Defective DPM3 causes DPM3-CDG

Stable Identifier
Homo sapiens
Defective DPM3 causes CDG-1o
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Dolichyl-phosphate mannosyltransferase (DPM), a heterotrimeric protein embedded in the endoplasmic reticulum membrane, mediates the transfer of mannose (from cytosolic GDP-mannose) to dolichyl phosphate (DOLP) to form dolichyl-phosphate-mannose (DOLPman). The first subunit of the heterotrimer (DPM1) appears to be the actual catalyst, and the other two subunits (DPM2 and 3) appear to stabilise it (Maeda et al. 2000). Defects in DPM3 can cause congenital disorder of glycosylation 1o (DPM3-CDG, CDG1o; MIM:612937), a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterised by under-glycosylated serum glycoproteins. CDG type 1 diseases result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency (Lefeber et al. 2009).

Four biosynthetic pathways depend on DOLPman; N-glycosylation, O-mannosylation, C-Mannosylation and GPI-anchor biosynthesis. A defect in DPM3 strongly reduces O-mannosylation of alpha-dystroglycan, explaining the clinical phenotype of muscular dystrophy and linking the congenital disorders of glycosylation with the dystroglycanopathies (Lefeber et al. 2009).

Literature References
PubMed ID Title Journal Year
19576565 Deficiency of Dol-P-Man synthase subunit DPM3 bridges the congenital disorders of glycosylation with the dystroglycanopathies

Ashida, H, Hess, D, Klein, D, Gr├╝newald, S, Huyben, KM, Morava, E, Manta, P, Lammens, M, Yildiz, J, Sch├Ânberger, J, Evangeliou, A, Hofsteenge, J, Preijers, FW, Wevers, RA, Grafakou, O, van den Elzen, C, Lefeber, DJ, Verrijp, K, Maeda, Y, Guillard, M, Lehle, L, Van den Heuvel, L, Spilioti, M

Am. J. Hum. Genet. 2009
10835346 Human dolichol-phosphate-mannose synthase consists of three subunits, DPM1, DPM2 and DPM3

Kinoshita, T, Kangawa, K, Hino, J, Tanaka, S, Maeda, Y

EMBO J 2000
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