A new multicolor-FISH approach for the characterization of marker chromosomes: centromere-specific multicolor-FISH (cenM-FISH)

Centromere-specific multi-color FISH (cenM-FISH) is a new multicolor FISH t echnique that allows the simultaneous characterization of all human centrom eres by using labeled centromeric satellite DNA as probes. This approach al lows the rapid identification of all human centromeres by their individual pseudo-coloring in one single step and is therefore a powerful tool in mole cular cytogenetics. CenM-FISH fills a gap in multicolor karyotyping using W CP probes and distinguishes all centromeric regions apart from the evolutio nary highly conserved regions on the chromosomes 13 and 21. The usefulness of the cenM- FISH technique for the characterization of small supernumerary marker chromosomes with no (or nearly no) euchromatin and restricted amoun ts of available sample material is demonstrated in prenatal, postnatal, and tumor cytogenetic cases. In addition, rarely described markers with the in volvement of heterochromatic material inserted into homogeneously staining regions could be identified and characterized by using the cenM-FISH techni que.