The Parathyroid Hormone 1 Receptor (PTH1R) gene codes for a member of the G-protein coupled receptor family 2, which is a receptor for both parathyroid hormone and parathyroid-like hormone. The protein functions to regulate calcium ion homeostasis through activation of adenylate cyclase as well as a phosphatidylinositol-calcium second messenger system. The signal transduction cascade associated with the receptor stimulates osteoclasts to increase the resorption rate of calcium. In addition, it also mediates the paracrine activities of parathyroid-like hormone, which is involved in the process of endochondral bone development and epithelial-mesenchymal interactions during teeth and mammary gland formation. The gene is primarily expressed in the bones and kidneys.
Mutations in the PTHR1 gene have been associated with a number of disorders. These include Blomstrand Type chondrodysplasia, a skeletal dysplasia with advancement of bone maturation, Jansen metaphyseal chondrodysplasia, a form of short-limb dwarfism characterized by a retarded differentiation of chondrocytes, Ollier disease, characterized by multiple cartilage tumors and skeletal deformity, Eiken syndrome, a form of skeletal dysplasia characterized by multiple epiphyseal dysplasia and extremely retarded ossification, and Primary Failure of Tooth Eruption (PFE).