Phosphatidylinositol Glycan F (PIGF)

PIGF encodes 1 of the enzymes involved in glycosylphosphatidylinositol (GPI) anchor biosynthesis. The primary biochemical defect in paroxysmal nocturnal hemoglobinuria (PNH), an acquired hematologic disorder with protean clinical manifestations including recurrent episodes of hemolysis, infections, and venous thrombosis, involves defective synthesis of GPI anchors that attach certain proteins to the cell surface membrane.

Proteins with appropriate C-terminal signal peptides are transferred to the preformed glycolipid anchor in the endoplasmic reticulum and transported to the cell surface as a single unit; in PNH, there is a defect in GPI-anchor biosynthesis and an absence of all surface proteins that use this anchoring motif.