Mishra Shiba Ranjan, Rawal Leena, Othman Moneeb A K, Thatai Atul, Sarkar Aditi, Lal Vandana, Bhattacharya Saurabh Kumar
Department of Clinical Cytogenomics, National Reference Laboratory, Dr. Lal Path Labs Ltd., Block E, Sector 18, Rohini, New Delhi, 110085, India.
Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
Mol Cytogenet. 2021 May 21;14(1):28. doi: 10.1186/s13039-021-00541-6.
The translocation t(8;21)(q22;q22) is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML) sub type M2. About 3-5 % of cases with additional chromosomal abnormalities, including structural and numerical ones, are reported to include a complex translocation t(8;21;N).
Here we report a chromosome rearrangement observed in a 19 years-old female diagnosed with AML-M2. When subjected to (molecular) cytogenetic analyses a complex three-way translocation involving chromosomes 8, 17 and 21 was detected, forming not a t(8;21;17) as one would expect. Real time-polymerase chain reaction analysis using 6 AML specific markers showed the presence of RUNX1/RUNX1T1 fusion gene transcripts identical to those found in classical translocation t(8;21) coupled with presence of FLT3-ITD mutation identified by fragment analysis.
The present case highlights importance of complex rearrangements rarely encountered in AML, suggesting that all involved regions harbor critical candidate genes regulating the pathogenesis of AML, leading to novel as well as well-known leukemia associated chromosomal aberrations.
易位t(8;21)(q22;q22)是与急性髓系白血病（AML）M2亚型相关的最常见染色体异常之一。据报道，约3%-5%伴有其他染色体异常（包括结构和数量异常）的病例存在复杂易位t(8;21;N)。
我们在此报告一名被诊断为AML-M2的19岁女性中观察到的染色体重排。在进行（分子）细胞遗传学分析时，检测到涉及染色体8、17和21的复杂三向易位，并非如预期形成t(8;21;17)。使用6个AML特异性标志物进行实时聚合酶链反应分析显示，存在与经典易位t(8;21)中发现的相同的RUNX1/RUNX1T1融合基因转录本，同时通过片段分析鉴定出FLT3-ITD突变。
本病例突出了AML中罕见的复杂重排的重要性，表明所有涉及区域都含有调节AML发病机制的关键候选基因，导致了新的以及已知的与白血病相关的染色体畸变。
