t(8;21)隐匿复杂变异易位-t(8;4;21)的遗传学及临床研究报道

Genetic study of rare t(8;4;21)(q22;p15;q22):a cryptic and complex variant of t(8;21)

目的:报道1例具有隐匿复杂变异易位-t(8;4;21)的M2型急性髓性白血病的遗传学及临床特征。方法:利用骨髓细胞短期培养法制备染色体标本;应用G显带技术进行核型分析;利用双色双融合荧光原位杂交检测RUNX1/RUNX1T1融合基因;采用实时荧光定量RT-PCR检测RUNX1/RUNX1T1融合基因转录本。结果:患者最初核型结果为46,XX,t(4;8)(p15;q22)[3]/45,sl,-X[17],但双色双融合荧光原位杂交证实存在RUNX1/RUNX1T1融合基因和变异易位,同时实时荧光定量RT-PCR检测到RUNX1/RUNX1T1融合基因转录本。因此核型结果最终修订为:46,XX,t(8;4;21)(q22;p15;q22)[3]/45,sl,-X[17],是一种t(8;21)隐匿复杂变异型易位。结论:联合双色双融合荧光原位杂交和实时荧光定量RT-PCR检测有助于鉴定出变异型t(8;21)易位。

Objective:To report the genetic characters of acute myeloid leukemia with t(8;4;21),a cryptic complex variant of t(8;21).Method:Chromosome specimen was prepared by short-term culture of bone marrow cells,and karyotype analysis was carried out using G-banding techniques.Fluorescence in situ hybridization(FISH)was performed using dual color dual fusion probe to detect fusion gene RUNX1/RUNX1 T1,and real-time RT-PCR was performed to detect the transcripts of this fusion gene.Result:The original karyotype of this patient was 46,XX,t(4;8)(p15;q22)[3]/45,sl,-X[17].While dual color dual fusion FISH suggested the existence of fusion gene RUNX1/RUNX1 T1 and a variant of the translocation,meanwhile transcripts of this fusion gene were detected by real-time RT-PCR.Therefore,the revised karyotype was 46,XX,t(8;4;21)(q22;p15;q22)[3]/45,sl,-X[17],which is a very rare cryptic and complex variant of t(8;21).Conclusion:Combined tests of dual color dual fusion FISH and real-time RT-PCR contribute to identification of rare variants of t(8;21).