EXPRESSION AND CLONING OF THE HUMAN X-LINKED HYPOPHOSPHATEMIA GENE CDNA

X-linked hypophosphatemia (XLH), which is a heritable metabolic bone d isease characterized biochemically by selective renal phosphate (Pi) w asting, is associated with mutations in the PEX (Phosphate-regulating gene with homologies to Endopeptidases on the X-chromosome) gene. To f urther explore the physiologic role of PEX and define its effect in XL H we have determined the expression and tissue distribution. Northern analysis found abundant PEX mRNA in a restricted pattern, predominantl y in adult ovary and fetal lung. In addition, PEX expression was also found in adult lung and fetal liver. A PEX cDNA of 2550 basepairs, whi ch contains the full PEX coding region, was isolated from a human ovar y cDNA library. The PEX cDNA shows high homology to other membrane-bou nd zinc metallopeptidases. The presence of PEX in non-osseous tissues strongly suggests features of a systemic role, rather than a unique fu nction in bone development. (C) 1997 Academic Press.