STRUCTURES AND CHROMOSOMAL LOCALIZATIONS OF THE GLYCOSYLPHOSPHATIDYLINOSITOL SYNTHESIS GENE PIGC AND ITS PSEUDOGENE PIGCP1

More than 10 genes are involved in the biosynthesis of glycosylphospha tidylinositol (GPI), which anchors many mammalian cell surface protein s to the membrane. Paroxysmal nocturnal hemoglobinuria (PNH) is caused by a somatic mutation in a GPI biosynthesis gene within the hematopoi etic stem cell. The X-linked gene PIGA has been found to be mutated in all patients with PNH. This is probably because all other GPI synthes is genes are autosomal; hence two somatic mutations must occur to caus e PNH, whereas one somatic mutation is sufficient to inactivate PIGA. Consistent with this notion, three other genes, PIGB, PIGF, and PIGH, are autosomal. Here we isolated a genomic clone of another GPI-synthes is gene, PIGC, and mapped it to chromosome 1q23-q25, further supportin g this notion. PIGC is an intronless gene. We found an intronless pseu dogene of PIGC, PIGCP1, and mapped it to chromosome 11p12-p13. The pre sence of a processed pseudogene is a common feature of PIGA, PIGF, and PIGC. (C) 1997 Academic Press.