Fibrinogen Geneva, a new case of A alpha 16 Arg----Cys dysfibrinogenaemia

A new congenital variant of fibrinogen, from which only half the normal amount of fibrinopeptide A can be released by thrombin, was found in three members of a family having no major bleeding or thrombotic tendency. Following carboxamidomethylation of the reduced fibrinogen chains, an abnormal peptide was cleaved by thrombin from the amino terminus of the A alpha-chain (A* alpha 1-19) and isolated by reversed phase high-performance liquid chromatography. Amino acid analysis indicated the presence of carboxymethyl cysteine in this A alpha-chain fragment which in normal fibrinogen is devoid of cysteine. We conclude that fibrinogen Geneva is another fibrinogen variant with the substitution A alpha 16 Arg----Cys.