Glycosylphosphatidylinositol Biosynthesis Defect 11, also known as hyperphosphatasia with mental retardation syndrome 5, is related to cleft palate, isolated, and has symptoms including tonic seizures An important gene associated with Glycosylphosphatidylinositol Biosynthesis Defect 11 is PIGW (Phosphatidylinositol Glycan Anchor Biosynthesis Class W), and among its related pathways/superpathways is 17q12 copy number variation syndrome. Related phenotypes are high palate and coarse facial features