PIGA cDNA Clone – Phosphatidylinositol Glycan Anchor Biosynthesis, Class A (Human)

This gene 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. A related pseudogene is located on chromosome 12. [provided by RefSeq, Jun 2010]

PIGA: Necessary for the synthesis of N-acetylglucosaminyl- phosphatidylinositol, the very early intermediate in GPI-anchor biosynthesis. Defects in PIGA are the cause of paroxysmal nocturnal hemoglobinuria (PNH). PNH is a disorder characterized by hemolytic anemia with hemoglobinuria, thromboses in large vessels, and a deficiency in hematopoiesis. Clinical manifestation of red blood cell breakdown with release of hemoglobin into the urine is manifested most prominently by dark-colored urine in the morning. Defects in PIGA are the cause of multiple congenital anomalies-hypotonia-seizures syndrome type 2 (MCAHS2). An X-linked recessive developmental disorder characterized by dysmorphic features, neonatal hypotonia, myoclonic seizures, and variable congenital anomalies involving the central nervous, cardiac, and urinary systems. Most affected individuals die in infancy. Belongs to the glycosyltransferase group 1 family. Glycosyltransferase 4 subfamily. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Transferase; Glycan Metabolism - glycosylphosphatidylinositol (GPI)-anchor biosynthesis; EC 2.4.1.198; Membrane protein, integral

Chromosomal Location of Human Ortholog: Xp22.1

Cellular Component: endoplasmic reticulum membrane; glycosylphosphatidylinositol-N-acetylglucosaminyltransferase (GPI-GnT) complex; membrane

Molecular Function: phosphatidylinositol N-acetylglucosaminyltransferase activity; protein binding; UDP-glycosyltransferase activity

Biological Process: GPI anchor biosynthetic process; positive regulation of metabolic process; preassembly of GPI anchor in ER membrane

Disease: Multiple Congenital Anomalies-hypotonia-seizures Syndrome 2; Paroxysmal Nocturnal Hemoglobinuria 1