Dysfibrinogen Kagoshima with the amino acid substitution gammaThr-314 to Ile: analyses of molecular abnormalities and thrombophilic nature of this abnormal molecule.
BACKGROUND
Emerging lines of evidence have suggested that certain dysfibrinogens present a significant risk of thrombosis.


METHODS
The thrombophilic nature of a new-type of dysfibrinogen Kagoshima identified in a 36-year-old female with deep vein thrombosis during the postpartum period was studied.


CONCLUSIONS
Based on the analyses of the patient fibrinogen and the fibrinogen genes, fibrinogen Kagoshima was shown to have the amino acid substitution of gammaThr-314 to Ile that resulted in impaired function and hypofibrinogenemia. Polymerization of fibrin monomers derived from patient fibrinogen was severely impaired with a partial correction in the presence of calcium ions, causing very low clottability and delayed cross-linking of patient fibrin catalyzed by activated factor XIII. Because of the low clottability, a large amount of soluble fibrin was formed upon thrombin treatment, resulting in an increase of thrombin in the soluble fraction. Additionally, tPA-mediated plasmin generation on fibrin was impaired and calcium-ion-dependent integrity of the gamma-chain D domain of Kagoshima fibrinogen was perturbed. The presence of many tapered-fiber ends inside the tangled fibrin networks, observed by scanning electron microscopy, suggested early termination of fibrin polymerization and the structural alteration.


CONCLUSIONS
These data suggest that fibrinogen Kagoshima is dysfunctional, giving rise to formation of fibrinolysis-resistant soluble fibrin polymers and entrance of soluble fibrin associating with thrombin to the circulation, partly accounting for the thrombophilic nature of the affected fibrinogen and fibrin molecules.
Niwa
Kazuki
K
Research Division of Cell and Molecular Medicine, Center for Molecular Medicine, Jichi Medical University, School of Medicine, Shimotsuke, Tochigi-ken 329-0498, Japan.
Mimuro
Jun
J
Miyata
Masaaki
M
Sugo
Teruko
T
Ohmori
Tsukasa
T
Madoiwa
Seiji
S
Tei
Chuwa
C
Sakata
Yoichi
Y
D000328:Adult; D019943:Amino Acid Substitution; D002118:Calcium / Q000737:chemistry; D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005337:Fibrin / Q000737:chemistry / Q000378:metabolism; D005340:Fibrinogen / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D015241:Fibrinogens, Abnormal / Q000032:analysis / Q000235:genetics*; D005341:Fibrinolysin / Q000737:chemistry; D006801:Humans; D007477:Ions / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016133:Polymerase Chain Reaction / Q000379:methods; D049590:Postpartum Period; D012995:Solubility; D013499:Surface Properties; D013917:Thrombin / Q000032:analysis; D019851:Thrombophilia / Q000175:diagnosis / Q000235:genetics*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000737:chemistry; D020246:Venous Thrombosis / Q000175:diagnosis / Q000235:genetics*
D015241:Fibrinogens, Abnormal; D007477:Ions; D005337:Fibrin; D005340:Fibrinogen; D013917:Thrombin; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D002118:Calcium