Electrospray ionisation mass spectrometry facilitates detection of fibrinogen (Bbeta 14 Arg --> Cys) mutation in a family with thrombosis.
We report the first direct detection of a fibrinogen mutation by electrospray ionisation mass spectrometry. The propositus, from a family with a history of thrombosis, came to attention after a pulmonary embolism subsequent to a spontaneous abortion. Prolonged thrombin (41 s) and reptilase times (26 s) together with an impairment of fibrinopeptide B release suggested a mutation at the thrombin cleavage site of the Bbeta chain. Direct mass analysis of purified fibrin chains from a thrombin induced clot showed that 50% of the Bbeta chains remained uncleaved. The measured mass of the mono sialo isoform of this uncleaved chain was 54150 Da, compared to a value of 54198 Da for normal Bbeta chains. This decrease of 48 Da in the intact protein is indicative of either a Bbeta 14 Arg to Cys, or Arg to Leu substitution. Heterozygosity for the Bbeta 14 Arg --> Cys mutation was verified by PCR amplification and DNA sequence analysis.
Brennan
S O
SO
Canterbury Health Laboratory, Christchurch Hospital, New Zealand.
Hammonds
B
B
Spearing
R
R
George
P M
PM
D000328:Adult; D019943:Amino Acid Substitution; D001120:Arginine / Q000235:genetics; D002384:Catalysis; D003545:Cysteine / Q000235:genetics; D005192:Family Health; D005260:Female; D005337:Fibrin / Q000032:analysis / Q000737:chemistry; D005340:Fibrinogen / Q000032:analysis / Q000737:chemistry; D005344:Fibrinopeptide A / Q000378:metabolism; D005345:Fibrinopeptide B / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D006023:Glycoproteins / Q000032:analysis; D006579:Heterozygote; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics / Q000502:physiology; D017354:Point Mutation / Q000235:genetics / Q000502:physiology; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis; D013917:Thrombin / Q000737:chemistry; D013927:Thrombosis / Q000235:genetics*
D006023:Glycoproteins; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; D005337:Fibrin; D005340:Fibrinogen; D001120:Arginine; D013917:Thrombin; D003545:Cysteine