
Hypophosphatemic rickets is a type of hereditary rickets characterized by persistent hypophosphatemia and hyperphosphaturia. The most predominant type is inherited in an x-linked fashion and caused by mutation in the gene encoding the phosphateregulating endopeptidase homolog X-linked (PHEX) which causes deficient mineralization of structures such as bones and teeth. The pathophysiological defect in XLH is speculated to cause an increase in a circulating phosphate regulating hormone termed phosphatonin (fibroblast growth factor 23 is the primary phosphatonin) which leads to parathyroid hormone-independent phosphaturia. We here describe a patient 30 years old male with genu varum, which presented with fragility fracture in lower limb and diagnosed as X-linked dominant hypophosphatemia (XLH) with osteomalacia after thorough history, examination, radiological and various blood tests.