Compound heterozygous protein C deficiency in a family with venous thrombosis: Identification and in vitro study of p.Asp297His and p.Val420Leu mutations.
Hereditary protein C deficiency (PCD) is an autosomal inherited disorder associated with high risk for venous thromboembolism (VTE). This study aimed to explore the functional consequences of two missense mutations, p.Asp297His and p.Val420Ile, responsible for type I/II PCD and recurrent deep vein thrombosis (DVT) in a Chinese family. The plasma protein C activities (PC:A) of the proband and his sister were reduced to 4% and 5% of normal activity. However, protein C antigen (PC:Ag) concentrations were not equally decreased, with levels of 90.5% and 88.7%, respectively. Two missense mutations p.Asp297His and p.Val420Leu were identified in the protein C gene (PROC). The PC:A and PC:Ag levels in heterozygous state for p.Asp297His were 66% and 64.8%, whereas in heterozygous state for p.Val420Leu, these levels were 67% and 145%, respectively. Wild type (WT) and two mutant PROC cDNA expression plasmids were constructed and transfected into HEK 293T cells. Western blot analysis revealed that both p.Asp297His and p.Val420Leu showed a normal intracellular protein level. The extracellular protein level and specific activity of p.Asp297His were equally reduced to 37.7 ± 4.3% and 22.1 ± 2.5%, respectively. Mutant p.Val420Leu showed a relatively higher PC:Ag level and undetectable PC:A. Immunofluorescence staining revealed that WT and p.Val420Leu proteins were largely co-localized with both the protein disulfide isomerase (PDI) and cis-Golgi Marker (GM130), while the PC p.Asp297His mutant protein was mainly co-localized with PDI and much less co-localized with GM130. The thrombosis symptom in this family was associated with the two missense mutations in the PROC gene.
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Hui
H
Liu
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Hua-Fang
HF
Wang
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China. Electronic address: lancet.tang@qq.com.
Liang
L
Tang
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Yan
Y
Yang
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Qing-Yun
QY
Wang
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Wei
W
Zeng
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Ying-Ying
YY
Wu
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Zhi-Peng
ZP
Cheng
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Bei
B
Hu
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China.
Tao
T
Guo
Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Collaborative Innovation Center of Hematology, Huazhong University of Science and Technology, China. Electronic address: dr_huyu@126.com.
Yu
Y
Hu
D044466:Asian People / Q000235:genetics; D005260:Female; D005455:Fluorescent Antibody Technique; D059647:Gene-Environment Interaction; D057809:HEK293 Cells; D006579:Heterozygote; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D011486:Protein C / Q000235:genetics* / Q000378:metabolism; D020151:Protein C Deficiency / Q000150:complications / Q000235:genetics*; D012307:Risk Factors; D020246:Venous Thrombosis / Q000188:drug therapy / Q000209:etiology / Q000235:genetics*; D014859:Warfarin / Q000494:pharmacology
D011486:Protein C; D014859:Warfarin
Mutation; Protein C deficiency; Venous thromboembolism (VTE)