Residual factor VII activity and different hemorrhagic phenotypes in CRM(+) factor VII deficiencies (Gly331Ser and Gly283Ser)

Autor: Mirko, Pinotti, Daniela, Etro, Debora, Bindini, Maria Luisa, Papa, Giuseppina, Rodorigo, Angiola, Rocino, Guglielmo, Mariani, Nicola, Ciavarella, Francesco, Bernardi, Marko, Pinotti, Dániela, Etro, Guglieuto, Mariani
Rok vydání: 2002
Předmět:
Zdroj: Blood. 99(4)
ISSN: 0006-4971
Popis: Two cross-reacting material–positive (CRM+) factor VII (FVII) mutations, associated with similar reductions in coagulant activity (2.5%) but with mild to asymptomatic (Gly331Ser, c184 [in chymotrypsin numbering]) or severe (Gly283Ser, c140) hemorrhagic phenotypes, were investigated. The affected glycines belong to structurally conserved regions in the c184 through c193 and c140s activation domain loops, respectively. The natural mutants 331Ser-FVII and 283Ser-FVII were expressed, and in addition 331Ala-FVII and 283Ala-FVII were expressed because 3 functional serine-proteases bear alanine at these positions. The 331Ser-FVII, present in several asymptomatic subjects, showed detectable factor Xa generation activity in patient plasma (0.7% ± 0.2%) and in reconstituted system with the recombinant molecules (2.7% ± 1.1%). The reduced activity of recombinant 283Ala-FVII (7.2% ± 2.2%) indicates that the full function of FVII requires glycine at this position, and the undetectable activity of 283Ser-FVII suggests that the oxydrile group of Ser283 participates in causing severe CRM+ deficiency. Furthermore, in a plasma system with limiting thromboplastin concentration, 283Ser-FVII inhibited wild-type FVIIa activity in a dose-dependent manner.
Databáze: OpenAIRE