Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:5.4.2.8 (phosphomannomutase)
 238 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The carbohydrate-deficient glycoprotein syndromes are multisystemic inherited diseases with severe nervous system involvement. There is indirect evidence for deficiency of phosphomannomutase in type I and direct evidence for a deficiency of N-acetylglucosaminyltransferase II in type II. The disease is characterized by carbohydrate deficiencies of a number glycoproteins, including serum sialotransferrins.
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PMID:[Metabolic disorders in patients with primary carbohydrate deficient glycoprotein syndrome]. 923 66

The carbohydrate-deficient glycoprotein (CDG) syndromes (CDGS) are a series of autosomal recessive enzyme deficiencies which result in incomplete glycosylation of plasma proteins. CDGS types Ia and Ib have been related to deficiencies of phosphomannomutase and phosphomannose isomerase, respectively, while CDGS type II results from a deficiency of N-acetylglucosaminyltransferase II. Secondary CDG syndromes are associated with galactosaemia and hereditary fructose intolerance. The diagnosis of CDGS is most easily made by studying the glycoforms of suitable marker proteins using either electrophoresis or isoelectric focusing. This paper reviews the structure of the glycan chains of proteins and structural alterations in CDGS. It also outlines analytical techniques which are useful in the laboratory study of protein glycoforms and the diagnosis of CDGS.
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PMID:Carbohydrate-deficient glycoprotein syndromes: inborn errors of protein glycosylation. 1037 Jul 57

Carbohydrate-deficient glycoprotein syndromes are rare, multisystemic diseases, typically with major nervous system impairment, that are caused by hypo- and unglycosylation of N-linked glycoproteins. Hence, a biochemical evidence of this abnormality, like hypoglycosylation of serum transferrin is essential for diagnosis. Clinically and biochemically, six types of the disease have been delineated. Three of them are caused by deficiencies of the enzymes that are required for a proper glycosylation of lipid--(dolichol) linked oligosaccharide (phosphomannomutase or phosphomannose isomerase or alpha-glycosyltransferase), and one results from a deficiency of Golgi resident N-acetylglucosaminyltransferase II. In addition one variant of the disease has been reported as due to a defective biosynthesis of dolichol iself. The diseases are heritable but genetics has been established for only two types. Therapy, based on administration of mannose to patients is currently under investigation. It benefits patients with deficiency of phosphomannose isomerase. Taking into account the complexity of N-linked glycosylation of proteins more of the disease variants is expected to be found.
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PMID:Carbohydrate-deficient glycoprotein syndromes. 1069 81

Congenital disorders of glycosylation (CDG) type I are mostly due to a deficient phosphomannomutase activity, called CDG Ia. CDG IIa (mutations in the MGAT2 gene) results from a deficient activity of the Golgi enzyme N-acetylglucosaminyltransferase II. CDG Ia patients predominantly have a thrombotic tendency, whereas our CDG IIa patient has an increased bleeding tendency, despite similar coagulation factor abnormalities in both types. We have investigated whether abnormally glycosylated platelet membrane glycoproteins are involved in the haemostatic complications of both CDG groups. In flow cytometry, the binding of Ricinus communis lectin (reactive with beta-galactose primarily) to control platelets increased after neuraminidase treatment: this increase was smaller (p < 0.01) in CDG Ia patients (3.1 +/- 0.08 times) than in control platelets (8.5 +/- 1.8 times) and did not occur in the CDG IIa patient. Platelet-rich plasma from CDG Ia patients, but not a CDG IIa patient. aggregated spontaneously and gel-filtered platelets from CDG Ia patients agglutinated at very low concentrations of ristocetin, independently of von Willebrand factor (vWF). Accordingly, in stirred whole blood, the rate of single platelet disappearance of CDG Ia patients was twice that of control platelets. In contrast, perfusion of whole anticoagulated blood of the CDG IIa patient over collagen yielded markedly decreased platelet adherence to collagen at shear rates involving glycoprotein (GP) Ib-vWF interactions. Thus, abnormal glycosylation of platelet glycoproteins in CDG Ia enhances nonspecific platelet interactions, in agreement with a thrombotic tendency. The reduced GP Ib-mediated platelet reactivity with vessel wall components in the CDG IIa patient under flow conditions provides a basis for his bleeding tendency.
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PMID:Congenital disorders of glycosylation type Ia and IIa are associated with different primary haemostatic complications. 1159 51