Centromeric association of small supernumerary marker chromosomes with their sister-chromosomes detected by three dimensional molecular cytogenetics

Autor: Roberta Santos Guilherme, Elisabeth Klein, Marina Manvelyan, Isabella Simonyan, Tatyana V. Karamysheva, Thomas Liehr, Ahmed B. Hamid
Rok vydání: 2012
Předmět:
Zdroj: Molecular Cytogenetics
Molecular Cytogenetics, Vol 5, Iss 1, p 15 (2012)
ISSN: 1755-8166
Popis: Background: Small supernumerary marker chromosomes (sSMC) are detected in 0.043% of general population and can be characterized for their chromosomal origin, genetic content and shape by molecular cytogenetic approaches. Even though recently progress was achieved towards genotype-phenotype-correlations of sSMC, nothing is known on the influence that an additional derivative extra chromosome has on the nuclear architecture. Results: Here we present the first three-dimensional interphase fluorescence in situ hybridization (FISH) studies for the nuclear architecture of sSMC. It could be shown that sSMC derived from chromosomes 15, 16 or 18 preferentially colocalized with one of their corresponding sister chromosomes. This was true in B- and Tlymphocytes as well as in skin fibroblasts. Additionally, a case with a complex sSMC with a karyotype 47,XY,+der (18)t(8;18)(8p23.2 ~ 23.1;18q11.1) was studied. Here the sSMC co-localized with one homologous chromosome 8 instead of 18. Conclusion: Overall, there is a kind of “attraction” between an sSMC and one of its homologous sister chromosomes. This seems to be transmitted by the euchromatic part of the sSMC rather than its heterochromatic one. Background Small supernumerary marker chromosomes (sSMC) are reported in 0.043% of newborn infants, 0.077% of prenatal cases, 0.433% of mentally retarded patients and 0.171% of subfertile people [1]. They are defined as structurally abnormal chromosomes that cannot be identified or characterized unambiguously by conventional banding cytogenetics alone, and are generally equal in size or smaller than a chromosome 20 of the same metaphase spread. sSMC are mostly detected unexpectedly in routine cytogenetics [2] and are not easy to correlate with a specific clinical outcome [3]. It is known that ~30% of sSMC are derived from chromosome 15; ~11% are i(12p)-, i.e. Pallister-Killian-, ~10%
Databáze: OpenAIRE
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