Association between plasminogen activator inhibitor gene polymorphisms and osteonecrosis of the femoral head susceptibility

This study aimed to analyze the correlation of the plasminogen activator inhibitor (PAI-1) gene polymorphisms (rs6092 and rs7242) with susceptibility of osteonecrosis of the femoral head (ONFH).This case-control study included 106 ONFH patients and 151 healthy controls. PAI-1 polymorphisms were genotyped by polymerase chain reaction (PCR) with direct sequencing. The genotype distribution of polymorphism in the control group was checked with the status of Hardy-Weinberg equilibrium (HWE). The χ test was applied to compare the genotypes of polymorphisms between the case and control groups. The association intensity between PAI-1 polymorphisms and ONFH risk was estimated by odds ratios (ORs) and 95% confidence intervals (95% CI). The linkage disequilibrium of PAI-1 polymorphisms was analyzed by Haploview.We found that the genotypes and alleles of PAI-1 rs6092 and rs7242 polymorphisms had no obvious association with the risk of ONFH (P >.05). But the strong linkage disequilibrium existed between rs6092 and rs7242 polymorphisms and haplotype G-T was significantly associated with the decreased risk of ONFH occurrence (OR = 0.666, 95%CI = 0.445-0.998).PAI-1 rs6092 and rs7242 polymorphisms are not associated with ONFH development, but haplotype G-T may be a protective factor of ONFH.