Defective MPI causes MPI-CDG (CDG-1b)

Stable Identifier
Homo sapiens
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Mannose 6-phosphate isomerase (MPI) normally isomerises fructose 6-phosphate (Fru6P) to mannose 6-phosphate (Man6P) in the cytosol. Man6P is a precursor in the synthesis of GDP-mannose and dolichol-phosphate-mannose, required for mannosyl transfer reactions in the N-glycosylation of proteins. Defects in MPI cause congenital disorder of glycosylation 1b (MPI-CDG, previously known as CDG1b,; MIM:602579), a multisystem disorder characterised by under-glycosylated serum glycoproteins (Schollen et al. 2000). Unlike PMM2-CDG (CDG1a), there is no neurological involvement with MPI-CDG. Instead, patients present predominantly with diarrhoea, failure to thrive and protein-losing enteropathy (Pelletier et al. 1986). MPI-CDG is one of two CDGs that can be treated with oral mannose supplementation, but can be fatal if left untreated (Marquardt & Denecke 2003).

Literature References
PubMed ID Title Journal Year
3080572 Secretory diarrhea with protein-losing enteropathy, enterocolitis cystica superficialis, intestinal lymphangiectasia, and congenital hepatic fibrosis: a new syndrome

Pelletier, VA, Galéano, N, Brochu, P, Morin, CL, Weber, AM, Roy, CC

J. Pediatr. 1986
12756558 Congenital disorders of glycosylation: review of their molecular bases, clinical presentations and specific therapies

Marquardt, T, Denecke, J

Eur. J. Pediatr. 2003
10980531 Genomic organization of the human phosphomannose isomerase (MPI) gene and mutation analysis in patients with congenital disorders of glycosylation type Ib (CDG-Ib)

Schollen, E, Dorland, L, de Koning, TJ, Van Diggelen, OP, Huijmans, JG, Marquardt, T, Babovic-Vuksanovic, D, Patterson, M, Imtiaz, F, Winchester, B, Adamowicz, M, Pronicka, E, Freeze, H, Matthijs, G

Hum Mutat 2000
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