FUT8 and inborn errors of metabolism: Bi-allelic mutations in the FUT8 gene, resulting in defective FUT8 α1,6 fucosyltransferase activity and the absence of the core-fucosylated N-glycans, lead to the development of the severe metabolic congenital disorder of glycosylation with defective fucosylation 1 (FUT8-CDG) in humans [26].