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Updated: Aug 14, 2026

Chromosome Replicating Timing Combined with Fluorescent In situ Hybridization
Published on: December 10, 2012
Overrepresentation of small supernumerary marker chromosomes (sSMC) from chromosome 6 origin in cases with multiple
Thomas Liehr1, Heike Starke, Gabriele Senger
1Institut für Humangenetik und Anthropologie, D-07740 Jena, Germany. i8lith@mti.uni-jena.de
Abstract:
Small supernumerary marker chromosomes (sSMC) in human are defined as additional centric derivatives smaller than chromosome 20. In the majority of the cases only one sSMC is present, leading to a more or less stable karyotype of 47,XX,+mar or 47,XY,+mar. In approximately 1.4% of sSMC cases two or up to seven markers of different chromosomal origin are reported. According to the literature a sSMC(6) was present in 33% of the patients with multiple sSMC while sSMC(6) are observed in <1% of cases with a single sSMC. Currently there is no explanation for this striking observation. Here we report on one more unique case with two sSMC, one derived from #5 and the other from #6. Using microdissection/reverse painting, subcentromere-specific multicolor FISH (subcenM-FISH) and multicolor banding (MCB), they could be described as min or r(6)(::p11.1 --> q11.1::) and r(5)(::p11.1 approximately 12 --> q10::q10 --> p11.1 approximately 12::), respectively. Reversed array CGH using the DNA of the microdissected sSMC as probe confirmed the FISH results and enabled the rapid mapping of the breakpoints.
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