Cases reported "Chromosome Fragility"

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1/164. Chromosome instability in lymphocytes from two patients affected by three sequential primary cancers: the role of fragile sites.

    The chromosomal aberration rate and the expression of fragile sites induced by aphidicolin were evaluated in metaphase chromosomes obtained from peripheral blood lymphocytes of two untreated patients with multiple primary cancers. Spontaneous aberrations of chromosome number and structure and chromosome fragility were compared with controls with the use of the same methods. Chromosomal aberration rates and expression frequencies of fragile sites were significantly higher in the patients than in normal control subjects. In the patients, all but one structural chromosome aberration involved at least one fragile site. Our results suggest that fragile sites may be unstable regions of the human genome, which might play an important role in the genetic instability associated with cancer predisposition. ( info)

2/164. Interstitial deletion of the long arm of chromosome 2: a clinically recognizable microdeletion syndrome?

    We report on a boy with an interstitial deletion of the long arm of chromosome 2 with breakpoints in chromosome bands q23 and q24.3. Main features were low-set and malformed ears, digital anomalies and congenital heart defects, which have also been reported in most of the previously described cases. A comparison of the features of the present patient with those in previously reported cases suggests the deletion 2q23q24 to be a clinically recognizable syndrome. ( info)

3/164. 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)

4/164. Bullous ichthyosiform erythroderma, developmental delay, aortic and pulmonary stenosis in association with a FRA12A.

    We present an 11-year-old female with bullous ichthyosiform erythroderma (BIE), learning disability, patent ductus arteriosus and mild stenosis of the aortic and pulmonary arteries. Chromosome analysis showed the expression of the rare folate-sensitive fragile site FRA12A at 12q13 in 8/20 (40%) of blood lymphocytes cultured in folate-deficient medium in the presence of trimethoprim. Her mother and maternal grandmother are phenotypically normal, but her mother shows expression of the same fragile site in 4/20 (20%) of cells cultured under the same conditions. lymphocytes from the grandmother only showed expression of the fragile site when cultured in the presence of methotrexate in folate deficient medium. Interestingly, two genes (keratin 1 and keratin 2e) which are known to cause BIE map to 12q13. Molecular data is presented excluding three candidate (CCG)n repeats within keratin 1 gene. We present a review of previously reported FRA12A cases and discuss possible molecular explanations for the clinical findings in this patient. ( info)

5/164. A case with 47,XXY,del(11)(q23) karotype-coexistence of Jacobsen and Klinefelter syndromes.

    A case with 47,XXY, del(11)(q23) karyotype-coexistence of Jacobsen and Klinefelter syndromes: A two-year-old dysmorphic male child was found to have 47,XXY,del(11)(q23) karyotype. Domination of the clinical features of Jacobsen syndrome was observed: mild mental retardation, trigonocephaly, ptosis, downward slanting palpebral fissures, low set ears, carp-shape mouth and micrognathia. Transient thrombocytopenia and leukopenia were also present. Over the following five years gynecomastia and eunuchoid body proportions became evident as clinical features of klinefelter syndrome. This is the first description of the coexistence of both syndromes. ( info)

6/164. Analysis of genomic instability using multiple assays in a patient with rothmund-thomson syndrome.

    We report on a patient with rothmund-thomson syndrome (RTS) whose cytogenetic evaluation showed a normal karyotype with no evidence of trisomy mosaicism or chromosomal rearrangements. Cultured lymphocytes from the patient, her mother, and a control exposed to mitomycin C and diepoxybutane did not show increased sensitivity to the dialkylating agents. Unlike some previous reports, we found no evidence of a deficiency in nucleotide excision repair, as measured with the functional unscheduled dna synthesis assay. glycophorin A analysis of red blood cells for somatic mutation revealed suspiciously high frequencies of both allele loss and loss-and-duplication variants in the blood of the patient, a pattern consistent with observations in other RecQ-related human diseases, and evidence for clonal expansion of a mutant clone in the mother. Discrepant results in the literature may reflect true heterogeneity in the disease or the fact that a consistent set of tests has not been applied to RTS patients. ( info)

7/164. Mental retardation with rare fragile site expressed at 2q11.

