title: [Fibrinogen Bern II: hereditary fibrinogen variant with amino acid substitution of arginine replaced by histidine in position 16 of the A alpha chain].
abstract: The number of described individuals with congenital dysfibrinogenemia continuously increases, but only a few fibrinogen variants have thus far been characterized with respect to their structural defect. Fibrinogen Bern II is a hereditary fibrinogen variant with impaired release of fibrinopeptide A (FPA) and a markedly prolonged coagulation time. It turned out that only half of the FPA was cleaved off at normal rate while the residual FPA was released much more slowly and incompletely, unless high thrombin concentrations were used. Amino acid analysis of normal and abnormal FPA revealed that the abnormal peptide, in contrast to the normal, contained histidine but hardly any arginine. It is therefore concluded that fibrinogen Bern II undergoes substitution of arginine in position 16 of the A alpha-chain by histidine. Thus, the structural alteration is identical with that of seven other recently described variants. The presence of 50% normal fibrinogen molecules provides the normal hemostasis in the heterozygous carriers of the Bern II-dysfibrinogenemia.
mesh_terms: D000347:Afibrinogenemia / Q000097:blood* / Q000453:epidemiology / Q000235:genetics; D000596:Amino Acids / Q000097:blood; D001120:Arginine; D055598:Chemical Phenomena; D002621:Chemistry; D005260:Female; D005340:Fibrinogen / Q000235:genetics*; D015241:Fibrinogens, Abnormal; D005344:Fibrinopeptide A / Q000378:metabolism; D014644:Genetic Variation; D006639:Histidine; D006801:Humans; D008297:Male; D013557:Switzerland; D013917:Thrombin / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D015241:Fibrinogens, Abnormal; C039581:fibrinogen Bern II; D005344:Fibrinopeptide A; D006639:Histidine; D005340:Fibrinogen; D001120:Arginine; D013917:Thrombin
vernacular_title: Fibrinogen Bern II: Fibrinogen-Erbvariante mit dem Aminosäurenaustausch Arginin leads to Histidin in Position 16 der A alpha-Kette.