Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.3.9 (glucose-6-phosphatase)
3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A male child presented at 5 months of age with vomiting, diarrhoea, hypoglycaemia and hepatomegaly. Histology on a frozen liver biopsy suggested glycogen storage disease (GSD), while biochemical analyses confirmed an elevated glycogen content and normal activities of the GSD enzymes with the proviso that a variant of GSD 1 should be considered. The patient presented at 9 months of age with severe lactic acidosis and hypoglycaemia. A glucagon tolerance test and galactose load test on the patient produced no glycaemic response. A second biopsy was obtained and appropriately handled for the investigation of variants of the glucose-6-phosphatase enzyme (G6Pase) complex. Results showed that the patient had a deficiency of two transport proteins of the G6Pase complex, namely glucose-6-phosphate translocase and pyrophosphate translocase, i.e. GSD 1b/1c beta. These results were confirmed by additional kinetic analyses which provided confirmation of the double translocase deficiency. Evidence for inhibitors to these translocases was not found. The patient's treatment has resulted in the hypoglycaemia now being well controlled; however, at 3 years of age, height and weight are markedly lagging and he is moderately developmentally delayed. Neutropenia has not been found and neutrophil function is normal. Double enzyme deficiencies are very rare and possible explanations which might lead to this phenotype are considered. This, to the authors' knowledge, is the first report of a double translocase deficiency causing GSD type 1.
...
PMID:Multiple transport protein defects in a patient with glycogen storage disease type 1: GSD 1b/1c beta. 859 36

Glucose-6-phosphatase is a multicomponent endoplasmic reticulum system comprising at least six different proteins, including a lumenal enzyme and several transport proteins. One of the transport proteins, T2beta, transports the substrate pyrophosphate and the product phosphate and its genetic deficiency is termed type 1c glycogen storage disease. We have used anti-T2beta antibodies for immunohistochemistry with image analysis and kinetic analysis of the glucose-6-phosphatase system to study for the temporal and spatial development of T2beta in human embryonic and fetal kidney. In metanephric kidney, there is an early predominance of T2beta expression in the ureteric bud derivatives and this changes with ontogeny such that developing nephrons, particularly proximal tubules, become dominant by mid-gestation. T2beta has the same spatial and temporal pattern as the glucose-6-phosphatase enzyme in both mesonephric and metanephric kidney. Pyrophosphate transport capacity is appropriate for the amount of glucose-6-phosphatase activity present in mid-gestation fetal kidney, in contrast to liver, where pyrophosphate transport capacity is developmentally delayed. Increasing knowledge of the temporal and spatial expression of the glucose-6-phosphatase proteins and their catalytic roles in early human development is essential for the elucidation of the aetiology of renal disease in both type I glycogen storage diseases and the developmental disorders of the glucose-6-phosphatase system.
...
PMID:The human embryonic-fetal kidney endoplasmic reticulum phosphate-pyrophosphate transport protein. 860 68

Glycogen storage disease type 1a (GSD-1a) is caused by a deficiency in microsomal glucose-6-phosphatase (G6Pase), the key enzyme in glucose homeostasis. A G6Pase knockout mouse which mimics the pathophysiology of human GSD-1a patients was created to understand the pathogenesis of this disorder, to delineate the mechanisms of G6Pase catalysis, and to develop future therapeutic approaches. By examining G6Pase in the liver and kidney, the primary gluconeogenic tissues, we demonstrate that glucose-6-P transport and hydrolysis are performed by separate proteins which are tightly coupled. We propose a modified translocase catalytic unit model for G6Pase catalysis.
...
PMID:Glucose-6-phosphatase dependent substrate transport in the glycogen storage disease type-1a mouse. 864 Feb 27

