Vetro Annalisa, Manolakos Emmanouil, Petersen Michael B, Thomaidis Loretta, Liehr Thomas, Croci Gianfranco, Franchi Fabrizia, Marinelli Maria, Meneghelli Emanuela, Dal Bello Babara, Cesari Stefania, Iasci Angela, Arrigo Giulia, Zuffardi Orsetta
Medical Genetics, University of Pavia, Pavia, Italy.
Eur J Med Genet. 2012 Mar;55(3):185-90. doi: 10.1016/j.ejmg.2012.01.010. Epub 2012 Jan 28.
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.
小额外标记染色体(sSMC)的传统分类方法大多基于荧光原位杂交(FISH)技术,既耗时又往往不足以全面了解这类重排的真正复杂性。我们描述了四条额外标记染色体,经比较基因组杂交阵列(array-CGH)分析后,相对于传统细胞遗传学和FISH研究的早期分类,其解读有很大不同,报告了两种传统方法未发现DNA含量的复杂标记类型:1. sSMC包含同一染色体的非连续区域;2. 最初被解释为额外的15号染色体缺失(del(15))的sSMC,结果是一条衍生的15号染色体,其上附着了另一条染色体的部分片段。所有这些可能都源自部分三体拯救事件,进一步证明了种系染色体失衡在胚胎发育过程中会经历剧烈的重排,导致意想不到的复杂性,并改变了目前关于额外标记染色体组成的观点。