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Novel mutations in ADAMTS13 CUB domains cause abnormal pre-mRNA splicing and defective secretion of ADAMTS13 |
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| Authors: | Yizhi Jiang Dongping Huang Yuji Kondo Miao Jiang Zhenni Ma Lu Zhou Jian Su Xia Bai Changgeng Ruan Zhaoyue Wang Lijun Xia |
| Affiliation: | 1. Department of Hematology, The Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, China Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA;2. Department of Hematology, The Affiliated Yijishan Hospital of Wannan Medical College, Wuhu, China;3. Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA;4. Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China;5. Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China Department of Hematology, Affiliated Hospital of Nantong University, Nantong, China;6. Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China State Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, China;7. Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, Jiangsu Institute of Hematology, The First Affiliated Hospital of Soochow University, Suzhou, China |
| Abstract: | Hereditary thrombotic thrombocytopenic purpura (TTP) is an autosomal recessive thrombosis disorder, caused by loss-of-function mutations in ADAMTS13. Mutations in the CUB domains of ADAMTS13 are rare, and the exact mechanisms through which these mutations result in the development of TTP have not yet been fully elucidated. In this study, we identified two novel mutations in the CUB domains in a TTP family with an acceptor splice-site mutation (c.3569−1, G>A, intron 25) and a point missense mutation (c.3923, G>A, exon 28), resulting in a glycine to aspartic acid substitution (p.G1308D). In vitro splicing analysis revealed that the intronic mutation resulted in abnormal pre-mRNA splicing, and an in vitro expression assay revealed that the missense mutation significantly impaired ADAMTS13 secretion. Although both the patient and her brother displayed significantly reduced ADAMTS13 activity and increased levels of ultra-large VWF (ULVWF) multimers in plasma, only the female developed acute episodes of TTP. Our findings indicate the importance of the CUB domains for the protein stability and extracellular secretion of ADAMTS13. |
| Keywords: | ADAMTS13 genetic mutations thrombotic thrombocytopenic purpura von Willebrand factor |