Abstract:

X-linked hypophosphatemic rickets (XLH) is a skeletal mineralization disorder characterized by hypophosphatemia, caused by pathogenic variants in the PHEX gene that lead to elevated levels of fibroblast growth factor 23 (FGF23), which in turn inhibits renal phosphate reabsorption. In children, XLH primarily manifests as lower limb-predominant skeletal deformities, growth retardation, short stature, bone and joint pain, and dental abscesses.The traditional treatment regimen for XLH consists of neutral phosphate combined with calcitriol. In 2018, burosumab was approved for the treatment of patients with XLH. Burosumab targets and binds to FGF23 to inhibit its activity, increases renal phosphate reabsorption, reduces urinary phosphate excretion, promotes intestinal phosphate absorption, elevates serum phosphorus levels, and improves skeletal mineralization function. It has gradually become the first-line treatment for XLH. However, XLH is currently incurable, and existing treatment regimens struggle to maintain normal serum phosphorus levels. Even after treatment, patients generally still have a shorter final height. Additionally, due to various issues including its high cost, burosumab is rarely used in China, and clinicians have limited understanding of the advances in the diagnosis and treatment of XLH. Currently, several drugs targeting FGFR, α-Klotho, and other molecules, that aim to inhibit the effects of elevated FGF23 levels, are under development and are expected to provide new therapeutic options for XLH. This article reviews the cutting-edge advances in the diagnosis and treatment of XLH to help readers grasp the current status and future directions of this field.

Key words: X-linked hypophatemia rickets, treatment progress, burosumab