Identification and functional analysis of a defect in the human ALG9 gene: definition of congenital disorder of glycosylation type IL.

ABSTRACT: Defects of lipid-linked oligosaccharide assembly lead to alterations of N-linked glycosylation known as "type I congenital disorders of glycosylation" (CDG). Dysfunctions along this stepwise assembly pathway are characterized by intracellular accumulation of intermediate lipid-linked oligosaccharides, the detection of which contributes to the identification of underlying enzymatic defects. Using this approach, we have found, in a patient with CDG, a deficiency of the ALG9 alpha 1,2 mannosyltransferase enzyme, which causes an accumulation of lipid-linked-GlcNAc(2)Man(6) and -GlcNAc(2)Man(8) structures, which was paralleled by the transfer of incomplete oligosaccharides precursors to protein. A homozygous point-mutation 1567G-->A (amino acid substitution E523K) was detected in the ALG9 gene.

SUBMITTER: Frank CG 

PROVIDER: S-EPMC1181998 | biostudies-literature | 2004 Jul

REPOSITORIES: biostudies-literature