clots ). It is a serine protease inhibitor (serpin) protein (SERPINE1). The PLANH1 gene is located on the seventh chromosome (7q21.3-q22). There is a common polymorphism known as 4G/5G [rs1799899] in the promoter region. The 5G allele is slightly less transcriptionally active than the 4G . PAI-1 is mainly produced by