PIGN (Phosphatidylinositol Glycan Anchor Biosynthesis Class N) is a gene involved in the synthesis of glycosylphosphatidylinositol (GPI) anchors, which attach specific proteins to the cell membrane. These GPI-anchored proteins are crucial for functions such as cell adhesion, signal transmission, and immune system activity. Mutations in PIGN can impair GPI anchor formation, resulting in disorders characterised by developmental delays, neurological issues, and congenital abnormalities.