Summary

A report on two homozygous twin girls affected by X linked hypophosphataemic rickets. They were examined due to short stature and genu varum of both tibias. They were treated with calcitriol and Joulie's solution, whereon it was observed that serum parathyroid hormone and phosphaturia decreased while phosphataemia increased. They underwent a tibial osteotomy (by means of the insertion of Kirchner needles) at 7.7 years of age for correction of genu varum and a normal consolidation was reached 1 month later. Nonetheless, height was percentile <1 after menarche, so both sisters asked for bone lengthening. Because of this, at 15 years of age femoral distraction was performed, but no bone callus was observed 14 months later. Consequently, they were treated with subcutaneous growth hormone, showing bone callus at 6 months. Finally, the external fixators were removed due to ossification in the lengthened segments.