TREAT-OA will address the need for better treatment and diagnostics for osteoarthritis (OA) - the most common cause of disability in Europe. Currently there are no drugs that can cure, reverse or halt the disease. Nor are there yet reliable clinical biochemical markers for diagnosis or prognosis which is an impediment to the management of OA, costs of therapeutic trials and the development of disease modifying drugs. TREAT-OA represents a large-scale collaborative, integrated, trans-disciplinary project utilising a resource of 28,000 OA phenotyped subjects with available genome-wide association scan data as well as leading basic science laboratories and technologies. This is the largest study of its kind that will address the generalisability and utility of genetic and biochemical risk factors throughout the EU. The key objectives of TREAT-OA are to: 1 Identify genes and biochemical markers consistently associated with risk and progression of OA 2 Use such genes to further our understanding of the molecular pathways involved in disease aetiology 3 Analyze pathways to identify targets for pharmacological intervention 4 Develop transgenic animal laboratory OA model systems . 5 Develop a panel of genetic and biochemical diagnostics for risk and progression of OA 6 Disseminate results from this extensive research at large and use results and technologies for training within the EU TREAT-OA will help develop European clinical and scientific excellence in the diagnosis and treatment of OA. The novel pathways in disease aetiology discovered will translate into novel drug targets and protein therapeutics for OA. The development of in vitro and in vivo assays will provide a comprehensive technology platform enabling the discovery and development of disease modifying drugs for OA. TREAT-OA will also make a major impact on the disease via a diagnostic panel of genes and biochemical markers for selecting severe cases and rapidly progressing individuals.