Genetic testing for thrombophilia mutations.

Venous thrombosis is a multicausal disease due to the interaction of genetic and environmental risk factors. Some of the recently discovered genetic risk factors, such as factor V Leiden and prothrombin G20210A mutations, are quite common in the population. Accordingly, laboratory investigation of thrombophilic disorders has expanded to incorporate molecular assays, which unlike functional assays, are unequivocal with no borderline values. When testing for these mutations, specific issues of patient management need to be addressed, such as the duration of anticoagulant therapy, risk stratification for primary or secondary prophylaxis, and family studies. Criteria used to select specific DNA methodologies will center on the issues of cost, automation, speed, reliability, and simplicity. A variety of molecular methods fulfill many but not all of these criteria, whereas the new, semiautomated methodologies of real-time polymerase chain reaction and DNA microarrays offer the potential for widespread application and utility in the future.