Anti-GDF5 monoclonal antibody, clone FQS8454

Background: Variants in the growth differentiation factor 5 (GDF5) and in the double von Willebrand factor A (DVWA) have recently been reported to be associated with osteoarthritis (OA) in Asian populations. Objective: To assess the role of such variants in OA susceptibility in two independent UK samples of Caucasian origin. Methods: Polymorphisms rs11718863 and rs7639618 (DVWA) and rs143383 (GDF5) were genotyped in 999 patients with knee OA, 843 patients with hip OA and 1166 controls from two UK studies from Nottingham and Chingford. Results: In agreement with previous reports, the major allele at rs143383 (GDF5) was associated with a higher risk of knee OA in our samples (OR(MH) = 1.29, 95% CI 1.14 to 1.47 p = 8x10(-6)). Conversely, the major allele at the DVWA SNP rs7639618, which increased risk in Asians, was not associated with a risk of knee OA, (OR(MH) = 0.88, 95% CI 0.74 to 1.04; p = 0.12). A meta-analysis of Asian and UK knee OA data indicated highly significant heterogeneity (I(2) = 92%, Q = 48.5, p = 7x10(-10)) and no significant association with knee OA using a random effects meta-analysis (OR(DL) = 1.18, 95% CI 0.86 to 1.63; p = 0.309). Conclusions: These data confirm that the GDF5 variant is consistently associated with the risk of knee OA. Considerable ethnic variation in allele frequencies at the DVWA gene was found and no significant association was found in UK samples or by combining UK and Asian samples. The results suggest that the effect of DVWA amino acid changes on tubulin binding is unlikely to influence the risk of OA in Caucasians.

Objectives To identify genetic associations with hip osteoarthritis (HOA), we performed a meta-analysis of genome-wide association studies (GWAS) of HOA. Methods The GWAS meta-analysis included approximately 2.5 million imputed HapMap single nucleotide polymorphisms (SNPs). HOA cases and controls defined radiographically and by total hip replacement were selected from the Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF) (654 cases and 4697 controls, combined). Replication of genome-wide significant SNP associations (p <= 5x10(-8)) was examined in five studies (3243 cases and 6891 controls, combined). Functional studies were performed using in vitro models of chondrogenesis and osteogenesis. Results The A allele of rs788748, located 65 kb upstream of the IGFBP3 gene, was associated with lower HOA odds at the genome-wide significance level in the discovery stage (OR 0.71, p=2x10(-8)). The association replicated in five studies (OR 0.92, p=0.020), but the joint analysis of discovery and replication results was not genome-wide significant (p=1x10(-6)). In separate study populations, the rs788748 A allele was also associated with lower circulating IGFBP3 protein levels (p=4x10(-13)), suggesting that this SNP or a variant in linkage disequilibrium could be an IGFBP3 regulatory variant. Results from functional studies were consistent with association results. Chondrocyte hypertrophy, a deleterious event in OA pathogenesis, was largely prevented upon IGFBP3 knockdown in chondrocytes. Furthermore, IGFBP3 overexpression induced cartilage catabolism and osteogenic differentiation. Conclusions Results from GWAS and functional studies provided suggestive links between IGFBP3 and HOA.