Polymorphonuclear neutrophils play an important role against pathogens through the production of toxic oxygen metabolites by the NADPH oxidase enzyme, which reduces oxygen to superoxide anion in the respiratory burst. Neutropenia, infectious complications and impaired neutrophil function are often reported in glycogen storage disease type Ib (GSDIb), a metabolic disorder characterized by increased glycogen and decreased glucose-6-phosphatase (G-6-P) activity in the liver. Two children with GSDIb and associated neutropenia with recurrent bacterial infections were treated daily with different doses of rHu-GM-CSF. NADPH oxidase activity and chemotaxis in patients were assessed before and during therapy in stimulated and unstimulated neutrophils. During rHu-GM-CSF treatment, any increase found in the NADPH oxidase activity of patients was not significant with respect to that in controls. In one patient chemotaxis was greater than of controls. This finding suggests that in patients with GSDIb both neutropenia and PMN abnormalities may be responsible for infections, and PMN dysfunction probably depends on the degree of inherited functional G-6-P deficit.
...
PMID:NADPH oxidase activity and chemotaxis by neutrophils in two patients with glycogen storage disease type Ib treated with recombinant human granulocyte-monocyte colony-stimulating factor. 864 44

We studied 20 children with a clinical picture and laboratory study suggestive of hepatic glycogenosis. The age of the beginning of symptoms varied from birth to 24 months and the age at the diagnosis varied from 2 to 81 months. Hepatomegaly was found in all patients, diarrhea in 65% (13/26), "doll-face" in 55% (11/20) and convulsions in 50% (10/20). Nutritional evaluation showed more height deficiency than weight deficiency. Laboratory tests showed elevation of hepatic transaminases (12/19), hypercolesterolemia (8/14), hyperuricemia (6/17) and hypoglycemia (6/20). Liver function was not compromised in most of the cases. The results of glucagon tolerance test were variable. The histoenzymology study performed in 15 patients revealed the following results: Type VI (liver phosphorylase deficiency) in seven, Type I (glucose-6-phosphatase deficiency) in two, Type IV (brancher enzyme) in one and no conclusion could be drawn in five patients. The finding of hypoglycemia in few cases of this study can be justified by the few number of glycogenosis Type I, probably due to the fact that this type is the most easily diagnosed, with less necessity of referring them to specialized centers.
...
PMID:[Hepatic glycogenosis in childhood: clinical and laboratory findings in 20 patients]. 872 90

Both alleles of 24 French glycogen storage disease type 1a patients were sequenced: 14 different mutations allowed the identification of complete genotypes for all the patients. Nine new gene alterations are reported. Five mutations, Q347X, R83C, D38V, G188R, and 158 del C, account for 75% of the mutated alleles. These data show that the molecular pathology of the glucose-6-phosphatase gene is heterogeneous in this population. Complete genotyping of the index case by systematic sequencing is necessary to allow prenatal diagnosis in chorionic villi for at risk couples.
...
PMID:Mutation analysis in 24 French patients with glycogen storage disease type 1a. 873 42

Glycogen storage disease type 1a (GSD 1a), a severe metabolic disorder, is caused by the absence of glucose-6-phosphatase (G6Pase) activity. Diagnosis is currently established by demonstrating the lack of G6Pase activity in the patient's liver specimen. Enzymatic diagnosis cannot be performed in chorionic villi or amniocytes as G6Pase is active only in the liver, kidney, and intestinal mucosa. Recent cloning of the G6Pase gene and subsequent identification of the mutations causing GSD 1a have led to the possibility of performing DNA-based diagnosis in chorionic villus samples (CVS) or amniocytes. Here we report the first DNA-based prenatal diagnosis in two families in whom GSD 1a patients were diagnosed. In one Jewish family with a previously identified R83C mutation, single-stranded conformation polymorphism (SSCP) analysis of the DNA extracted from CVS showed a homozygous R83C mutant pattern. As a result, the pregnancy was terminated and the diagnosis was confirmed on DNA analysis of the aborted fetus. In another family of Arabic extraction in which a V166G mutation has been identified in one of the siblings, SSCP analysis performed on DNA extracted from CVS presented the pattern of a normal control. The pregnancy was carried to term and a healthy baby was born. Thus, once mutations causing the disease are identified, prenatal diagnosis of GSD 1a is possible. SSCP analysis of DNA prepared from CVS is reliable, simple and fast, making it a suitable method for prenatal diagnosis.
...
PMID:Prenatal diagnosis of glycogen storage disease type 1a by single stranded conformation polymorphism (SSCP). 890 2

