1/6. Myelodysplastic syndrome associated with monosomy 7 in a child with bloom syndrome.bloom syndrome is a genomic instability syndrome associated with predisposition to development of various types of malignancy. In this report, we described a 7-year-old boy with bloom syndrome (BS) and myelodysplastic syndrome (MDS) associated with monosomy 7 and loss of the y chromosome. To our knowledge, this was the first case with BS showing monosomy 7 and MDS during the early childhood period.- - - - - - - - - - ranking = 1keywords = genomic instability, instability, genomic (Clic here for more details about this article) |
2/6. Nuclear structure in normal and bloom syndrome cells.bloom syndrome (BS) is a rare cancer-predisposing disorder in which the cells of affected persons have a high frequency of somatic mutation and genomic instability. BLM, the protein altered in BS, is a RecQ DNA helicase. This report shows that BLM is found in the nucleus of normal human cells in the nuclear domain 10 or promyelocytic leukemia nuclear bodies. These structures are punctate depots of proteins disrupted upon viral infection and in certain human malignancies. BLM is found primarily in nuclear domain 10 except during s phase when it colocalizes with the werner syndrome gene product, WRN, in the nucleolus. BLM colocalizes with a select subset of telomeres in normal cells and with large telomeric clusters seen in simian virus 40-transformed normal fibroblasts. During s phase, BS cells expel micronuclei containing sites of DNA synthesis. BLM is likely to be part of a DNA surveillance mechanism operating during s phase.- - - - - - - - - - ranking = 1keywords = genomic instability, instability, genomic (Clic here for more details about this article) |
3/6. Numerous colonic adenomas in an individual with Bloom's syndrome.Bloom's syndrome (BS) is a rare recessive disorder caused by germline mutation of the BLM gene. Individuals with BS manifest growth retardation, immunodeficiency, and a predisposition to cancer. In this report, we describe an individual with BS and multiple colonic adenomas reminiscent of familial adenomatous polyposis coli (FAP). Molecular studies revealed APC mutations in 4 of 6 adenomas, including 2 adenomas with the identical APC mutation and microsatellite instability in 1 of 6 adenomas. These results demonstrate similar pathways to colorectal neoplasia in BS as in the normal population and suggest that individuals with BS may be particularly susceptible to colorectal neoplasia.- - - - - - - - - - ranking = 0.00018462894876729keywords = instability (Clic here for more details about this article) |
4/6. bloom syndrome: multiple retinopathies in a chromosome breakage disorder.AIM: To describe multiple retinal abnormalities in a patient with bloom syndrome, including early macular drusen, diabetic retinopathy, and the onset of leukaemic retinopathy. methods: Clinical data were collected over 1 year of follow up, and ocular abnormalities in bloom syndrome were reviewed from the literature. RESULTS: A 39 year old man with a rare autosomal recessive "chromosome breakage" syndrome was followed. A variety of ocular findings have been reported in bloom syndrome; this patient had hard drusen in both maculae, non-proliferative diabetic retinopathy, and haemorrhagic retinopathy as a herald of acute lymphocytic leukaemia. CONCLUSIONS: bloom syndrome is a rare disorder of genomic instability, in which a variety of ocular abnormalities have been found. Described here are multiple retinal manifestations arising from characteristic systemic associations of diabetes mellitus and leukaemia, as well as macular hard drusen.- - - - - - - - - - ranking = 0.00019725749907312keywords = instability, genomic (Clic here for more details about this article) |
5/6. retinoblastoma in association with the chromosome breakage syndromes Fanconi's anaemia and Bloom's syndrome: clinical and cytogenetic findings.Two children presenting with sporadic unilateral retinoblastoma and exhibiting a high degree of chromosome breakage were noted to have unusual facies, microcephaly and abnormal skin pigmentation. In the first child the pattern of both spontaneous and mitomycin-C-induced chromosome breakage was characteristic of Fanconi's anaemia although the degree of breakage was extreme. She also exhibited a striking increase in X-ray-induced chromosomal damage in G0 lymphocytes as measured by dicentric formation and increase in chromatid-type aberrations. She had a number of typical clinical features, including cafe-au-lait patches and abnormalities involving the kidney; however, she demonstrated neither the hypoplasia of radius and thumb nor the typical aplastic phase of this disorder. At age 22 months the child became anaemic with trilineage myelodysplasia, which was rapidly followed by the development of acute myeloblastic leukaemia. The early onset (at age 4 months) of retinoblastoma may have been associated with the underlying genomic instability. The second child exhibited a pattern of chromosome breakage characteristic of Bloom's syndrome, in addition to a moderate increase in damage induced by mytomycin-C. She had the typical stunted growth and malar hypoplasia of Bloom's syndrome although she did not demonstrate the frequently described erythematous 'butterfly rash' Although patients with Fanconi's anaemia and Bloom's syndrome are recognised to be at an increased risk of cancer, retinoblastoma has not previously been described in patients with either condition. We suggest that underlying recessive chromosome breakage syndromes may be underdiagnosed in paediatric cancer patients, with important implications for prognosis and genetic counselling.- - - - - - - - - - ranking = 1keywords = genomic instability, instability, genomic (Clic here for more details about this article) |
6/6. microsatellite instability in B-cell lymphoma originating from bloom syndrome.bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by lupus-like erythematous telangiectasias of the face, sun sensitivity, stunted growth infertility and immunodeficiency. In addition, BS patients are highly predisposed to cancers. Although recently the causative gene of BS (BLM) was identified as a DNA helicase homologue, the function of BLM in dna replication has not been elucidated. In this study, p53 mutation and microsatellite instability in B-cell lymphomas originating from 2 sibling BS patients were investigated. In the originally developed tumor of both patients, no p53 mutation was detected. In one patient, however, after treatment by ionizing radiation the B-cell lymphoma recurred, showing a 9-bp deletion in exon 7. In lymphoma cells and an EB-virus-transformed cell line from BS lymphocytes of this patient, microsatellite instability was also detected from the reduced length of microsatellite DNA markers, although in the other patient microsatellite instability was not detected. Thus, 2 B-cell lymphomas, despite having the same BLM mutation, showed different phenotypes in terms of p53 mutation and microsatellite instability.- - - - - - - - - - ranking = 0.0014770315901383keywords = instability (Clic here for more details about this article) |