A novel variant fibrinogen, deletion of Bbeta111Ser in coiled-coil region, affecting fibrin lateral aggregation.
BACKGROUND
Functional fibrinogen concentration of a male infant showed <0.50 g/l and we speculated this patient as a dysfibrinogenemia or hypofibrinogenemia.


METHODS
We analyzed propositus and his parent by DNA sequencing and by thrombin-catalyzed fibrin polymerization for purified plasma fibrinogen.


RESULTS
Although functional fibrinogen determinations based on Clauss method showed the marked discrepancy of values among 3 sets of reagent and analyzer, we found a novel heterozygous variant fibrinogen, Kyoto IV, caused by 3-bp deletion in Bbeta-chain gene corresponding to the deletion of 111Ser located in coiled-coil region. We suggested that the discrepancy of fibrinogen values among 3 assays was caused by the difference in NaCl concentration in reagents for determination and analyzed the polymerization under the conditions of various NaCl concentrations. Although under normal physiological conditions Kyoto IV fibrinogen augmented the polymerization as compared with normal control, in 0.21 mol/l NaCl Kyoto IV fibrinogen showed abruptly impaired polymerization curve compared with normal control.


CONCLUSIONS
Variant fibrinogen, BbetaDelta111Ser, showed augmented lateral aggregation under normal physiological conditions and the residue located in coiled-coil region, Bbeta111Ser, plays an important role in the lateral aggregation.
Okumura
Nobuo
N
Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University, Japan. nobuoku@gipac.shinshu-u.ac.jp
Terasawa
Fumiko
F
Hirota-Kawadobora
Masako
M
Yamauchi
Kazuyoshi
K
Nakanishi
Kayoko
K
Shiga
Shuichi
S
Ichiyama
Satoshi
S
Saito
Megumu
M
Kawai
Masahiko
M
Nakahata
Tatsutoshi
T
D000328:Adult; D001483:Base Sequence; D005260:Female; D005337:Fibrin / Q000648:ultrastructure; D005340:Fibrinogen / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D008297:Male; D008855:Microscopy, Electron, Scanning; D016133:Polymerase Chain Reaction; D011487:Protein Conformation
D005337:Fibrin; D005340:Fibrinogen