Type Ia glycogen storage disease (GSD), an autosomal recessive metabolic disorder, is caused by a deficiency in glucose-6-phosphatase (G6Pase). We had previously identified the nature of the causative mutations in a Chinese family whose first two children were affected with type Ia GSD. Two different point mutations in the G6Pase gene, a guanine to adenine substitution at base position 327 in exon 2 and a thymine to adenine substitution at base position 1101 in exon 5, change the restriction sites for the enzymes Fok I and Hinc II. Family study revealed that both parents were heterozygous carriers: the father with a mutant G6Pase allele at exon 2 and the mother with another mutant G6Pase allele at exon 5. This paper deals with a prenatal diagnosis on the fetus of this family who is at risk of type Ia GSD. Genomic DNA was extracted from a chorionic villus biopsy sampled at the tenth week of gestation. Exons 2 and 5 of the G6Pase gene were amplified by the polymerase chain reaction (PCR) followed by restriction enzyme digestion and direct sequence analysis. DNA analysis indicated that the fetus was a heterozygous carrier of type Ia GSD with a mutant G6Pase allele at exon 2 and a normal G6Pase allele at exon 5. The diagnosis was further confirmed by the same method with cultured amniocytes and with a blood sample after the baby was born. This is the first report of prenatal carrier detection of type Ia GSD at the gene level.
...
PMID:Prenatal diagnosis in a Chinese family with type Ia glycogen storage disease by PCR-based genetic analysis. 895 36

Type 1a glycogen storage disease (GSD) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). Polymerase chain reaction (PCR) and nucleotide sequence analysis were used to identify the location and nature of mutations at the G6Pase locus in two siblings affected with type 1a GSD. Both patients are compound heterozygotes with two different single nucleotide substitutions in the two G6Pase alleles. A guanine to adenine transition was identified at base position 327 in the exon 2, converting an arginine to a histidine at codon 83. The second substitution was a thymine to adenine transversion at base position 1101 in the exon 5, converting an isoleucine to an asparagine at codon 341. Family study reveals that both parents are heterozygous carriers: the father with a mutant G6Pase allele at exon 2, the mother with another mutant G6Pase allele at exon 5. This is the first family study in Taiwan on type 1a GSD identified by molecular analysis. The mutations identified herein are novel substitutions in the G6Pase gene. In addition, an adenine to guanine substitution was observed at base position 653 in the exon 5 of G6Pase gene in both sibling patients and their parents, as well as in 15 normal Chinese subjects and three normal Caucasian subjects.
...
PMID:Genetic analysis of the glucose-6-phosphatase mutation of type 1a glycogen storage disease in a Chinese family. 900

Glycogen storage disease type 1a (GSD 1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase gene of two unrelated Japanese families with GSD 1a. DNA sequencing of all five exons and exon-intron junctions revealed a G-to-T transversion at nucleotide 727 (G727T) in exon 5, which has been previously reported to cause abnormal splicing. Family studies using mismatch PCR showed that three patients were homozygous for the G727T mutation, while the parents were heterozygous. To investigate allele frequencies, we screened 216 Japanese healthy volunteers and found one asymptomatic carrier. Our findings suggest that the G727T mutation may be prevalent in Japan.
...
PMID:Identification of a point mutation (G727T) in the glucose-6-phosphatase gene in Japanese patients with glycogen storage disease type 1a, and carrier screening in healthy volunteers. 913 83


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---