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Aliases PHEX, HPDR, HPDR1, HYP, HYP1, LXHR, PEX, XLH, phosphate regulating endopeptidase homolog, X-linked
External IDs OMIM: 300550 MGI: 107489 HomoloGene: 37310 GeneCards: PHEX
Genetically Related Diseases
Gilles de la Tourette syndrome, smallpox[1]
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr X: 22.03 – 22.25 Mb Chr X: 157.16 – 157.42 Mb
PubMed search [2] [3]
View/Edit Human View/Edit Mouse

Phosphate-regulating neutral endopeptidase, X-linked also known as phosphate-regulating gene with homologies to endopeptidases on the X chromosome or metalloendopeptidase homolog PEX is an enzyme that in humans is encoded by the PHEX gene.[4][5] This gene contains 18 exons and is located on the X chromosome.


The protein encoded by this gene is a transmembrane endopeptidase that belongs to the type II integral membrane zinc-dependent endopeptidase family. The protein is thought to be involved in bone and dentin mineralization and renal phosphate reabsorption.[6] The bone and dentin protein osteopontin (OPN) which inhibits mineralization in the skeleton and in teeth is a substrate for PHEX.[7] In the absence of functional PHEX in the mouse model (Hyp) of X-linked hypophosphatemia, in addition to renal phosphate wasting, osteopontin and osteopontin fragments accumulate in bone and may contribute to the osteomalacia characteristic of XLH/HYP.[7] XLH patients have soft and deformed skeletons and soft teeth that easily become infected.

Clinical significance[edit]

Mutation of PHEX leads to X-linked hypophosphatemia.[4]


  1. ^ "Diseases that are genetically associated with PHEX view/edit references on wikidata". 
  2. ^ "Human PubMed Reference:". 
  3. ^ "Mouse PubMed Reference:". 
  4. ^ a b "A gene (PEX) with homologies to endopeptidases is mutated in patients with X-linked hypophosphatemic rickets (XLH/HYP). The HYP Consortium". Nat. Genet. 11 (2): 130–6. October 1995. doi:10.1038/ng1095-130. PMID 7550339. 
  5. ^ Grieff M, Mumm S, Waeltz P, Mazzarella R, Whyte MP, Thakker RV, Schlessinger D (February 1997). "Expression and cloning of the human X-linked hypophosphatemia gene cDNA". Biochem. Biophys. Res. Commun. 231 (3): 635–9. doi:10.1006/bbrc.1997.6153. PMID 9070861. 
  6. ^ "Entrez Gene: phosphate regulating endopeptidase homolog". 
  7. ^ a b Barros, NMT; et al. (2013). "Proteolytic processing of osteopontin by PHEX and accumulation of osteopontin fragments in Hyp mouse bone, the murine model of X-linked hypophosphatemia". Journal of Bone and Mineral Research. 28 (3): 688–699. doi:10.1002/jbmr.1766. PMID 22991293. 

This article incorporates text from the United States National Library of Medicine, which is in the public domain.