Yadav Sneha, Shetty Shrimati, Kulkarni Bipin
National Institute of Immunohaematology (ICMR), KEM Hospital, Parel, Mumbai, India.
Transfusion. 2017 Nov;57(11):2712-2714. doi: 10.1111/trf.14279. Epub 2017 Aug 21.
Thrombotic thrombocytopenia purpura (TTP) is a rare and life-threatening thrombotic microangiopathy characterized by thrombocytopenia and microangiopathic hemolytic anemia. It is caused by deficiency of ADAMTS13 metalloprotease, which cleaves ultra-large von Willebrand factor into smaller functional units. TTP may be congenital or acquired, and the congenital form is caused by inherited mutations in the ADAMTS13 gene, leading to deficiency of protein or reduced protein activity.
We report a 5-year-old male patient who manifested with thrombocytopenia and microangiopathic hemolytic anemia at the age of 1 year.
ADAMTS13 activity in the patient was below 5%, and ADAMTS13 antibody was absent. Subsequent genetic analysis of the ADAMTS13 gene revealed a novel homozygous mutation (i.e., frameshift insertion mutation A237GfsX153 [c.708_709insG] in Exon 7 of ADAMTS13). Both parents were heterozygous for this mutation.
血栓性血小板减少性紫癜(TTP)是一种罕见的、危及生命的血栓性微血管病,其特征为血小板减少和微血管病性溶血性贫血。它由ADAMTS13金属蛋白酶缺乏引起,该酶可将超大的血管性血友病因子裂解为较小的功能单位。TTP可能是先天性的或后天获得性的,先天性形式由ADAMTS13基因的遗传性突变引起,导致蛋白质缺乏或蛋白质活性降低。
我们报告一名5岁男性患者,其在1岁时出现血小板减少和微血管病性溶血性贫血。
该患者的ADAMTS13活性低于5%,且不存在ADAMTS13抗体。随后对ADAMTS13基因进行的基因分析发现了一种新的纯合突变(即ADAMTS13第7外显子中的移码插入突变A237GfsX153 [c.708_709insG])。父母双方均为该突变的杂合子。