Preface: It has been an exciting year for life science in the skeletal research field with several seminal findings ranging from basic science and genetics to novel successful treatments. The powerful technology of cell-tracing is developing and is bringing new understanding to the identity and behaviour of skeletal stem cells. Two reports in Nature have identified the perichondrial stem cell pool that contribute bone cells to the periosteum as well as the behaviour of the growth plate stem cells in the resting zone.
For a number of years, the development of an FGF23 antibody (Burosumab) that binds and neutralises the excess FGF23 in XLH and the development of a bone-targeted alkaline phosphatase replacement therapy (Asfotase Alfa) for hypophosphatasia have been in focus. We now highlight: the first phase 3 study of FGF23 antibody treatment in children with XLH, demonstrating superiority over conventional treatment; outcomes of a single-arm 7-year phase 2 extension trial of Asfotase alfa for infants and children with hypophosphatasia; and additional preclinical data of ENPP1 enzyme replacement therapy, an emerging therapy for generalized arterial calcification of infancy. In addition to these areas of progress, the chapter reports several exciting findings including new genes in rare skeletal disorders, cartilage-targeted IGF1 therapy, Humanin as a potential treatment to prevent glucocorticoid-induced bone growth impairment and more.