PHEXdb, a locus-specific database for mutations causing X-linked hypophosphatemia.
X-linked hypophosphatemia (XLH) is a dominant disorder of phosphate (Pi) homeostasis characterized by growth retardation, rachitic and osteomalacic bone disease, hypophosphatemia, and renal defects in Pi reabsorption and vitamin D metabolism. The gene responsible for XLH was identified by positional cloning and designated PHEX (formerly PEX) to depict a Phosphate regulating gene with homology to Endopeptidases on the X chromosome. To date, 131 mutations in the PHEX gene have been reported. We undertook to centralize information on mutations in the PHEX gene by establishing a database search tool, PHEXdb (http://data.mch.mcgill.ca/phexdb). This site is dedicated to the collection and distribution of information on PHEX mutations, and is accessible to the scientific community. PHEXdb provides a submission form to allow the addition of newly identified mutations in the PHEX gene. Users can search the database by mutation, phenotype, and authors who have published or submitted mutations. The PHEXdb home page includes links to information pages, which refer to recent publications on PHEX, XLH, and murine Hyp and Gy homologues, and to other web pages relevant to XLH. This resource will facilitate the identification of PHEX structure-function relationships and phenotype-genotype correlations.