title: Unexpected results in the constitution of small supernumerary marker chromosomes.
abstract: Traditional approaches for the classification of Small Supernumerary Marker Chromosomes (sSMC), mostly based on FISH techniques, are time-consuming and not always sufficient to fully understand the true complexity of this class of rearrangements. We describe four supernumerary marker chromosomes that, after array-CGH, were interpreted rather differently in respect to the early classification made by conventional cytogenetics and FISH investigations, reporting two types of complex markers which DNA content was overlooked by conventional approaches: 1. the sSMC contains non-contiguous regions of the same chromosome and, 2. the sSMC, initially interpreted as a supernumerary del(15), turns out to be a derivative 15 to which the portion of another chromosome was attached. All are likely derived from partial trisomy rescue events, bringing further demonstration that germline chromosomal imbalances are submitted to intense reshuffling during the embryogenesis, leading to unexpected complexity and changing the present ideas on the composition of supernumerary marker chromosomes.
authors.affiliation: Medical Genetics, University of Pavia, Pavia, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Vetro
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Manolakos
authors.forename: Michael B
authors.initials: MB
authors.lastname: Petersen
authors.forename: Loretta
authors.initials: L
authors.lastname: Thomaidis
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Croci
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Franchi
authors.forename: Maria
authors.initials: M
authors.lastname: Marinelli
authors.forename: Emanuela
authors.initials: E
authors.lastname: Meneghelli
authors.forename: Babara
authors.initials: B
authors.lastname: Dal Bello
authors.forename: Stefania
authors.initials: S
authors.lastname: Cesari
authors.forename: Angela
authors.initials: A
authors.lastname: Iasci
authors.forename: Giulia
authors.initials: G
authors.lastname: Arrigo
authors.forename: Orsetta
authors.initials: O
authors.lastname: Zuffardi
mesh_terms: D000328:Adult; D002648:Child; D002877:Chromosomes, Human / Q000235:genetics*; D055028:Comparative Genomic Hybridization; D005260:Female; D005333:Fetus; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D014314:Trisomy