Bint Susan M, Davies Angela F, Ogilvie Caroline Mackie
Cytogenetics department, GSTS-Pathology, Guy's and St, Thomas' Hospital NHS Foundation Trust, London SE1 9RT, UK.
Mol Cytogenet. 2013 Dec 5;6(1):55. doi: 10.1186/1755-8166-6-55.
Array comparative genomic hybridization (CGH) for high resolution detection of chromosome imbalance, and karyotype analysis using G-banded chromosomes for detection of chromosome rearrangements, provide a powerful diagnostic armoury for clinical cytogenetics. However, abnormalities detected by karyotype analysis cannot always be characterised by scrutinising the G-banded pattern alone, and imbalance detected by array CGH cannot always be visualised in the context of metaphase chromosomes. In some cases further techniques are needed for detailed characterisation of chromosomal abnormalities. We investigated seven cases involving structural chromosome rearrangements detected by karyotype analysis, and one case where imbalance was primarily detected by array CGH. Multicolor banding (MCB) was used in all cases and proved invaluable in understanding the detailed structure of the abnormalities.
Karyotype analysis detected structural chromosome rearrangements in 7 cases and MCB was used to help refine the karyotype for each case. Array CGH detected imbalance in an eighth case, where previously, G-banded chromosome analysis had reported a normal karyotype. Karyotype analysis of a second tissue type revealed this abnormality in mosaic form; however, MCB was needed in order to characterise this rearrangement. MCB provided information for the delineation of small deletions, duplications, insertions and inversions and helped to assign breakpoints which were difficult to identify from G-banded preparations due to ambiguous banding patterns.
Despite the recent advance of array CGH in molecular cytogenetics we conclude that fluorescence in situ hybridization, including MCB, is still required for the elucidation of structural chromosome rearrangements, and remains an essential adjunct in modern diagnostic laboratories.
用于高分辨率检测染色体失衡的阵列比较基因组杂交（CGH）以及使用G带染色体进行核型分析以检测染色体重排，为临床细胞遗传学提供了强大的诊断手段。然而，通过核型分析检测到的异常并非总能仅通过仔细观察G带模式来确定其特征，而通过阵列CGH检测到的失衡也并非总能在中期染色体的背景下直观呈现。在某些情况下，需要进一步的技术来详细表征染色体异常。我们研究了7例通过核型分析检测到结构染色体重排的病例，以及1例主要通过阵列CGH检测到失衡的病例。所有病例均使用了多色带分析（MCB），结果证明其在理解异常的详细结构方面具有重要价值。
核型分析在7例病例中检测到结构染色体重排，MCB用于帮助完善每个病例的核型。阵列CGH在第8例病例中检测到失衡，此前G带染色体分析报告核型正常。对第二种组织类型进行核型分析发现该异常呈嵌合形式；然而，需要MCB来表征这种重排。MCB为小缺失、重复、插入和倒位的描绘提供了信息，并有助于确定由于带型模式不明确而难以从G带制备物中识别的断点。
尽管阵列CGH在分子细胞遗传学方面取得了最新进展，但我们得出结论，包括MCB在内的荧光原位杂交对于阐明结构染色体重排仍然是必需的，并且仍然是现代诊断实验室的重要辅助手段。
