Glycosyltransferase which regulates the biosynthesis of heparan sulfate (HS). Important for both skeletal development and hematopoiesis, through the formation of HS proteoglycans (HSPGs) (PubMed:28132690, PubMed:28148688). Required for the function of REG3A in regulating keratinocyte proliferation and differentiation (PubMed:22727489). 3-O-(beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + UDP-N-acetyl-alpha-D-glucosamine = 3-O-(alpha-D-GlcNAc-(1->4)-beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + H(+) + UDP Glycan metabolism; heparan sulfate biosynthesis. Interacts with REG3A. Ubiquitous. Expressed in keratinocytes. The disease is caused by variants affecting the gene represented in this entry. Belongs to the glycosyltransferase 47 family. It is uncertain whether Met-1, Met-6 or Met-20 is the initiator. Extended N-terminus. Exostosin-like 3