Study objectives: To investigate whether the FII
A20210 mutation is associated with isolated pulmonary
Design: Case-control study.
Setting: Five thrombosis centers in southern Italy.
Patients: Six hundred forty-seven consecutive referred
patients with objectively documented venous thrombosis and 1,329
Measurements and results: Medical
histories were collected. The G-to-A transition at nucleotide 1691
within the factor V gene (FV Leiden) and the G-to-A transition at
nucleotide position 20210 within the prothrombin gene locus (FII
A20210), levels of anticoagulant factors, and levels
of antiphospholipid antibodies were determined by standard techniques.
Patients with deep venous thrombosis (DVT) of the lower extremities
(n = 346) or with additional PEs (n = 175) showed similar
prevalences of FV Leiden mutation (24.3% and 16.6%, respectively) and
FII A20210 mutation (14.2% and 12.6%, respectively), and
similar deficiencies of natural anticoagulants (4.9% and 2.3%,
respectively). In both groups, the frequencies of FV Leiden and/or FII
A20210 mutation were higher than those observed among 1,329
apparently healthy control subjects (4.8% and 4.4%, respectively;
p < 0.0001). Among patients with isolated PE (n = 126),
prevalences of FV Leiden (7.1%) and FII A20210 mutation
(8.7%) were similar to those of control subjects. Inherited
thrombophilic abnormalities were less frequent among patients with PE
only (15.6%) than among those with DVT only (37.0%; p < 0.001) or
whose conditions were complicated by PE (28.0%; p = 0.020).
Adjusting for age and sex, FV Leiden mutation , FII A20210
mutation, or both mutations were associated with DVT with PE (FV Leiden
mutation: odds ratio [OR], 3.0; 95% confidence interval [CI], 1.6
to 5.5; FII A20210 mutation: OR, 2.6; 95% CI, 1.3 to 5.2;
and both mutations: OR, 82.1; 95% CI, 7.5 to 901.2) or without PE (FV
Leiden mutation: OR, 6.1; 95% CI, 4.0 to 9.3; FII A20210
mutation: OR, 2.8; 95% CI, 1.7 to 4.8; and both mutations: OR, 167.5;
95% CI, 21.6 to 1,297.7), but not with isolated PE (FV Leiden
mutation: OR, 1.2; 95% CI, 0.5 to 2.8; FII A20210
mutation: OR, 1.2; 95% CI, 0.5 to 3.1; and both mutations: OR, 22.1;
95% CI, 1.3 to 370.2).
A20210 mutation is associated with DVT in the lower
extremities alone or when complicated by PE, but it is not associated
with isolated PE.