3岁男孩反复血小板减少伴溶血性贫血

患儿男，3岁8个月，反复血小板减少伴溶血性贫血3年余，体检无肝脾、淋巴结肿大，无手指畸形。实验室结果示直接抗人球蛋白试验阴性，凝血功能正常，胆红素、乳酸脱氢酶及网织红细胞升高，完善血管性血友病因子裂解酶（von Willebrand factor-cleaving protease，ADAMTS13）活性检测示极度缺乏，ADAMTS13活性抑制性抗体阴性，二代测序发现ADAMTS13基因存在复合杂合突变，最终确诊为先天性血栓性血小板减少性紫癜。该病易误诊为Evans综合征，临床诊断较困难，该患儿自出生时即起病，但历时3年才得以确诊，因此，当患儿出生时有黄疸、反复血小板减少伴溶血性贫血、直接抗人球蛋白试验阴性时，需警惕先天性血栓性血小板减少性紫癜，尽快完善ADAMTS13活性及抑制性抗体检测来协助诊断、指导治疗，必要时完善基因检测以确诊。

Recurrent thrombocytopenia with hemolytic anemia in a boy aged 3 years

A boy, aged 3 years and 8 months, had recurrent thrombocytopenia with hemolytic anemia for more than 3 years. The physical examination showed no enlargement of the liver, spleen, and lymph nodes or finger deformities. Laboratory results showed a negative result of the direct antiglobulin test, normal coagulation function, and increases in bilirubin, lactate dehydrogenase and reticulocytes. The results of von Willebrand factor-cleaving protease ADAMTS13 activity assay showed extreme deficiency, and antibody assay showed negative ADAMTS13 inhibitory autoantibodies. Next-generation sequence showed compound heterozygous mutation in the ADAMTS13 gene. The boy was diagnosed with congenital thrombotic thrombocytopenic purpura. This disease may be easily misdiagnosed as Evans syndrome and is difficult to diagnose in clinical practice. The child had developed the disease since birth, but it took 3 years to make a confirmed diagnosis. Therefore, congenital thrombotic thrombocytopenic purpura should be considered for children with jaundice at birth, recurrent thrombocytopenia with hemolytic anemia, and negative results of the direct antiglobulin test. The detection of ADAMTS13 activity and ADAMTS13 inhibitory autoantibodies should be performed as soon as possible for a definite diagnosis, and gene detection should be performed to make a confirmed diagnosis when necessary.