Objective: To explore the incidence of chromosome 1 abnormality in myelodysplastic syndrome（MDS）to couple its association with clinical presentation and prognosis.
Methods: R- band karyotype analyses were performed in 672 cases of MDS between 2010 and 2013. Clinical data of those with abnormal chromosome l were collected and then analyzed factors affecting the prognosis.
Results: Of 672 cases of patients with MDS, chromosome 1 aberration［der（1）, dup（1）, －1 were most frequent］ were found in 41（6.1%）cases. 1q trisomy was found in 18/41（43.9%）cases, and the most common patterns were duplication of the long arm as well as unbalanced translocation with other chromosomes. Of 41 patients with chromosomal 1 abnormality, 32 cases were accompanied with other chromosomal aberration, usually involving 3 or more abnormal chromosomal karyotypes, e.g., chromosome 8, 7 abnormalities. According to IPSS-R scoring system, 19 patients were diagnosed with very high risk, 10 patients high risk, 10 patients intermediate risk and 2 patients low risk MDS. 9 patients transformed into acute leukemia with median transforming time of 7.18（0.56-54.28）months. Median survival of 36 cases after 2010 was 17.48（95% CI 14.38-20.58）months. There were significant differences on median survival between RAEB and non-RAEB groups（χ²=10.398, P=0.001）, and between with more than 3 chromosome abnormalities and with less than 3 groups（χ²=3.939, P=0.047）. RAEB was identified as an independent risk factor for the prognosis of MDS with chromosome 1 abnormality.
Conclusion: Chromosome 1 aberration was not rare in MDS. 1q trisomy was the most common abnormal karyotype in China, which often accompanied with other chromosomal abnormalities. The prognosis of MDS patients with chromosome 1 abnormality was poor, especially worse in those diagnosed with RAEB-1, RAEB-2 and with more than 3 chromosome abnormality. For patients whose percentage of bone marrow blasts less than 5%, the prognosis of patients with 1q trisomy was better than those without 1q trisomy. RAEB was identified as an independent risk factor for the prognosis of MDS with chromosome 1 abnormality.
目的: 观察1号染色体异常在骨髓增生异常综合征(MDS)中的发生率，并分析其临床及细胞遗传学特征。
方法: 回顾性分析2010年至2013年672例MDS患者临床资料，研究伴l号染色体异常的发生率及其临床、细胞遗传学特征，分析影响预后的因素。
结果: 672例MDS患者中伴1号染色体异常41例(6.1%)，其中难治性贫血(RA)6例、难治性贫血伴有环状铁粒幼红细胞(RARS)2例、难治性血细胞减少伴有多系发育异常(RCMD)9例、难治性贫血伴有原始细胞过多(RAEB)-1 10例、RAEB-2 13例、MDS不能分类(MDS-U)1例。1号染色体异常以der(1)、dup(1)、−1多见，1q三体18例(43.9%)，以1q片段重复和1q与其他染色体发生不平衡易位多见。32例合并有其他染色体异常，多涉及3个及以上异常核型。9例转变为急性白血病(转白)，中位转白时间为7.18(0.56~54.28)个月；36例患者纳入生存分析，中位生存时间为17.48 (95% CI 14.38~20.58)个月。RAEB组(RAEB-1、RAEB-2)、染色体异常>3种组中位生存时间分别短于非RAEB组(RA、RARS、RCMD、MDS-U)、染色体异常≤3种组(χ2=10.398，P=0.001；χ2=3.939，P=0.047)。RAEB是影响l号染色体异常MDS患者预后的独立危险因素。
结论: 1号染色体异常在MDS中并不罕见，以1q三体最为常见，且常伴其他异常核型。伴1号染色体异常MDS患者总体预后较差，RAEB是伴1号染色体异常MDS患者独立预后因素。