Fluorescence in situ hybridization in human genetic diagnostics

The field of genetic diagnostics incorporates a variety of methods that complement each other. Therefore, the development of new methods calls for a review of the advantages and limitations of established and new technologies. Fluorescence in situ hybridization ( FISH) is routinely applied in genetics. Custom designed and commercially available probes allow for nearly unlimited and targeted visualization of genomic DNA using either metaphase spreads, interphase nuclei, tissue sections, or living cells. FISH applications are particularly important for the detection of structural rearrangements such as microdeletions, translocations, inversions, and in-sertions, as well as for identification of marker chromosomes, characterization of chromosome breakpoints, and prenatal aneuploidy testing. Furthermore, the analysis of genetic heterogeneity, including mosaicism, is accomplished by evaluating single cells. FISH may also be combined with fluorescent antibodies against cell surface markers and correlated to specific morphologic features of cells and tissues.