Thrombin activatable fibrinolysis inhibitor gene polymorphisms are associated with antigenic levels in the Asian-Indian population but may not be a risk for stroke.

Thrombin activatable fibrinolysis inhibitor [carboxypeptidase B2 (plasma), CPB2] is a basic carboxypeptidase, which inhibits fibrinolysis by cleaving the C-terminal lysine residues on plasmin-modified partially degraded fibrin. Plasma CPB2 concentrations have been reported to be under the control of numerous single nucleotide polymorphisms located in the regulatory and coding regions of the gene encoding CPB2 (CPB2). High functional CPB2 levels have been found to be associated with an increased risk for ischemic stroke. The present study investigated CPB2 antigen levels and associated CPB2 polymorphisms in an acute onset non-cardioembolic stroke population compared with an age- and sex-matched healthy control population. This is, to the best of our knowledge, the first such study done in an Asian Indian population. CPB2 antigen levels were significantly associated with the disease phenotype (P < 0.001) and with CPB2 polymorphisms (P < 0.001). The haplotypes generated on analysis of the genotypic data accounted for 21% of the natural variation in the CPB2 antigenic levels. However none of the haplotype combinations generated showed any association with disease phenotype and therefore could not explain for the difference in CPB2 antigen levels between cases and controls.