Decreased PITX1 mRNA expression in primary human articular chondrocytes, reduced PITX1 protein in histological sections of human osteoarthritic cartilage, and increased subchondral bone thickening in preliminary studies of ageing Pitx1+/− mice are all consistent with an important role for PITX1 in osteoarthritis pathogenesis95. This evidence concerns the gene PITX1 and osteoarthritis.