Phosphate-regulating endopeptidase homolog 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.
A protein involved in regulating phosphate levels, inherited from the X chromosome and related to other enzymes, is coded by the PHEX gene in humans.