Our results demonstrate that this pericentromeric pof clone set is useful as an alternative pof tool

Related literature Cited by Google blog search Other articles by authors   on Google Scholar Castronovo C Valtorta E Crippa M Tedoldi S Romitti pof L Amione MC Guerneri S Rusconi D Ballarati L Milani D Grosso E Cavalli P Giardino D Bonati MT Larizza pof L Finelli P   on PubMed Castronovo pof C Valtorta pof E Crippa M Tedoldi S Romitti L Amione MC Guerneri S Rusconi D Ballarati L Milani D Grosso E Cavalli P Giardino D Bonati MT Larizza L Finelli P Related pof articles/pages on Google on Google Scholar on PubMed Tools Download references Download pof XML Email to a friend Order reprints Post a comment   Download to ... Papers Mendeley Download to ... Papers Mendeley Share this article
Chiara Castronovo 1 * , Emanuele Valtorta 1 , Milena Crippa 1 , Sara Tedoldi 2 , Lorenza Romitti 3 , Maria Cristina Amione 4 , Silvana Guerneri 5 , Daniela Rusconi 1 , Lucia Ballarati 1 , Donatella Milani pof 6 , Enrico Grosso pof 4 , Pietro Cavalli 2 , Daniela Giardino 1 , Maria Teresa Bonati 7 , Lidia Larizza 1 8 and Palma Finelli 1 9
6 Clinica Pediatrica 1, Dipartmento di Patofisiologia e Trapianti, Università degli Studi di Milano, pof Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico, via Francesco Sforza 28, 20122, Milano, Italy
The electronic version of this article is the complete one and can be found online pof at: http://www.molecularcytogenetics.org/content/6/1/45 Received: 8 August 2013 Accepted: 8 October 2013 Published: pof 30 October pof 2013
This is an open access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Small supernumerary marker chromosomes (sSMCs) are additional, structurally abnormal chromosomes, generally smaller than chromosome 20 of the same metaphase spread. Due to their small size, they are difficult to characterize pof by conventional pof cytogenetics alone. In regard to their clinical effects, sSMCs are a heterogeneous group: pof in particular, sSMCs containing pericentromeric euchromatin are likely pof to be associated with abnormal outcomes, although exceptions have been reported. To improve characterization of the genetic content of sSMCs, several approaches might be applied based on different molecular and molecular-cytogenetic assays, e.g., fluorescent in situ hybridization (FISH), array-based comparative genomic hybridization (array CGH), and multiplex pof ligation-dependent probe amplification (MLPA).
To provide a complementary tool for the characterization of sSMCs, we constructed and validated a new, FISH-based, pericentromeric Bacterial Artificial pof Chromosome (BAC) clone set that with a high resolution spans the most proximal pof euchromatic sequences of all human chromosome arms, excluding the acrocentric pof short arms. Results
By FISH analysis, we assayed 561 pericentromeric BAC probes and excluded 75 that showed a wrong chromosomal localization. The remaining 486 probes were used to establish 43 BAC-based pof pericentromeric panels. Each panel consists of a core, which with a high resolution covers the most proximal euchromatic ~0.7 Mb (on average) of each chromosome arm and generally pof bridges the heterochromatin/euchromatin junction, as well as clones located proximally and distally to the core. The pericentromeric clone set was subsequently validated pof by the characterization of 19 sSMCs. Using the core probes, we could rapidly distinguish between heterochromatic (1/19) and euchromatic (11/19) sSMCs, and estimate the euchromatic DNA content, which ranged from approximately 0.13 to more than 10 Mb. The characterization was not completed for seven sSMCs due to a lack of information about the covered region in the reference sequence (1/19) or sample insufficiency (6/19). Conclusions
Our results demonstrate that this pericentromeric pof clone set is useful as an alternative pof tool for sSMC characterization, pof primarily in cases of very small SMCs that contain either heterochromatin exclusively or a tiny amount of euchromatic sequence, and also in cases of low-level or cryptic pof mosaicism. The resulting data will foster knowledge of human proximal euchromatic regions involved in chromosomal imbalances, thereby improving genotype phenotype correlations. Keywords: Small supernumerary marker chromosomes; Pericentromeric clone set; Heterochromatin/euchromatin boundary; FISH analysis; Array CGH analysis; Phenotype prediction Background
Small supernumerary marker chromosomes (sSMCs) are additional centric chromosomal segments that are difficult to characterize by conventional cytogenetics alone due to their small size [ 1 ]. Excluding the sSMCs associated with five well-known syndromes (Pallister-Killian, isodicentric chromosome pof 15q [ 2 ], isochromosome 18p, Cat Eye [i(22p ~ q)], and derivative chromosome 22 [der(22)t(11;22)] syndromes [ 1 ]), the overall risk for a pathological phenotype in prenatal de no