title: Inherited activated protein C resistance in a patient with familial primary antiphospholipid syndrome.
abstract: The mechanism of thrombophilia in patients with antiphospholipid antibodies (aPL) is not clearly understood. A number of contributing factors have been described, but more than one may be operative. It was recently found that aPL may cause the acquired activated protein C resistance phenotype, whereas in familial thrombophilia, activated protein C resistance frequently results from a point mutation in the factor V gene (replacing arginine 506 with a glutamine) that leads into the (R-506-Q), the so-called Leiden mutation, that produces a mutated factor V, resistant to the catalytic action of activated protein C, otherwise normal in its procoagulant properties. We describe one patient heterozygous for the activated protein C resistance genotype with a familial form of primary antiphospholipid syndrome, who had a nephew who died with this disease. In individuals who are heterozygous for the factor V Leiden mutation, the presence of aPL may cause further activated protein C resistance, resulting in increased thrombophilia.
authors.affiliation: Instituto nacional de la Nutrición Salvador Zubirán, México, DF, México.
authors.forename: D
authors.initials: D
authors.lastname: Alarcón-Segovia
authors.forename: G J
authors.initials: GJ
authors.lastname: Ruiz-Argüelles
authors.forename: J
authors.initials: J
authors.lastname: Garcés-Eisele
authors.forename: A
authors.initials: A
authors.lastname: Ruiz-Argüelles
mesh_terms: D000328:Adult; D016736:Antiphospholipid Syndrome / Q000235:genetics* / Q000503:physiopathology*; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D006801:Humans; D011486:Protein C / Q000502:physiology*
chemical_list: D011486:Protein C