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

Carbohydrate-deficient glycoprotein syndrome type 1 (CDG1 or Jaeken syndrome) is the prototype of a class of genetic multisystem disorders characterized by defective glycosylation of glycoconjugates. It is mostly a severe disorder which presents neonatally. There is a severe encephalopathy with axial hypotonia, abnormal eye movements and pronounced psychomotor retardation, as well as a peripheral neuropathy, cerebellar hypoplasia and retinitis pigmentosa. The patients show a peculiar distribution of subcutaneous fat, nipple retraction and hypogonadism. There is a 20% lethality in the first years of life due to severe infections, liver insufficiency or cardiomyopathy. CDG1 shows an autosomal recessive mode of inheritance and has been mapped to chromosome 16p. Most patients show a deficiency of phosphomannomutase (PMM)8, an enzyme necessary for the synthesis of GDP-mannose. We have cloned the PMM1 gene, which is on chromosome 22q13 (ref.9). We now report the identification of a second human PMM gene, PMM2, which is located on 16p13 and which encodes a protein with 66% identity to PMM1. We found eleven different missense mutations in PMM2 in 16 CDG1 patients from different geographical origins and with a documented phosphomannomutase deficiency. Our results give conclusive support to the biochemical finding that the phosphomannomutase deficiency is the basis for CDG1.
 ...
PMID:Mutations in PMM2, a phosphomannomutase gene on chromosome 16p13, in carbohydrate-deficient glycoprotein type I syndrome (Jaeken syndrome). 914 Apr 1

Carbohydrate-deficient glycoprotein syndrome consists of a group of disorders with multisystemic involvement and prominent neurologic symptoms. The full clinical spectrum continues to evolve, with four types currently recognized; type I is by far the most common. The clinical presentation of CDGS appears more severe in infants than in adults. Diagnosis is based on the clinical findings of characteristic fat distribution, neurologic impairment, and developmental delay, combined with the biochemical finding of cathodally migrating serum glycoproteins, transferrin in particular, on isoelectric focusing. Scientific evidence supports the hypothesis that abnormal synthesis of N-linked oligosaccharides is the basic metabolic defect in CDGS. The complex, multistep nature of the N-linked oligosaccharide pathway and the clinical heterogeneity of CDGS suggest that several different defects in the pathway can result in this disorder. Two specific enzyme defects have been reported: phosphomannomutase deficiency in some type I patients and N-acetylglucosamine transferase II deficiency in type II patients. Investigations continue into other metabolic bases of CDGS. The discovery of some of the enzyme defects paves the way for cloning, mutational analysis, and eventually prenatal diagnosis in appropriate families. No known treatment exists for CDGS; pallintive care and support is the most that can be offered. Family support systems are blossoming both in the United States and abroad, giving families the ability to communicate with each other and with workers in the field. As more cases are diagnosed and scientific research continues, advances in clinical definition, supportive care, nutrition, and prenatal diagnosis of CDGS are inevitable.
 ...
PMID:Carbohydrate-deficient glycoprotein syndrome. 926 69

To report the first case of carbohydrate deficient glycoprotein syndrome Type I (CDG I) that has been identified in Australia and confirmed enzymatically to raise the awareness of paediatricians with regard to CDG I and its manifestations, implications and diagnostic investigations. Clinical and autopsy findings of an infant with CDG I are presented. The diagnosis of CDG I was suggested by the clinical findings and biochemical abnormalities and was confirmed by showing an abnormal transferrin isoform pattern. Subsequent studies showed a reduced level of phosphomannomutase in skin fibroblasts. Carbohydrate-deficient glycoprotein syndrome I is one of the many causes of cerebellar hypoplasia. It is an important disorder to identify because of the prognostic and genetic implications and may be underdiagnosed in Australia.
 ...
PMID:Carbohydrate deficient glycoprotein syndrome type I: a cause of cerebellar vermis hypoplasia. 948 87

Carbohydrate-deficient glycoprotein syndrome type 1 (CDG1; McKusick No. 212065) is an autosomal recessively inherited disease characterised clinically by central nervous system dysfunction and biochemically by hypoglycosylation of many serum proteins. Most patients with CDG1 have deficient activity of phosphomannomutase. The locus for this enzyme has been mapped to 16p13, and a gene, PMM2, encoding phosphomannomutase has been isolated. We identified 34 mutations on 36 disease chromosomes in 18 unrelated Danish patients with CDG1. All patients have less than 15% residual activity of phosphomannomutase. Two mutations account for 88% of all mutations: F119L and R141H were each found in 16 out of 36 CDG1 alleles. These two mutations were found to be in linkage disequilibrium with two different alleles of the marker D16S3020, suggesting that there is one ancestral origin for each mutation. Two new mutations, G117R and D223E, were identified also. Surprisingly, no patient was homozygous for either of the two common mutations, suggesting that homozygosity for these mutations is either lethal or so benign that such patients are not detected.
 ...
PMID:Absence of homozygosity for predominant mutations in PMM2 in Danish patients with carbohydrate-deficient glycoprotein syndrome type 1. 978 Oct 39

Carbohydrate-deficient glycoprotein syndrome type 1 (CDG1) is an autosomal recessive, metabolic disorder with severe psychomotor retardation and a high mortality rate in early childhood. Most patients have a deficiency of phosphomannomutase, due to mutations in PMM2, a gene located on chromosome 16p13. Over a period of 18 months we offered prenatal diagnosis to eight families. In six cases and prior to the identification of the gene, the diagnosis was based on linkage analysis and phosphomannomutase measurements. Subsequently direct mutation analysis has been used in two families. It is shown here that phosphomannomutase activities are strongly reduced in cultured amniocytes and trophoblasts of affected foetuses. We refrained from offering prenatal testing in two other families, because either the disease did not link to chromosome 16 and/or normal phosphomannomutase activities were measured in fibroblasts from the proband. This confirms earlier suggestions of heterogeneity for CDG1.
 ...
PMID:Prenatal diagnosis in CDG1 families: beware of heterogeneity. 978 Oct 52

Carbohydrate-deficient glycoprotein syndrome type Ia (CDGS) is an autosomal recessive disorder, characterized by a central nervous system dysfunction and multiorgan failure associated with defective N-glycosylation and phosphomannomutase (PMM) deficiency related to mutations in the PMM2 gene. A total of 26 different missense mutations and one single base pair deletion have already been described. We found by sequencing and restriction analysis, in two unrelated French patients with CDG type Ia a compound heterozygosity for two mutations in exon 5: a new mutation 415G>A (E139K) and the most frequent mutation 425G>A (R141H ). The 415G>A mutation disrupted a splicing enhancer sequence: (GAR)n-(GAR)n resulting in exon 5 skipping. We studied the activity of these mutant proteins expressed in E Coli. Compared to the normal PMM protein activity, the R141H and transcript without exon 5 expressed a protein with undetectable specific activity when the E139K mutant protein expressed a residual activity of 25%. The E139K mutant protein could be expressed at a sufficient level in vivo to confer residual activity compatible with life in these patients when absence of residual PMM activity is likely lethal.
 ...
PMID:Characterization of the 415G>A (E139K) PMM2 mutation in carbohydrate-deficient glycoprotein syndrome type Ia disrupting a splicing enhancer resulting in exon 5 skipping. 1057 56