Predominantly fucosylates the innermost N-acetyl glucosamine (GlcNAc) residue in biantennary N-glycan acceptors. Postulated to generate core alpha(1->3)-fucose epitope within the chitobiose unit of biantennary N-glycans, providing for a recognition signal to reorient aberrantly folded glycoproteins for degradation (PubMed:19088067). Involved in biosynthesis of Lewis X-carrying biantennary N-glycans that regulate neuron stem cell self-renewal during brain development (By similarity). Catalyzes the transfer of fucosyl moiety from GDP-beta-L-fucose to the innermost GlcNAc residue in biantennary N-glycan acceptors. Does not fucosylate GlcNAc within type 2 lactosamine unit. Catalyzes the transfer of fucosyl moiety from GDP-beta-L-fucose to the innermost GlcNAc residue in biantennary N-glycan acceptors. Does not fucosylate GlcNAc within type 2 lactosamine unit. Catalyzes the transfer of fucosyl moiety from GDP-beta-L-fucose to the innermost GlcNAc residue in biantennary N-glycan acceptors. Does not fucosylate GlcNAc within type 2 lactosamine unit. Protein modification; protein glycosylation. Expressed in lung, digestive tract, gall bladder, placenta, kidney, uterus and brain. Not detected in spleen, heart, muscle, liver and pancreas. Expressed in fetal tissues including skin, small intestine, liver, kidney, lung, muscle, heart and brain. Expressed in 50 day old embryo. Expressed in 50 day old embryo. Belongs to the glycosyltransferase 10 family.