Molecular mechanisms of antithrombin deficiency in two Chinese families

Rong-Fu Zhou; Qi-Hua Fu; Wen-Bin Wang; Shuang Xie; Jin Dai; Qiu-Lan Ding; Xue-Feng Wang; Hong-Li Wang; Zhen-Yi Wang

doi:10.1160/TH05-06-0450

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2005; 94(06): 1172-1176
DOI: 10.1160/TH05-06-0450

Blood Coagulation, Fibrinolysis and Cellular Haemostasis

Schattauer GmbH

Molecular mechanisms of antithrombin deficiency in two Chinese families

One novel and one recurrent point mutation in the antithrombin gene causing venous thrombosis

Rong-Fu Zhou^*

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

²Division of Hematology, Nanjing Drum Tower Hospital, Nanjing University, Nanjing Jiangsu Province, People’s Republic of China

,

Qi-Hua Fu^*

³Institute of Transfusion Medicine, Blood Center of Zhejiang Province, Hangzhou, Zhejiang, People’s Republic of China

,

Wen-Bin Wang

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Shuang Xie

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Jin Dai

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Qiu-Lan Ding

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Xue-Feng Wang

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Hong-Li Wang

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

,

Zhen-Yi Wang

¹Division of Thrombosis and Hemostasis, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Second Medical University, Shanghai, People’s Republic of China

› Author Affiliations

Abstract

Summary

We investigated the molecular mechanisms responsible for type I congenital antithrombin (AT) deficiency in two unrelated Chinese pedigrees manifesting multiple site venous thrombosis. Phenotype analysis showed both probands had almost 50% of normal AT levels. Direct sequencing of amplified DNA revealed 2757C>T in proband 1 and 13328G>A in proband 2, predicting a heterozygous Thr98Ile (T98I) and Ala404Thr (A404T), respectively. No proband had 20210A allele or factorV Leiden mutation. Transient expression of complementary DNA coding for the mutations in COS-7 cells showed impaired secretion of the mutant molecules. Real-time quantitative PCR indicated that the mutant AT mRNA was transcribed at a similar or even higher level as that of wild-type (wt). Pulse-chase labeling studies suggested both AT variants did not accumulate, but degraded intracellularly. Immunohistochemical staining of the transfected cells revealed that CHO cells expressing the AT-I98 mutant were stained diffusely without perinuclear enhancement and cells expressing AT-T404 mutant mainly in the whole cytoplasm with weaker perinuclear enhancement. We conclude that the impaired secretion of the mutant AT molecules, due to intracellular degradation, is the molecular pathogenesis of AT deficiency caused by T98I and A404T mutation for the two families, respectively.

Keywords

Antithrombin deficiency - gene mutation - venous thrombosis

Full Text

References

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