GJA1 and osteoporosis: Cx43 has been gradually highlighted in recent research as an important regulator in the musculoskeletal system based on the discovery of its hemichannel and extracellular mechano-sensing mechanism, especially in bone development and joint diseases [6], such as rheumatoid arthritis (RA), osteoarthritis (OA), osteoporosis and occulodentodigital dysplasia (ODDD) [7-10].