Phosphatidylinositol Glycan A (PIGA)

PIGA encodes a protein required for synthesis of N-acetylglucosaminyl phosphatidylinositol (GlcNAc-PI), the first intermediate in the biosynthetic pathway of GPI anchor. The GPI anchor is a glycolipid found on many blood cells and which serves to anchor proteins to the cell surface. Paroxysmal nocturnal hemoglobinuria, an acquired hematologic disorder, has been shown to result from mutations in this gene. Alternate splice variants have been characterized.

Many cell surface proteins are anchored to the membrane by a glycolipid termed the glycosylphosphatidylinositol (GPI) anchor, which is covalently attached to the C-terminus of the peptide. The core of the GPI anchor consists of multiple components and its biosynthesis involves multiple genes, such as those for glycosyltransferases.