Mechanisms of Origin and Clinical Effects of Multiple Small Supernumerary Marker Chromosomes, Each Derived from a Different Chromosome
Abstract
Small supernumerary marker chromosomes (sSMCs) are centric chromosome fragments additionally present in an otherwise normal human chromosome set that cannot be characterized by classical cytogenetic techniques alone. The majority of sSMCs are not yet related to a defined clinical phenotype. We compiled from the literature all 78 cases with multiple sSMCs per cell in which the chromosomal origin of the sSMCs has been identified. The number of sSMCs varies from 2 to 7; 64% have 2 sSMCs, 14% have 3 [...]