Defective MGAT2 causes CDG-2a

Alpha-1,6-mannosyl-glycoprotein 2-beta-N-acetylglucosaminyltransferase (MGAT2) normally catalyses the transfer of a GlcNAc moiety onto the alpha-1,6 mannose of an alpha-1,4 branch of oligomannose N-glycans to form complex N-glycans. Defects in MGAT2 are associated with congenital disorder of glycosylation type IIa (MGAT2-CDG, CDG-2a; MIM:212066), a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterised by under-glycosylated serum glycoproteins. Type II CDGs refer to defects in the trimming and processing of protein-bound glycans.

Summary from Reactome (R-HSA-4793952), read 2026-09-23.