正常核型骨髓增生异常综合征患者的基因变异谱系分析

Mutation analysis of 77 patients with normal-karyotype myelodysplastic syndrome

目的 探讨正常核型的骨髓增生异常综合征(myelodysplastic syndrome,MDS)患者多个肿瘤基因的变异情况.方法 应用高通量DNA测序技术检测49种靶基因;采用基因组DNA-PCR联合Sanger测序法检测CALR基因第9外显子、NPM1基因第12外显子、FLT3-ITD及CEBPA的TAD、BZIP两个功能结构域的变异.结果 77例患者中,总的基因变异发生率为80.5%(62/77),其中,43.7%的患者至少携带≥3种基因变异,每例患者平均发生2.21个基因变异.基因变异检出率由高到低依次为RUNX1(23.4%,18/77)、ASXL1(18.2%,14/77)、NPM1(15.6%,12/77)、U2AF1(15.6%,12/77)、DNMT3A(11.7%,9/77)、BCOR(11.7%,9/77)、TET2(10.4%,8/77).SF3B1变异的中位年龄明显大于ASXL1变异者,差异有统计学意义(P=0.023),DNMT3A变异的血小板中位水平高于BCOR变异者(P=0.02);基因变异个数及常见基因变异率在年龄<60岁及≥60岁组中的差异无统计学意义(P均>0.05).67例有效随访患者中,20例发生白血病转化,平均转化时间为5.3个月,其中,RUNX 1、U 2AF 1、FLT3基因变异与转白率呈显著正相关(r分别为0.233、0.232、0.245,P<0.05).结论 正常核型MDS患者多基因变异共存发生率较高,其中,部分基因变异与年龄及白血病转化有一定相关性.

Objective To carry out mutation analysis for patients with myelodysplastic syndromes(MDS)and a normal karyotype.Methods Targeted capture and next-generation sequencing(NGS)was carried out using a customized 49-gene panel.FLT3 internal tandem duplication(FLT3-ITD),CALR,NPM1 and CEBPA mutations were detected by PCR and Sanger sequencing.Results Sixty two patients(80.5%)were found to harbor at least one mutation.Each patient has carried 2.21 mutations in average.Coexistence of≥3 mutations was common(43.7%).The most commonly mutated genes were RUNX1(23.4%,18/77),ASXL1(18.2%,14/77),NPM1(15.6%,12/77),U2AF1(15.6%,12/77),DNMT3A(11.7%,9/77).Patients with SF3B1 mutations were significantly older than those with ASXL1 mutations(P=0.023).Mutations of the DNMT3A gene were significantly associated with the blood platelet level compared with BCOR mutations(P=0.02).No significant difference was found in the number and rate of mutations between those under or above 60-year-old.Among 67 patients with clinical follow-up,20(29.8%)has transformed to acute myeloid leukemia,and the time of transformation has ranged from 1&nbsp;to 44 months,with a average of 5.3 months.RUNX1,U2AF1 and FLT3 mutations are associated with leukemic transformation.Conclusion Coexistence of≥3 mutations are frequent among patients with normal-karyotype MDS.Certain mutations are associated with age and leukemic transformation.