摘要介绍世界卫生组织（WHO）对骨髓增生异常综合征（MDS）中原因不明的特发性血细胞减少（ICUS）和方向不明的克隆造血（CHIP）的解读。MDS的诊断基于2个特征，即病态造血的证据和克隆造血的证据。病态造血用于描述伴1系或以上血细胞系列形态学异常。MDS中检测到的绝大多数染色体异常或基因损伤不是特异性的，而在缺少形态学或无细胞遗传学异常的情况下，排除或明确MDS的诊断则极具挑战性。为了描述可疑但未确诊的MDS，引入了意义不明的ICUS的概念。 CHIP目前定义那种未明确诊断为肿瘤，但是携带与血液系统肿瘤相关体细胞突变基因的状态。大规模平行测序技术的推广，为髓系肿瘤临床治疗提供了良机。尽管关于克隆造血的肿瘤潜能和其意义的问题仍有待于说明，但是基因测序在鉴别克隆性病态造血、非克隆性血细胞减少、由于衰老或其他原因导致的获得性骨髓衰竭相关的克隆造血等方面是非常有价值的。

abstractsThe progress in recognition of idiopathic cytopenias of undetermined significance (ICUS) and clonal hematopoiesis of indeterminate potential (CHIP) from WHO are reviewed. However, biologic and analytic limitations have emerged in the criteria for myelodysplastic syndromes (MDS). The provisional category of ICUS has been proposed to describe patients with MDS which is possible but without definite diagnosis. To formulate the diagnosis of ICUS, a thorough diagnostic work-up will be required and repeated tests should be performed to reach a conclusive diagnosis. Recent studies have provided consistent evidence of age-related hematopoietic clones, driven by mutations of genes that are recurrently mutated in myeloid neoplasms and associated with an increase in the risk of hematologic cancer. The spreading of massively parallel sequencing techniques will offer translational opportunities in the clinical approach to myeloid neoplasms.