Defective ALG12 does not add mannose to the N-glycan precursor

Stable Identifier
Reaction [transition]
Homo sapiens
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Dol-P-Man:Man(7)GlcNAc(2)-PP-Dol alpha-1,6-mannosyltransferase (ALG12) (Chantret et al. 2002) normally tranfers the 8th mannose moiety to the lipid-linked oligosaccharide (LLO aka N-glycan precursor) which is required for subsequent N-glycosylation of proteins. Defects in ALG12 are associated with congenital disorder of glycosylation 1g (ALG12-CDG, CDG1g; MIM:607143), a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterised by under-glycosylated serum glycoproteins (Chantret et al. 2002, Grubenmann et al. 2002). CDG type 1 diseases result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. Point mutations that can cause ALG12-CDG are F142V, T67M, R146Q, G101R, L158P and Y414* (Chantret et al. 2002, Grubenmann et al. 2002).
Literature References
PubMed ID Title Journal Year
11983712 Congenital disorders of glycosylation type Ig is defined by a deficiency in dolichyl-P-mannose:Man7GlcNAc2-PP-dolichyl mannosyltransferase

Dupré, T, Danos, O, Chantret, I, Bader-Meunier, B, Seta, N, Bucher, S, Barnier, A, Heron, D, Durand, G, Codogno, P, Oriol, R, Moore, SE, Delenda, C, Charollais, A, Dancourt, J

J Biol Chem 2002
12217961 ALG12 mannosyltransferase defect in congenital disorder of glycosylation type lg

Berger, EG, Grubenmann, CE, Kjaergaard, S, Frank, CG, Hennet, T, Aebi, M

Hum. Mol. Genet. 2002
Catalyst Activity

mannosyltransferase activity of ALG12 mutants [endoplasmic reticulum membrane]

Normal reaction
Functional status

Loss of function of ALG12 mutants [endoplasmic reticulum membrane]

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