Over a 36-month period, 46 consecutive Mexican mestizos with a clinical marker associated with a primary hypercoagulable state were prospectively assessed by searching for the sticky platelet syndrome (SPS), the activated protein C resistance (aPCR) phenotype, coagulation protein C activity and antigen, coagulation protein S, antithrombin III, plasminogen, tissue-type plasminogen activator activity, plasminogen activator inhibitor activity, plasminogen activator inhibitor type 1, IgG and IgM isotypes of antiphospholipid antibodies, homocysteine levels, the factor V gene Leiden, Cambridge, Hong Kong, and Liverpool mutations, the 677 CfiT mutation in the 5,10-methylenetetrahydrofolatereductase (MTHFR), and the G20210A polymorphism in the 3¢-untranslated region of the prothrombin gene. Of the 46 consecutive patients prospectively accrued in the study, only 12 (26%) were males, the median age being 38 years (range 10-63 years). In only four individuals (8%) could we not record any abnormality. In 5/42 patients with abnormal results (12%), a single abnormality was recorded, whereas in the remaining 37, two to five co-existing abnormalities were identified. We found 22 (48%) patients with the SPS, 11 (24%) with the aPCR phenotype, 5 (11%) with the factor V Leiden mutation, 7 (15%) with the prothrombin gene mutation, 29 (63%) with the MTHFR gene mutation, 11 (24%) with the factor V HR2 haplotype, 11 (24%) with antiphospholipid antibodies, 4 (9%) with PS deficiency, 6 (13%) with PC deficiency, one with the FV Hong Kong mutation, and one with AT-III deficiency. The results are consonant with the idea that most cases of thrombophilia in Mexico are multifactorial. Am.

In Mexican mestizo patients, the platelet GP IIIa PL(A1/A2) gene polymorphism does not lead to the SPS phenotype.

Activated protein C resistance (aPCR) phenotypes represent around 20% of the laboratory findings in Mexican Mestizos having suffered thrombosis and displaying clinical markers of thrombophilia. In a single institution for a 276-month period, 96 Mexican mestizos with a history of thrombosis and clinical markers of a primary thrombophilic state were prospectively studied to identify a thrombophilic condition. An abnormal aPCR phenotype was identified in 18 individuals. Evaluation of those with an abnormal aPCR phenotype, identified that 44% had factor V Leiden mutation, 22% increased levels of factor VIII, 16% anti-phospholipid antibodies and 6% a lupus anticoagulant. In the remaining 22%, the use of direct oral anticoagulants (DOACs) in the past period of 12-24 h was recorded. We found significant associations between abnormal aPCR phenotype and the factor V Leiden mutation ( = 0022), between abnormal aPCR phenotype and the use of DOACs ( = 0.006) and between antiphospholipid antibodies and lupus anticoagulant ( < 0.0001). These data are consonant with those observed in other populations and further identify that consideration be given to identifying whether individuals are being treated with the novel DOACs when conducting laboratory studies oriented to identify the etiology of thrombosis.