二例伴有i(20q-)重复的骨髓增生异常综合征的临床和实验研究

目的探讨伴有i(20q-)重复的骨髓增生异常综合征(MDS)临床和实验室特征。方法骨髓细胞经直接法和24h培养后按常规方法制备染色体，用RHG显带技术进行核型分析，并以20q端粒探针和20q12单一序列探针进行荧光原位杂交(FISH)检测。结果2例的临床和血液学改变符合MDS诊断；染色体核型分析揭示2例患者均有i(20q-)重复：例1为46，XX，del(20)?i(20q-)6]／46，idem，der(6)i(6p)1]／47，idem， der(20)?i(20q-)3]／47，idem，der(6)i(6p)， dei(20)?i(20q-)20]，例2为45，XY，-7，der(20)?i(20q-)17]／46，idem， der(20)?j(20q-)3]。其中1例患者经双色FISH检测证实两个衍生的20号染色体为伴有中间缺失的20号长臂等臂染色体。结论i(20q-)重复是MDS的一种少见的再现性的核型异常，预后不佳。

Clinical and experimental study of two cases of myelodysplastic syndromes with double isochromosome 20q- anomaly

Objective To explore the clinical and laboratory characteristics of two myelodysplastic syndromes (MDS) patients with double isochromosome 20q-anomaly. Methods Bone marrow cell chromosome preparations were made with both direct method and short-term culture. Karyotype analysis was performed by R-banding technique, and dual-color FISH (fluorescence in situ hybridization) by using a 20q telomeric probe and a sequence-specific probe for 20q12. Results The clinical and hematological findings were comparable with diagnosis of MDS. Karyotype analysis showed that both patients had double isochromosome 20q-anomaly: case 1 is 46, XX, der(20)?i (20q-)6]/ 46, idem, der (6)i (6p)1]/ 47, idem, +der (20)?i (20q-)3]/ 47, idem, der (6)i (6p), +der (20)?i (20q-)20]; case 2 is 45, XY,-7, der (20)?i (20q-)17]/46, idem, +der (20)?i(20q-)3]. Two derivative chromosomes 20 were proved 20q isochromosomes with interstitial deletions by dual-color FISH in one patient. / 46, idem, der (6)i (6p)1]/ 47, idem, +der (20)?i (20q-)3]/ 47, idem, der (6)i (6p), +der (20)?i (20q-)20]; case 2 is 45, XY,-7, der (20)?i (20q-)17]/46, idem, +der (20)?i(20q-)3]. Two derivative chromosomes 20 were proved 20q isochromosomes with interstitial deletions by dual-color FISH in one patient. / 47, idem, der (6)i (6p), +der (20)?i (20q-)20]; case 2 is 45, XY,-7, der (20)?i (20q-)17]/46, idem, +der (20)?i(20q-)3]. Two derivative chromosomes 20 were proved 20q isochromosomes with interstitial deletions by dual-color FISH in one patient. Conclusions Double isochromosome 20q-anomaly is a rare recurrent karyotype abnormality in MDS, and signals a poor prognosis.