A functional polymorphism in the paired basic amino acid-cleaving enzyme 4 gene confers osteoarthritis risk in a population of Eastern China.

Paired basic amino acid-cleaving enzyme 4 (PACE4), a proprotein convertase, is involved in the activation of aggrecanases (ADAMTS-4 and ADAMTS-5) in osteoarthritic and cytokine-stimulated cartilage. Activated aggrecanases cause aggrecan degradation and thus, contribute to osteoarthritis (OA). In this study, we investigated the association between PACE4 gene polymorphisms and OA risk. One single-nucleotide polymorphism (rs4965833) in the PACE4 gene was genotyped in 432 OA patients and 523 healthy controls using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Quantitative reverse transcription PCR (qRT-PCR) was used to determine the relative expression of PACE4 in blood samples from 90 OA patients (30 for each genotype). The relative expression level of PACE4 mRNA was higher in the GG genotype as compared to the AA/AG group. Moreover, the PACE4 rs4965833 polymorphism was associated with increased risk of OA, especially among individuals aged ≥55 years and with a body mass index ≥25. There was no significant association between the PACE4 rs4965833 polymorphism and clinical parameters of OA patients, such as erythrocyte sedimentation rate, C-reactive protein, Visual Analog Scale for pain and Lequesne's index. In conclusion, the rs4965833 polymorphism in the 3'-UTR of PACE4 is associated with OA susceptibility.