Annual incidence, % (log scale).

Dotted gray area represents annual incidence of venous thrombosis in relatives without any defect (0.05%), with its 95% confidence interval (0.02%-0.08%).

*Excluding relatives with hereditary antithrombin, protein C, or protein S deficiency.

†One-hundred fifty-one single heterozygous prothrombin 20210G>A; annual incidence was 0.19% (95% CI, 0.08-0.38).

‡Three-hundred fifty-nine single heterozygous factor V Leiden; annual incidence was 0.22% (95% CI, 0.13-0.33).