A case with congenital disorder of glycosylation with defective fucosylation 2 and new mutation in FUK gene

Congenital disorders of glycosylation (CDG) is a group of rare, hereditary, multisystem disorders, predominantly affecting nervous system. There are N- and O- types of glycosylation. Fucosylation, a form of N-glycosylation, involves many enzymes. Until today, type 1 and type 2 fucosylation defects were identified, having pathogenic variants in genes encoding α-1,6-fucosyltransferase and fucokinase enzymes, respectively. In this article, a patient with type 2 fucosylation defect will be presented, with hypotonia, developmental delay and blindness and a pathogenic variant that was previously described in two patients.