Part of the glycosylphosphatidylinositol-N-acetylglucosaminyltransferase (GPI-GnT) complex that catalyzes the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to phosphatidylinositol and participates in the first step of GPI biosynthesis. Glycolipid biosynthesis; glycosylphosphatidylinositol-anchor biosynthesis. Component of the glycosylphosphatidylinositol-N-acetylglucosaminyltransferase (GPI-GnT) complex composed at least by PIGA, PIGC, PIGH, PIGP, PIGQ, PIGY and DPM2 (PubMed:16162815). Interacts directly with PIGA and PIGQ (PubMed:10944123). Ubiquitous. The disease is caused by variants affecting the gene represented in this entry. Belongs to the PIGP family.