The Cytogenetics Laboratory provides chromosome analysis of peripheral blood, bone marrow, tissues, and other clinical specimens. Special techniques such as high resolution banding or fluorescence in situ hybridization (FISH) are used as warranted in analysis of these specimens.
For chromosome analysis, at least 20 metaphase cells are counted. Every chromosome pair is microscopically analyzed band-for-band at the 550 band level of resolution, where possible, and at least two karyotypes are prepared. Giemsa trypsin banding (G-banding) is the method routinely employed; Q-banding for Y-chromatin analysis as well as additional banding techniques (e.g., C, NOR, R banding) are utilized when necessary to verify or augment G-banding studies. With certain conditions, an additional cell count and/or special stains or appropriate FISH testing will be performed.
FISH testing is available as an adjunct to Chromosome Analysis for a wide range of microdeletion syndromes, such as DiGeorge, Prader-Willi, Angelman, Smith-Magenis, Miller-Dieker, and Williams Syndromes.
FISH oncology probes are useful as an adjunct to Chromosome Analysis for assisting in diagnosis and classification of malignant hematologic disorders and certain solid tumors, evaluating prognosis and monitoring treatment. For example, identification and monitoring of the BCR/ABL fusion gene in patients with chronic myelogenous leukemia or acute lymphocytic leukemia, for new diagnosis of APL using a probe for PML/RARA, and for detecting the cryptic t(12;21) in pediatric ALL. The following FISH oncology probes are available: BCR/ABL [t(9;22)], PML/RARA [t(15;17)], MLL [t(11q23)], del(13q), IGH/CCND1 [t(11;14)], TEL/AML1 [t(12;21)], FIP1L1-PDGFRA [del(4q12)]. Additional probes may also be available as clinically indicated; contact MLabs or the Cytogenetics laboratory for additional information.
Specimens submitted to the Cytogenetics Laboratory must be appropriately labeled and accompanied by a properly completed requisition. As cytogenetic techniques are continuously being refined, a pertinent clinical history is imperative to guiding proper handling of clinical specimens; include the reason for requesting cytogenetic analysis, and pertinent clinical or family history.