10), or this had to be acquired in a nondysplastic and non-neoplastic marrow clone. dna polymorphism analysis demonstrated the paternal origin of the i(7q). We postulate that the SS mutation acts as a mutator gene, and causes karyotype instability; abnormal clones would thus arise in the marrow, and chromosome 7 anomalies, i(7q) in particular, will in turn lead to MDS/AML. If this interpretation is correct, it would be also an indication to consider chromosome 7 anomalies in general, out of SS, as primary changes in MDS/AML pathogenesis. ( info) |