X-linked hypophosphatemic rickets/osteomalacia (XLH, OMIM 307800) is an inherited metabolic disease resulting from inactivating mutations in the phosphate-regulating endopeptidase homologue, X-linked (PHEX) gene, with an incidence of approximately 1 in 20 000 births [1, 2]. Here, PHEX is linked to X-linked hypophosphatemia.