Cell surface heparan sulfate proteoglycans are composed of a membrane-associated protein core substituted with a variable number of heparan sulfate chains. Members of the glypican-related integral membrane proteoglycan family (GRIPS) contain a core protein anchored to the cytoplasmic membrane via a glycosyl phosphatidylinositol linkage. These proteins may play a role in the control of cell division and growth regulation. Deletion mutations in this gene are associated with Simpson-Golabi-Behmel syndrome. (Also known as glypican 3; Intestinal protein OCI-5; GTR2-2; MXR7; Glypican-3 precursor).