Fibrinogen Hillsborough: a novel gammaGly309Asp dysfibrinogen with impaired clotting.
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Mullin JL, Brennan SO, Ganly PS, George PM
Fibrinogen Hillsborough: a novel gammaGly309Asp dysfibrinogen with impaired clotting.
Blood. 2002 May 15;99(10):3597-601.
- PubMed ID
- 11986213 [ View in PubMed]
- Abstract
We present a novel gamma-chain dysfibrinogen that was discovered in a 32-year-old asymptomatic man admitted to the hospital after a car accident. He presented with a low fibrinogen concentration, 0.5 mg/mL, and a prolonged thrombin clotting time, 58 seconds. Analysis of purified fibrinogen by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a gamma-chain variant with an apparently higher molecular weight. Isoelectric focusing (IEF) demonstrated an anodal shift in the banding pattern of the chains and electrospray ionization mass spectrometry (ESIMS) showed a 27-Da increase in the average mass of the unresolved variant and normal gamma chains. DNA sequence analysis showed a heterozygous mutation of GGC (Gly)-->GAC (Asp) at codon 309 of the gamma chain gene. This Gly--> Asp substitution was consistent with the charge change shown by IEF as well as the mass change identified by ESIMS. Functional analysis revealed that thrombin-catalyzed polymerization occurred with a longer lag time, lower rate of lateral aggregation, and similar final turbidity compared to normal and that factor XIII cross-linking was normal. The polymerization results suggest that residue gamma309 is necessary for proper alignment of fibrinogen molecules, specifically in protofibril formation and D:D interactions. gammaGly309 is highly conserved and x-ray structures support the conclusion that the lack of a side chain at this position helps facilitate the close contact between abutting gammaD domains of condensing fibrin monomers during polymerization.