biostudies-literatureUnknown75(1)Frank CGDefects 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.American journal of human genetics146-50https://www.ebi.ac.uk/biostudies/studies/S-EPMC1181998biostudies-literatureIdentification and functional analysis of a defect in the human ALG9 gene: definition of congenital disorder of glycosylation type IL.PMC1181998Aebi MBerger EGGrubenmann CEHennet TFrank CGEyaid WfalseIdentification and functional analysis of a defect in the human ALG9 gene: definition of congenital disorder of glycosylation type IL.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.2004-01-01T00:00:00Z2004 Jul2025-04-04T21:07:08.75Z2019-03-27T01:09:11ZS-EPMC11819981514865610.1086/422367