Trifonov, VladimirFluri, SimonBinkert, FranzNandini, AdayapalamAnderson, JasenRodriguez, LauraGross, MadeleineKosyakova, NadezdaMkrtchyan, HasmikEwers, ElisabethReich, DanielaWeise, AnjaLiehr, Thomas2019-01-302019-01-302008-04-15Mol Cytogenet. 2008 Apr 15;1:6.1755-8166http://hdl.handle.net/20.500.12105/7024BACKGROUND: Small supernumerary marker chromosomes (sSMC) are present ~2.6 x 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.engVoRhttp://creativecommons.org/licenses/by/4.0/Atribución 4.0 Internacional1847131811610.1186/1755-8166-1-61755-8166Molecular cytogeneticsopen access