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, PubMed:9463366). Interacts with PIGQ (PubMed:9463366). Interacts with the heterodimer PIGA:PIGH (PubMed:9463366). The disease is caused by variants affecting the gene represented in this entry. Belongs to the PIGC family. Phosphatidylinositol N-acetylglucosaminyltransferase subunit C8