FGF23 and X-linked hypophosphatemic rickets: According to the mode of inheritance, thesesyndromes are classified in: X-linked hypophosphatemic rickets, autosomal dominantand recessive hypophosphatemic rickets1 and hypophosphatemic rickets with hypercalciuria, being dependent or not ofthe fibroblast growth factor 23 (FGF23), a bone-derived hormone.2