. "The chemical reactions and pathways resulting in the formation of polysaccharide chain component of heparan sulfate proteoglycan." . . . "heparan sulfate proteoglycan biosynthetic process, polysaccharide chain biosynthetic process" . "heparan sulfate proteoglycan anabolism, polysaccharide chain anabolism" . "heparan sulfate proteoglycan chain elongation" . "heparan sulfate proteoglycan formation, polysaccharide chain biosynthesis" . "heparan sulfate proteoglycan formation, polysaccharide chain formation" . "heparan sulfate proteoglycan synthesis, polysaccharide chain synthesis" . "heparan sulphate proteoglycan biosynthesis, polysaccharide chain biosynthesis" . "heparan sulphate proteoglycan biosynthesis, polysaccharide chain biosynthetic process" . "heparin proteoglycan biosynthetic process, polysaccharide chain biosynthetic process" . . .