Molecular Cytogenetics (Apr 2008)

Complex rearranged small supernumerary marker chromosomes (sSMC), three new cases; evidence for an underestimated entity?

  • Mkrtchyan Hasmik,
  • Kosyakova Nadezda,
  • Gross Madeleine,
  • Rodriguez Laura,
  • Anderson Jasen,
  • Nandini Adayapalam,
  • Binkert Franz,
  • Fluri Simon,
  • Trifonov Vladimir,
  • Ewers Elisabeth,
  • Reich Daniela,
  • Weise Anja,
  • Liehr Thomas

DOI
https://doi.org/10.1186/1755-8166-1-6
Journal volume & issue
Vol. 1, no. 1
p. 6

Abstract

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Abstract Background Small supernumerary marker chromosomes (sSMC) are present ~2.6 × 106 human worldwide. sSMC are a heterogeneous group of derivative chromosomes concerning their clinical consequences as well as their chromosomal origin and shape. Besides the sSMC present in Emanuel syndrome, i.e. der(22)t(11;22)(q23;q11), only few so-called complex sSMC are reported. Results Here we report three new cases of unique complex sSMC. One was a de novo case with a dic(13 or 21;22) and two were maternally derived: a der(18)t(8;18) and a der(13 or 21)t(13 or 21;18). Thus, in summary, now 22 cases of unique complex sSMC are available in the literature. However, this special kind of sSMC might be under-diagnosed among sSMC-carriers. Conclusion More comprehensive characterization of sSMC and approaches like reverse fluorescence in situ hybridization (FISH) or array based comparative genomic hybridization (array-CGH) might identify them to be more frequent than only ~0.9% among all sSMC.