Fibrinogen Magdeburg I: a novel variant of human fibrinogen with an amino acid exchange in the fibrinopeptide A (Aalpha 9, Leu-->Pro).

Introduction: The exchange of Aalpha 16, Arg for Cys or His is the most common molecular defect in dysfibrinogenemia directly affecting the thrombin cleavage site involved in fibrinopeptide A (FPA) release. Other amino acid exchanges within the fibrinopeptide A have been only rarely reported.

Materials And Methods: In clinically asymptomatic dysfibrinogenemic patients with low functional plasma fibrinogen (Fg) levels and prolonged thrombin time but normal or slightly prolonged batroxobin (reptilase) time, mutation analysis was carried out by direct sequencing of the coding regions of the three fibrinogen genes.