PIGW deficiency is caused by the mutation of PIGW, an acyltransferase which transfers acyl-chain to the inositol ring of GlcN-PI to generate GlcN-(acyl)PI, the fourth step of the GPI biosynthesis. This disease is caused by the decreased expression of various GPI-anchored proteins (GPI-APs), which serve critical functions as adhesion molecules, receptors, complement regulators, enzymes and co-receptors in signal transduction pathways. The main clinical features are intellectual disability, developmental delay, severe encephalopathy, an early-onset epilepsy such as West syndrome, facial dysmorphism, organ anomalies, brachyphalangy, hypotonia, contractures and hyperphosphatasia. The prevalence of PIGW deficiency is unknown as it is recently recognized disease, but there have been 11 patients reported. The PIGW gene is located on chromosome 17q12, and PIGW deficiency is autosomal recessive disorder.
PIGW