A NOVEL G A AND THE 4G/5G POLYMORPHISM WITHIN THE PROMOTER OF THE PLASMINOGEN-ACTIVATOR INHIBITOR-1 GENE IN PATIENTS WITH DEEP-VEIN THROMBOSIS/

Plasma plasminogen activator inhibitor-1 (PAI-1) level was observed to be associated with sequence variations at the PAI-1 locus. Therefore, PAI-1 gene promoter was screened for possibly new polymorphisms and t o investigate the contribution of these sequence variations to PAI-1 l evels in patients with deep vein thrombosis (DVT). DNA was isolated fr om blood of 83 consecutive unrelated patients (42+/-11 years old) and from 50 apparently healthy subjects of similar age and gender distribu tion. Six fragments covering DNA sequence-1523 base pairs (bp) upstrea m from the start of PAI-l gene transcription to +90 bp in the first ex on, were amplified by polymerase chain reaction and analyzed by single -strand conformation polymorphisms. Two polymorphisms were found: a pr eviously described 4G/5G deletion/insertion polymorphism 675 bp upstre am from the start of transcription and a novel G/A single base substit ution polymorphism further upstream at -844 bp. The two polymorphisms were in strong linkage disequilibrium. Significant differences between patients and controls were observed neither for the frequencies of th e 4G/5G alleles (0.60/0.40 and 0.59/0.41, respectively) nor for the fr equencies of the G/A alleles (0.33/0.67 and 0.41/0.59, respectively). The distribution of both polymorphisms was similar in idiopathic and s econdary DVT as well as in first and recurrent DVT. In patients associ ation between the 4G/5G genotypes and PAI activity was observed, with the highest values in the 4G/4G genotype (13.3 U/mL), median values in the 4G/5G genotype (9.8 U/mL) and the lowest values in the 5G/5G geno type (2.0 U/mL,). Despite the lack of association between the G/A geno types and plasma PAI-1 levels, ''electrophoretic mobility shift assay showed specific binding of a nuclear protein from human vascular endot helial cells extracts to both the G and the A variant, suggesting func tional importance of this never G/A polymorphism in regulating the exp ression of PAI-1 gene. Copyright (C) 1996 Elsevier Science Ltd