DDOST mutations identified by whole-exome sequencing are implicated in congenital disorders of glycosylation.
Am J Hum Genet
; 90(2): 363-8, 2012 Feb 10.
Article
em En
| MEDLINE
| ID: mdl-22305527
ABSTRACT
Congenital disorders of glycosylation (CDG) are inherited autosomal-recessive diseases that impair N-glycosylation. Approximately 20% of patients do not survive beyond the age of 5 years old as a result of widespread organ dysfunction. Although most patients receive a CDG diagnosis based on abnormal glycosylation of transferrin, this test cannot provide a genetic diagnosis; indeed, many patients with abnormal transferrin do not have mutations in any known CDG genes. Here, we combined biochemical analysis with whole-exome sequencing (WES) to identify the genetic defect in an untyped CDG patient, and we found a 22 bp deletion and a missense mutation in DDOST, whose product is a component of the oligosaccharyltransferase complex that transfers the glycan chain from a lipid carrier to nascent proteins in the endoplasmic reticulum lumen. Biochemical analysis with three biomarkers revealed that N-glycosylation was decreased in the patient's fibroblasts. Complementation with wild-type-DDOST cDNA in patient fibroblasts restored glycosylation, indicating that the mutations were pathological. Our results highlight the power of combining WES and biochemical studies, including a glyco-complementation system, for identifying and confirming the defective gene in an untyped CDG patient. This approach will be very useful for uncovering other types of CDG as well.
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Base de dados:
MEDLINE
Assunto principal:
Defeitos Congênitos da Glicosilação
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Exoma
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Hexosiltransferases
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Proteínas de Membrana
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Mutação
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article