OBJECTIVE: Antiphospholipid syndrome (APS) may have a familial association. This familial tendency could be genetically determined.

METHODS: In this study we analyzed family consisted of 7 members, with three affected members: father and two suns. The diagnosis was established by clinical signs, imaging methods, presence of anti cardiolipin and anti β² glicoprotein I antibodies, homocysteine levels, coagulation factors as well as protein C, protein S, antithrombin III deficiencies and APC resistance. DNA polymorphisms in genes encoding for factor V (G1691A), prothrombin (G20210A), MTHFR (C677T and A1298C) were analyzed by PCR/RFLPS method. Plasma Hcy was measured by HPLC method.

RESULTS and CONCLUSION: Father and two suns had pulmonary embolism. Nobody have positive ANA, dsDNA and RF. The values of anti cardiolipin anti β² glicoprotein I antibodies were border line positive. Hcy levels and platelet number were within normal range. All members of family had low value of factor V, and father and both of suns also had low factor II, VII and X. Father and his suns had low protein C and S, but they are on anticoagulant therapy.

Low prevalence of C677T, A1298C, G1691A and G20210A polymorphisms suggests that these genetic alterations are not prominent risk factors in this family. In the context of biochemical and clinical phenotypes further investigations will include analyses of new DNA polymorphisms, which could be associated with family disease.