Thrombotic Risks: A Clarification

Rogier M. Bertina has written a clear, timely, and authoritative review of factor V Leiden and other coagulation factor mutations affecting thrombotic risk (1).I was confused by the fact that the sum of genetic defects in inherited thrombophilia plus the cases with unknown cause add up to 109.7% (Table 1 of reference 1 ). This could occur due to multiple defects in individual patients. However, it might just be a typographical error, where the unknown cases are 20% rather than 30%.I would … aAddress correspondence to: fax 31-526-6755; e-mail Bertina{at}rullf2.leidenuniv.nl