SP1 and brain ischemia: The abundance of the wild-type C allele is approximately 30% more than that of the mutant T allele, and the t-PA enhancer-7351C > T SNP diminishes the affinity of SP1 for this locus, a change that reduces the release of t-PA and thus affects the final infarct size in cerebral ischemia (Tjarnlund-Wolf et al., 2011).