Rapid identification of marker chromosomes using primed in situ labeling (PRINS).

Primed in situ labeling (PRINS) is a relatively new technology with wide-ranging applications in clinical cytogenetics. Using PRINS, we have identified the chromosomal origin of marker chromosomes in three patients. In the first patient with primary amenorrhea, we were able to confirm the marker chromosome as originating from an X. In the second (prenatal) case, PRINS allowed us to determine rapidly the origin of the marker as a Y chromosome. In the third patient with minor anomalies, the marker was identified as derived from a chromosome 18. In all three cases, application of PRINS permitted us to characterize the marker chromosomes within 1 hour after the slides were prepared. The methodology is simple, has added advantages over conventional fluorescence in situ hybridization (FISH), and can be used as a viable and effective alternative to FISH in clinical cytogenetic diagnosis.