伴等臂20q-髓系疾病的临床和分子细胞遗传学特征

目的 探讨7例以i(20q-)异常为特征的髓系疾病的临床和分子细胞遗传学特征。方法 采用骨髓细胞直接法和／或短期培养法按常规制备染色体,采用R显带技术进行核型分析,以20q亚端粒探针和20q12单一序列DNA探针进行双色荧光原位杂交(D-FISH)检测。结果 7例患者中骨髓增生异常综合征(MDS)6例,急性髓细胞白血病(AML)1例。3例现尚存活,其余4例均已死亡,他们的生存期分别为6个月(例1),7个月(例2),17d(例4),28d(例5)。染色体核型分析揭示7例均丢失1个正常20号染色体而代之以1或2个比20号染色体还小的中着丝粒等臂染色体,其中6例经FISH检查证实它是伴有20q12中间缺失的20q等臂染色体ider(20)(q10)del(20)(q11q13),即i(20q-)。结论 i(20q-)核型是一种新的少见的再现性染色体异常,它可能和髓系疾病及不良预后有特别的联系。

Clinical and molecular cytogenetic features of myeloid diseases characterized by i(20q-): a study of seven cases

OBJECTIVE: To investigate the clinical and molecular cytogenetic features of myeloid diseases characterized by i(20q-). METHODS: The clinical data of 7 patients with myeloid diseases, 6 with myelodysplastic syndrome (MDS) and one with acute myelocytic leukemia (AML), 4 males and 3 females, aged 51 - 74, were analyzed. Chromosome specimens were prepared by direct method and/or short-time culture of bone marrow cells. Karyotyping was performed by R banding technique. Two kinds of probes (20q subtelomere probe and 20q12 unique sequence probe) were used in dual-color fluorescence in situ hybridization (D-FISH) assay. RESULTS: Of the seven patients, 4 died and 3 survived by the end of this study. The patients survived for 6 months (case 1), 7 months (case 2), 17 days (case 4), and 28 days (case 5) respectively. Karyotype analysis showed that one of the normal chromosomes 20 was lost and substituted by one or two small metacentric isochromosomes smaller than the normal chromosome 20 in all these seven cases. It was proved to be ider(20)(q10) del(20)(q11q13), i(20q-) in six cases by D-FISH assay. CONCLUSION: i(20q-) is a novel and rare recurrent chromosome abnormality which may be specifically associated with myeloid diseases and poor prognosis.