    Several rare autosomal folate sensitive fragile sites were reported in individuals with mental retardation, neurological abnormalities, and multiple congenital malformations. Only three of them: fra(11)(q22.3), fra(X)(q27.3) and fra(X)(q28), are known to be associated with mental retardation and phenotypic abnormalities. A possible association of the other rare fragile sites with idiopathic mental retardation is still being discussed. Here, a girl who has a fragile site at 2q11 with minor congenital anomalies and mental retardation is presented. This case has recalled the question of idiopathic mental retardation that might be the clinical expression of rare FSFS. Fragility was observed at 2q11 with a frequency of 3% in her cells along with a partial endoreduplication at 2 q11-->qter. ( info)

8/164. Molecular and clinical characterization of a patient with a chromosome 4p deletion, wolf-hirschhorn syndrome, and congenital glaucoma.

    wolf-hirschhorn syndrome is a developmental disorder associated with hemizygous deletion of the distal short arm of chromosome 4. We have identified a patient affected with wolf-hirschhorn syndrome and early onset glaucoma. Five other patients with wolf-hirschhorn syndrome and early onset glaucoma or ocular anomalies associated with early onset glaucoma have been previously described, suggesting that the association with wolf-hirschhorn syndrome is not coincidental. The infrequent association of early onset glaucoma suggests that the chromosomal region commonly deleted in Wolf-Hirschhorn patients does not contain genes responsible for early onset glaucoma. In this study, we performed a molecular characterization of the deleted chromosome 4 to determine the extent of the deletion in an attempt to begin to identify the chromosomal region responsible for the associated glaucoma. Using microsatellite repeat markers located on 4p, we determined that the deletion spanned a 60-cM region including the minimal Wolf-Hirschhorn region. The proximal breakpoint occurred between markers D4S3045 and D4S2974. These results support the hypothesis that patients with wolf-hirschhorn syndrome and early onset glaucoma may have large deletions of 4p that include a gene(s) that may be responsible for a dominant form of congenital glaucoma. ( info)

9/164. Rearrangement in the coding region of the MYCN gene in a subset of amplicons in a case of neuroblastoma with MYCN amplification.

    The MYCN gene is often amplified but rarely rearranged in neuroblastoma. We report, for the first time, a rearrangement within the MYCN coding region in a metastatic neuroblastoma in a 3-year-old boy with MYCN amplification in his primary tumor. The rearrangement occurred 46 nucleotides downstream from the ATG codon in exon 2 of MYCN. The amplification level of the rearranged copies of the MYCN gene was lower than that of the unrearranged copies of MYCN. These results indicate that the rearrangement occurred after initial MYCN gene amplification. Monochromosomal somatic cell hybrid mapping of the novel region fused to exon 2 of MYCN localized it to chromosome 2, suggesting that this rearrangement resulted from an interstitial deletion, presumably within the MYCN amplicon itself. ( info)

10/164. Acral myxoinflammatory fibroblastic sarcoma with unique clonal chromosomal changes.

    Acral myxoinflammatory fibroblastic sarcoma is a rare tumor of the distal extremities. We present the hitherto unreported karyotypic abnormalities of this new entity. The tumor presented as a mass in the dorsum of the foot in a 53-year-old woman and showed the typical virocyte-like and lipoblast-like cells in a myxoid and inflammatory background. cytogenetic analysis revealed a complex karyotype with a reciprocal translocation t(1;10) (p22;q24) in addition to the loss of chromosomes 3 and 13. fluorescence in situ hybridization with the 769E11YAC and BAC 31L5 and 2H23 probes showed the breakpoint to be located proximally to BCL10 and distally to GOT1 genes on chromosomes 1p22 and 10q24, respectively. The presence of these clonal chromosomal changes supports the neoplastic nature of acral myxoinflammatory fibroblastic sarcoma and underscores that it represents a separate entity. ( info)
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