The genetic epidemiology of osteoarthritis.

PURPOSE OF REVIEW Osteoarthritis is the most common form of arthritis in the elderly and is influenced by both genetic and environmental risk factors. The scope of the present article is to offer an overview of recent developments in the genetic epidemiology of knee and hip osteoarthritis, with particular emphasis on published genomewide association studies (GWAS). RECENT FINDINGS Candidate gene studies and genomewide linkage studies have identified genes in the bone morphogenetic pathway (e.g. GDF5), the thyroid regulation pathway (DIO2) and apoptotic pathways as involved in genetic risk of large joint osteoarthritis. GWAS have reported structural genes (COL6A4), inflammation-related genes (PTGS2/PLA2G4A) and a locus on chr 7q22 (GPR22 and four other genes in the same linkage disequilibrium block) associated with osteoarthritis. SUMMARY Genetic studies have identified polymorphisms associated with osteoarthritis and related end-points. These include genes in signaling cascades involved in joint and bone biology, as well as genes in inflammatory pathways and a cluster of five genes in perfect linkage disequilibrium in the 7q22 region.