Mutations in the PIGV, PIGO, PIGL, PIGY, PGAP2, PGAP3, and PIGW genes have recently been reported to cause hyperphosphatasia accompanied by mental retardation syndrome (HPMRS); the latter is an autosomalrecessive neurological disorder typically characterised by recurrent seizures, intellectual disability, and distinct facial features. | Mutations in the PIGW gene associated with hyperphosphatasia and mental retardation syndrome: A case report