X-linked hypophosphataemia (XLH) is the most common genetic cause of phosphate deficiency. It is a rare disease manifested by rickets, osteomalacia, odontomalacia, disproportionately short stature and some other typical complications.
We present a case report of two siblings with a familial occurrence of XLH, which was diagnosed in both between 2 - 3 years of age on the basis of a typical clinical laboratory and radiological picture. Despite early initiation of conventional treatment, the effect has not been sufficient due to poor tolerance of phosphate preparations and non-adherence to treatment.