engleski

FISH investigation of chromosome abnormalities in clinical cytogenetics

From NOvember20, 1996 to June 1, 2001 we have performed 906 molecular cytogenetic studies in 288 samples of peripheral blood, 49 amniotic fluids, 4 VCS, 4 chordocentesis and 10 tissues, 548 bone marrows and only 3 solid tumours. A variety of probes were used with numerous applications such as wcp, alpha satellite and specific region probes. Hybridised signals were scored under a fluorescence microscope using appropriate absorption and excitation filters. Microdeletion syndromes, rearrangements and marker chromosomes have been detected or chracterized by those techniques. Examples of chromosome markers include 29 small markers derived from chromosome 15, 22, 21, X and Y, a small marker 22 in case that also had a translocation (X;17). Several cases with "de novo" rearrangements were recognized. We found that an add(9)(p14;24) was a der(9)t(4;9) with monosomy 9p and partial trisomy 4p,der(13) was inversion duplication of 13(q22),cx translocation t(7;4;14) with insertion hence a partial trisomy of der 4, derivate chromosome 1 with centromere 15 on the terminal part of 1(p36) and that Elastin locus was disrupted by translocation t(7;14)(q11.23;p12). Molecular cytogenetic analysis of 12 workers exposed to the constant level of vinyl-chloride monomer were peroformed for detection of stable genome damage in order to estimate the genome risk. FISH studies in bone marrow and solid tumours characterised the origin of multiplechromosome rearrangements and helped in the interpretation of the diagnosis and/or prognosis. FISH was used for both, initial detection of specific abnormality with major prognostic and biologic impact and to the follow-up of treated patients by detection of MRD and identification of the origin of bone marrows cells following stem cell transplantation. I-FISH permits the evaluation of a large number of cells in detection of numerical changes and specific translocations. Hybridised signals were scored in about 100-700 interphase nuclei for each patient, with increased precision, since hundereds of cells(including nondividing cells) can be examined in a short time. Metaphase FISH was useful in detection of cryptic rearrangements and identification of marker chromosomes. The subtelomeres has been investigated with PNA probes in children leukemia. We concluded that the availability of new probes and the use of specialised techniques, such as FISH, M-FISH have improved significantlly the services offered by clinical cytogenetic laboratory in our hospital.

FISH; clinical cytogenetics

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