They can be divided into two groups: vitamin D-dependent rickets which is caused by mutations either in enzymes involved in the vitamin D biosynthesis or vitamin D receptor (4), and hypophosphatemic rickets (HR) which is caused by impaired renal tubular phosphate reabsorption or transport due to genetic disorders associated with phosphatonins or phosphate co-transporters (5). Here, FGF23 is linked to rickets.