PIGW (phosphatidylinositol glycan anchor biosynthesis class W) encodes an acyltransferase that catalyzes acyl transfer during glycosylphosphatidylinositol (GPI) anchor biosynthesis, specifically the attachment of acyl groups to the inositol ring of glucosaminyl phosphatidylinositol 1. This acylation is essential for the transport of GPI-anchored proteins to the plasma membrane 1. Biallelic PIGW mutations cause glycosylphosphatidylinositol biosynthesis defect 11 (GPIBD11), also known as hyperphosphatasia with mental retardation syndrome 23. GPIBD11 is a severe multisystemic disorder characterized by developmental delay, early-onset seizures (commonly epileptic spasms), intellectual disability, distinctive facial features, recurrent respiratory infections, and elevated serum alkaline phosphatase 43. Additional manifestations include cardiac anomalies, neurological abnormalities, and multiple organ involvement affecting skeletal and genitourinary systems, with variable severity ranging from prenatal lethality to atypical milder phenotypes 456. Flow cytometry demonstrates significantly reduced GPI-anchored protein expression in patient blood samples 5. The disorder requires complex multidisciplinary management with uncertain long-term prognosis 4.