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)

Carbohydrate deficient glycoprotein syndromes (CDGS) are inherited disorders in glycosylation. Isoelectric focusing of serum transferrin is used as a biochemical indicator of CDGS; however, this technique cannot diagnose the molecular defect. Even though phosphomannomutase (PMM) deficiency accounts for the great majority of known CDGS cases (CDGS type Ia), newly discovered cases have significantly different clinical presentations than the PMM-deficient patients. These differences arise from other defects affecting the biosynthesis of N-linked oligosaccharides in the endoplasmic reticulum and in the Golgi compartment. The most notable is the loss of phosphomannose isomerase (PMI) (CDGS type Ib). It causes severe hypoglycemia, protein-losing enteropathy, vomiting, diarrhea, and congenital hepatic fibrosis. In contrast to PMM-deficiency, there is no developmental delay nor neuropathy. Most symptoms in the PMI-deficient patients can be successfully treated with dietary mannose supplements. Another defect is the lack of glucosylation of the lipid-linked oligosaccharide precursor. The clinical features of this form of CDGS are milder, but similar to, PMM-deficient patients. Yeast genetic and biochemical techniques were critical in unraveling these disorders since many of the defective genes were known in yeast and corresponding mutants were available for complementation. Yeast strains carrying mutations in the homologous genes are likely to provide conclusive identification of the primary defects in novel CDGS types that affect the synthesis and transfer of precursor oligosaccharides.
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PMID:Molecular basis of carbohydrate-deficient glycoprotein syndromes type I with normal phosphomannomutase activity. 1057 Oct 10

A male infant is described who presented with persistent hyperinsulinaemic hypoglycaemia, responding to diazoxide treatment. However, this therapy was discontinued because of seizures as a consequence of disturbed water and electrolyte balance. Glucose homeostasis could only be maintained by subtotal pancreatectomy, which was performed at 3 8/12 years of age. He developed a severe thrombosis, whereon a congenital disorder of glycosylation (CDG) was suspected. An abnormal transferrin isoelectric focusing pattern was found and the diagnosis of CDG Ia was confirmed by enzyme and molecular genetic analysis. This is the first patient with phosphomannomutase deficiency (McKusick 601785) described presenting with severe hyperinsulinaemic hypoglycaemia.
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PMID:Hyperinsulinaemic hypoglycaemia--leading symptom in a patient with congenital disorder of glycosylation Ia (phosphomannomutase deficiency). 1191 19

Phosphomannose isomerase (PMI) deficiency (CDG-Ib) is a newly recognized disorder of mannose and glycoprotein metabolism. PMI deficiency manifests itself mainly as a gastrointestinal disorder with protein-losing enteropathy and life-threatening intestinal bleeding. Hypoglycaemia is an additional prominent symptom. In contrast to phosphomannomutase deficiency (CDG-Ia), there are no neurological symptoms. PMI deficiency blocks the endogenous mannose formation from glucose. Exogenous oral mannose supply bypasses the enzymatic block and leads to the disappearance of all symptoms in the patient. The striking ultrastructural abnormalities of the rough endoplasmatic reticulum of the duodenal epithelial cells completely normalize and the hypoglycosylation disappears, as evidenced by the normal isoelectric focusing pattern of serum transferrin, the standard diagnostic procedure for recognition of CDG. This paper includes a detailed description of the clinical symptomatology of the first-ever diagnosed and treated patient with PMI deficiency and a 5-y follow-up study of mannose therapy.
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PMID:Oral mannose therapy persistently corrects the severe clinical symptoms and biochemical abnormalities of phosphomannose isomerase deficiency. 1243 92

We describe three patients with congenital disorder of glycosylation (CDG) type Ia, all of whom had persistent hyperinsulinaemic hypoglycaemia responding to diazoxide therapy as a common feature. The first patient, an infant girl, presented with recurrent vomiting, failure to thrive, liver impairment, hypothyroidism and a pericardial effusion. The second patient, also female, had a milder disease with single organ involvement, presenting as isolated hyperinsulinaemic hypoglycaemia, not associated with any cognitive impairment. The third patient, a boy presented with multi-organ manifestations including congenital hypothyroidism, persistent hyperinsulinaemic hypoglycaemia, coagulopathy, olivopontocerebellar hypoplasia and recurrent pancreatitis. All three patients had a type 1 serum transferrin isoform pattern, and were subsequently found to have low phosphomannomutase activity, confirming the diagnosis of CDG type Ia. Our findings emphasize that CDG should be considered as a differential diagnosis in patients with persistent hyperinsulinaemic hypoglycaemia and that it may even occasionally be the leading symptom in CDG Ia.
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PMID:Congenital disorder of glycosylation type Ia: heterogeneity in the clinical presentation from multivisceral failure to hyperinsulinaemic hypoglycaemia as leading symptoms in three infants with phosphomannomutase deficiency. 1939 70