Defective B4GALT1 does not transfer Gal to a branch of keratan

Stable Identifier
Reaction [transition]
Homo sapiens
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The family of beta 4-galactosyltransferases (B4GALTs) is composed by at least six known members that mediate the transfer of galactose to N-glycan structures and either to begin or elongate keratan chains. Defective B4GALT1 is associated with congenital disorder of glycosylation type IId (B4GALT1-CDG, CDG-2d; MIM:607091), in which clinical symptoms are dominated by dysmorphic features, psychomotor and mental retardation, hypotonia, as well as blood coagulation abnormalities (Hansske et al. 2002). The mutant R345Kfs*6 results in a truncated, inactive polypeptide. Analysis of oligosaccharides from serum transferrin from these patients reveals loss of sialic acid and galactose residues (Hansske et al. 2002).

Literature References
PubMed ID Title Journal Year
11901181 Deficiency of UDP-galactose:N-acetylglucosamine beta-1,4-galactosyltransferase I causes the congenital disorder of glycosylation type IId

Hoffmann, GF, Lübke, T, Peters, V, Hansske, B, Körner, C, Heidemann, PH, von Figura, K, Berger, EG, Höning, S, Thiel, C, Hasilik, M

J Clin Invest 2002
Catalyst Activity

beta-N-acetylglucosaminylglycopeptide beta-1,4-galactosyltransferase activity of B4GALT1 R345Kfs*6 [Golgi membrane]

Normal reaction
Functional status

Loss of function of B4GALT1 R345Kfs*6 [Golgi membrane]

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