Hereditary protein C deficiency caused by compound heterozygous mutants in two independent Chinese families.
We report two compound heterozygous mutants that caused severe type I protein C (PC) deficiency in two independent Chinese families.PC antigen was determined by enzyme-linked immunosorbent assay (ELISA), and PC activity was measured by chromogenic assay. Genetic mutations were screened with polymerase chain reaction (PCR) followed by direct sequencing. PC mutants were transiently expressed in COS-7 cells for the evaluation of PC secretory activity and function. The subcellular location was visualised by immunofluorescence assay. The structural analysis of mutation was performed as well.Compound heterozygous mutations of Arg178Trp and Asp255His with reduced PC activity and antigen levels were identified in Proband 1, a 28-year-old male with deep vein thrombosis (DVT) and pulmonary embolism. The other mutations of Leu-34Pro and Thr295Ile with reduced PC activity and antigen levels were identified in Proband 2, a 19-year-old male with DVT. The PC activities with Arg178Trp, Asp255His, Leu-34Pro and Thr295Ile mutations decreased significantly. Immunofluorescence assay demonstrated that only trace amount of PC with novel Thr295Ile mutation was transported to the Golgi apparatus. Subsequent structural analysis indicated severe impairments of intracellular folding and secretion.The two rare compound heterozygous mutations could cause type I PC deficiency via impairment of secretory activity of PC.
1Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 2Department of Laboratory Medicine, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 3Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China *these authors contributed equally to this study.
Ying-Ting
YT
Wu
Fei
F
Yue
Min
M
Wang
Ye-Ling
YL
Lu
Jing
J
Dai
Qiu-Lan
QL
Ding
Hong-Li
HL
Wang
Hui-Fen
HF
Chen
Xue-Feng
XF
Wang
D000328:Adult; D000818:Animals; D044466:Asian People / Q000235:genetics*; D019556:COS Cells; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D020151:Protein C Deficiency / Q000235:genetics*; D011655:Pulmonary Embolism / Q000235:genetics; D020246:Venous Thrombosis / Q000235:genetics; D055815:Young Adult