Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree
Background: Congenital coagulation factor X (FX) deficiency is a rare bleeding disorder with an incidence of one in one million caused by mutations in the FX-coding gene(F10), leading to abnormal coagulation activity and a tendency for severe hemorrhage. Therefore, identifying mutations in FX is imp...
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MDPI AG
2021-09-01
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| Series: | Genes |
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| Online Access: | https://www.mdpi.com/2073-4425/12/10/1521 |
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| author | Yuanzheng Feng Jiewen Ma Liang V Tang Wenyi Lin Yanyi Tao Zhipeng Cheng Yu Hu |
| author_facet | Yuanzheng Feng Jiewen Ma Liang V Tang Wenyi Lin Yanyi Tao Zhipeng Cheng Yu Hu |
| author_sort | Yuanzheng Feng |
| collection | DOAJ |
| description | Background: Congenital coagulation factor X (FX) deficiency is a rare bleeding disorder with an incidence of one in one million caused by mutations in the FX-coding gene(F10), leading to abnormal coagulation activity and a tendency for severe hemorrhage. Therefore, identifying mutations in FX is important for diagnosing congenital FX deficiency. Results: Genetic analysis of the proband identified two single-base substitutions: c.794T > C: p.Ile265Thr and c.865 + 5G > A: IVS7 + 5G > A. His FX activity and antigen levels were < 1% and 49.7%, respectively; aPTT and PT were prolonged to 65.3 and 80.5 s, respectively. Bioinformatics analysis predicted the two novel variants to be pathogenic. In-vitro expression study of the missense mutation c.794T > C: p.Ile265Thr showed normal synthesis and secretion. Activation of FXs by RVV, FVII/TF, and FVIII/FIX all showed no obvious difference between the variant and the reference. However, clotting activity by PT and aPTT assays and activity of thrombin generation in a TGA assay all indicated reduced activity of the mutant FX-Ile265Thr compared to FX-WT. Minigene assay showed a normal splicing mode c.865 + 5G > A: IVS7 + 5G > A, which is inconsistent with clinical phenotype. Conclusions: The heterozygous variants c.794T > C: p.Ile265Thr or c.865 + 5G > A: IVS7 + 5G > A indicate mild FX deficiency, but the compound heterozygous mutation of the two causes severe congenital FX deficiency. Genetic analysis of these two mutations may help characterize the bleeding tendency and confirm congenital FX deficiency. In-vitro expression and functional study showed that the low activity of the mutant FX-Ile265Thr is caused by decrease in its enzyme activity rather than self-activation. The minigene assay help us explore possible mechanisms of the splicing mutation. However, more in-depth mechanism research is needed in the future. |
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| language | English |
| last_indexed | 2024-03-10T06:32:20Z |
| publishDate | 2021-09-01 |
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| series | Genes |
| spelling | doaj.art-02b5b45a2e914fe7aa0f3cbb582ea4542023-11-22T18:21:15ZengMDPI AGGenes2073-44252021-09-011210152110.3390/genes12101521Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese PedigreeYuanzheng Feng0Jiewen Ma1Liang V Tang2Wenyi Lin3Yanyi Tao4Zhipeng Cheng5Yu Hu6Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaInstitute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefang Avenue, Wuhan 430022, ChinaBackground: Congenital coagulation factor X (FX) deficiency is a rare bleeding disorder with an incidence of one in one million caused by mutations in the FX-coding gene(F10), leading to abnormal coagulation activity and a tendency for severe hemorrhage. Therefore, identifying mutations in FX is important for diagnosing congenital FX deficiency. Results: Genetic analysis of the proband identified two single-base substitutions: c.794T > C: p.Ile265Thr and c.865 + 5G > A: IVS7 + 5G > A. His FX activity and antigen levels were < 1% and 49.7%, respectively; aPTT and PT were prolonged to 65.3 and 80.5 s, respectively. Bioinformatics analysis predicted the two novel variants to be pathogenic. In-vitro expression study of the missense mutation c.794T > C: p.Ile265Thr showed normal synthesis and secretion. Activation of FXs by RVV, FVII/TF, and FVIII/FIX all showed no obvious difference between the variant and the reference. However, clotting activity by PT and aPTT assays and activity of thrombin generation in a TGA assay all indicated reduced activity of the mutant FX-Ile265Thr compared to FX-WT. Minigene assay showed a normal splicing mode c.865 + 5G > A: IVS7 + 5G > A, which is inconsistent with clinical phenotype. Conclusions: The heterozygous variants c.794T > C: p.Ile265Thr or c.865 + 5G > A: IVS7 + 5G > A indicate mild FX deficiency, but the compound heterozygous mutation of the two causes severe congenital FX deficiency. Genetic analysis of these two mutations may help characterize the bleeding tendency and confirm congenital FX deficiency. In-vitro expression and functional study showed that the low activity of the mutant FX-Ile265Thr is caused by decrease in its enzyme activity rather than self-activation. The minigene assay help us explore possible mechanisms of the splicing mutation. However, more in-depth mechanism research is needed in the future.https://www.mdpi.com/2073-4425/12/10/1521factor Xdeficiencycompound heterozygous mutationscoagulationbleeding |
| spellingShingle | Yuanzheng Feng Jiewen Ma Liang V Tang Wenyi Lin Yanyi Tao Zhipeng Cheng Yu Hu Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree Genes factor X deficiency compound heterozygous mutations coagulation bleeding |
| title | Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree |
| title_full | Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree |
| title_fullStr | Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree |
| title_full_unstemmed | Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree |
| title_short | Characterization of a Missense Mutation in the Catalytic Domain and a Splicing Mutation of Coagulation Factor X Compound Heterozygous in a Chinese Pedigree |
| title_sort | characterization of a missense mutation in the catalytic domain and a splicing mutation of coagulation factor x compound heterozygous in a chinese pedigree |
| topic | factor X deficiency compound heterozygous mutations coagulation bleeding |
| url | https://www.mdpi.com/2073-4425/12/10/1521 |
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