目的　阐明NOTCH1基因突变在儿童T细胞型急性淋巴细胞白血病（T-ALL）中的特征及临床意义。方法　通过对28例T-ALL患儿NOTCH1基因的异二聚体（HD）区及脯氨酸-谷氨酸-丝氨酸-苏氨酸（PEST）区测序，研究T-ALL患儿中NOTCH1基因突变的发生率、位点、类型及其与预后的相关性。结果　28例T-ALL患儿中，15例（51.57%）患儿的NOTCH1基因发生突变，均为杂合性突变。突变患儿入院时外周幼稚淋巴细胞比例及骨髓幼稚细胞比例与无突变患儿相比均明显升高（P<0.05）。28例患儿的一年缓解率为75.0%（21/28），其中突变患儿的一年缓解率为80.0%（12/15），无突变患儿为69.2%（9/13）。此外，3例复发的突变组患儿至一年随访时均已死亡（一年时病死率为20%），而4例复发的无突变患儿经再次化疗后至一年随访时均存活（一年时病死率为0%）。结论　儿童T-ALL患者中NOTCH1基因突变发生率高、位点多样；NOTCH1突变者初诊时疾病更严重，短期预后较好、而复发后挽救治疗预后更差的趋势。

Objective　To clarify the characteristics and clinical significance of the NOTCH1 mutations in childhood T-cell acute lymphoblastic leukemia (T-ALL). Methods　Amplify and sequence the heterodimerization (HD) domain and the proline- glutamicacid-serine-threonine (PEST) domain of the NOTCH1 gene in 28 T-ALL children, in order to explore the frequency, position and type of the mutations as well as their reletions with prognosis. Results　In 28 children with T-ALL, 15 cases (51.57%) had been identified the NOTCH1 mutations, all of which were heterozygous mutations. The lymphoblast counts in peripheral blood and bone marrow in the NOTCH1 mutant group at admission were significantly higher than in the non-mutant group (P<0.05). The 1-year remission rate in the 28 children with T-ALL was 75% (21/28), including 80% (12/15) in mutant group in which 3 patients relapsed and all of them died (1-year mortality 20%) and 69.20% (9/13) in non-mutant group in which 4 patients relapsed but all survived (1-year mortality 0%). Conclusions　The children with T-ALL had a high incidence of NOTCH1 mutations at various sites. In addition, the patients with NOTCH1 mutations had more severe disease at diagnosis, better short-term prognosis and poor outcome with salvage therapy after relapse.