A group of 102 Mexican Mestizo patients with appropriate clinical features suggestive of primary thrombophilia was prospectively studied. Thirty-nine percent of them had activated protein C resistance, but only four patients displayed the factor V Leiden mutation. Five percent of the individuals were found to be protein C deficient, whereas 2% had protein S deficiency. No cases of abnormalities in antithrombin III, plasminogen, tissuetype plasminogen activator or plasminogen activator inhibitor were found. The low prevalence of the activated protein C resistance genotype, probably stemming from the genetic admixture of the Mexican Mestizo group is noteworthy. Am. J. Hematol. 60:1-5, 1999.

A group of 102 Mexican Mestizo patients with appropriate clinical features suggestive of primary thrombophilia was prospectively studied. Thirty-nine percent of them had activated protein C resistance, but only four patients displayed the factor V Leiden mutation. Five percent of the individuals were found to be protein C deficient, whereas 2% had protein S deficiency. No cases of abnormalities in antithrombin III, plasminogen, tissuetype plasminogen activator or plasminogen activator inhibitor were found. The low prevalence of the activated protein C resistance genotype, probably stemming from the genetic admixture of the Mexican Mestizo group is noteworthy. Am. J. Hematol. 60:1-5, 1999.