Characterization of Small Supernumerary Marker Chromosomes By A Simple Molecular and Molecular Cytogenetics Approach

Small supernumerary marker chromosomes (sSMC) are still a major problem especially in prenatal cytogenetic diagnostics and counseling. These structurally abnormal chromosomes cannot be identified or characterized unambiguously by conventional banding cytogenetics alone, and are generally about the size of or smaller than a chromo some 20 in the same metaphase spread. We describe a straightforward algorithm, based on data from 2,211 reported cases (http://www.markerchromosomes.ag.vu) to quickly characterize the sSMC's chromosomal origin.