The most common heritable disorder of renal phosphate wasting, X-linked 
hypophosphataemia (XLH), was discovered to be caused by inactivating mutations 
in the phosphate regulating gene with homology to endopeptidases on the 
X-chromosome (PHEX) gene in 1995. Although the exact molecular mechanisms by 
which PHEX mutations cause disturbed phosphate handling in XLH remain unknown, 
focus for novel therapies has more recently been based upon the finding that the 
bone-produced phosphaturic hormone fibroblast growth factor-23 is elevated in 
XLH patient plasma. Previous treatment strategies for XLH were based upon 
phosphate repletion plus active vitamin D analogues, which are difficult to 
manage, fail to address the primary pathogenesis of the disease, and can have 
deleterious side effects. A novel therapy for XLH directly targeting fibroblast 
growth factor-23 via a humanized monoclonal antibody (burosumab-twza/CRYSVITA, 
henceforth referred to just as burosumab) has emerged as an effective, and 
recently approved, pharmacological treatment for both children and adults. This 
review will provide an overview of the clinical manifestations of XLH, the 
molecular pathophysiology, and summarize its current treatment.