Fibrinogen Poissy II (γN361K): a novel dysfibrinogenemia associated with defective polymerization and peptide B release

A fibrinogen variant was identified in a pregnant patient with disseminated intravascular coagulation and abruptio placentae. This dysfibrinogen was also found in four asymptomatic members of the patient's family. Coagulation studies showed prolongation of both the thrombin and reptilase times, and discrepancy was noted between the levels of plasma fibrinogen as determined by a kinetic versus an immunological determination or light-scattering assay. Studies on purified fibrinogen revealed an impaired release of fibrinopeptide B by thrombin related to a delayed thrombin-induced fibrin polymerization. DNA sequencing revealed a heterozygous T <-- A point mutation in position 9373 of the gamma-chain gene (exon 9), which substituted a K for an N at position 361.