GADD45A and osteoarthritis: We identified seven genes (ABI3BP, PRDX1, SQSTM1, GADD45A, HNRNPM, PTPRE and CALR) that showed evidence of both differential transcript usage and differential splicing between low- and high-osteoarthritis grade cartilage, suggesting that local splicing phenomena could underpin the observed different transcript usage for these genes.