Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019209 (hepatomegaly)
 5,798 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:[Hepatic glycogenosis in childhood: clinical and laboratory findings in 20 patients]. 872 90

Two Maltese puppies with massive hepatomegaly and failure to thrive had isolated deficient glucose-6-phosphatase (G-6-Pase) activity in liver and kidney and pathological findings compatible with GSD-Ia. To identify the mutation, we cloned G-6-Pase canine cDNA by RT-PCR with primers from the murine G-6-Pase gene sequence. The canine G-6-Pase cDNA is 2346 bp, with a 5' untranslated region of 87 bp, a coding region of 1071 bp, and a 3' untranslated region of 1185 bp. The difference between the canine and human sequences is in the 3' untranslated region. A greater than 90% amino acid sequence homology was seen with canine, human, murine, and rat G-6-Pase. G-6-Pase cDNA from affected and control puppies revealed complete homology except at nt position 450, which showed a guanine to cytosine (G to C) transversion resulting in substitution of a methionine by isoleucine at codon 121 (M121I) in all five clones studied. The loss of an NcoI restriction site on genomic DNA amplified with primers flanking the mutation allowed us to prove that affected puppies were homozygous for the mutation and parents were heterozygous carriers. The mutant G-6-Pase cDNA had 15 times less enzyme activity than wild-type cDNA following transient transfection. Northern blot analysis of puppies with GSD-Ia revealed increased G-6-Pase mRNA, compared to normal controls. Increased G-6-Pase mRNA was also seen in normal fasted puppies compared to littermates in the fed state, suggesting that the increased G-6-Pase mRNA is a physiologic response to fasting. This is the first report of a molecularly confirmed naturally occurring animal model of GSD-Ia. The establishment of a breeding colony of this dog strain will facilitate studies on the role of G-6-Pase gene in glucose homeostasis, in pathophysiology of disease, and development of novel therapeutic approaches such as gene therapy.
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PMID:Isolation and nucleotide sequence of canine glucose-6-phosphatase mRNA: identification of mutation in puppies with glycogen storage disease type Ia. 925 82

A 4-year-old German girl was diagnosed as having glycogen storage disease type la and showed no other marked symptoms except hepatomegaly. The glucose-6-phosphatase activity in the liver was approximately 1.5% to 5.0% of normal values, and molecular analysis revealed compound heterozygosity for R83C and the novel mutation N264K. This result indicates that there is a wide clinical variation of glucose-6-phosphatase deficiency. DNA analysis is helpful for confirmation of the diagnosis, as well as establishment of the genotype and phenotype correlation in glycogen storage disease type 1a.
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PMID:A new mutation of the glucose-6-phosphatase gene in a 4-year-old girl with oligosymptomatic glycogen storage disease type 1a. 950 59

The microsomal glucose-6-phosphatase (G6Pase) complex regulates the final step in glucose production from glycogenolysis and gluconeogenesis. Glycogen storage disease type 1c (GSD-1c) results from deficient activity of the phosphate/ pyrophosphate transporter of this complex and is associated with neutropenia as well as hepatomegaly and hypoglycaemia. Using three affected subjects from a single highly consanguineous family, we have used homozygosity mapping to localise the gene responsible for GSD-1c to a 10.2 cM region on 11q23.3-24.2. The maximum lod score was 3.12. GSD-1c is therefore distinct from GSD-1a, which has been shown previously to be caused by mutations in the G6Pase gene on chromosome 17.
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PMID:Localisation of the gene for glycogen storage disease type 1c by homozygosity mapping to 11q. 959 17

Glycogen storage disease type 1 (GSD-1), also known as von Gierke disease, is caused by a deficiency in the activity of the enzyme glucose-6-phosphatase (G6Pase). It is an autosomal recessive disorder characterized by hypoglycemia, hepatomegaly, kidney enlargement, growth retardation, lactic acidemia, hyperlipidemia and hyperuricemia. The disease presents with both clinical and biochemical heterogeneity consistent with the existence of two major subgroups, GSD-1a and GSD-1b, which have been confirmed at the molecular genetic level. GSD-1a, the most prevalent form, is caused by mutations in the G6Pase gene that abolish or greatly reduce enzymatic activity. The gene maps to chromosome 17q21 and encodes a microsomal transmembrane protein. Animal models of GSD-1a exist and are being exploited to delineate the disease more precisely. It has been proposed that GSD-1b is caused by a defect in the microsomal glucose-6-phosphate transporter. The gene responsible for GSD-1b has been mapped to chromosome 11q23 and a cDNA encoding a microsomal transmembrane protein has been identified. The function of this putative GSD-1b protein remains to be determined. These recent developments, along with newly characterized animal models of GSD-1a, are increasing our understanding of the interrelationship between the components of the G6Pase complex and type 1 glycogen storage diseases.
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PMID:Molecular Genetics of Type 1 Glycogen Storage Diseases. 1032 3

We identified a novel mutation (867delA) in the glucose-6-phosphatase gene of two siblings with glycogen storage disease type Ia. Although both siblings share the same mutations, their phenotype regarding adult height and hepatomegaly differs. In glycogen storage disease type Ia, substantial heterogeneity in phenotype is observed. So far, no evidence for a clear genotype-phenotype correlation has been found. Hum Mutat 15:381, 2000.
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PMID:Identification of a novel mutation (867delA) in the glucose-6-phosphatase gene in two siblings with glycogen storage disease type Ia with different phenotypes. 1073 86

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive disorder of glycogen metabolism caused by a deficiency of glucose-6-phosphatase (G6Pase) that is expressed in the liver, kidney, and intestinal mucosa. Clinical manifestations include short stature, hepatomegaly, hypoglycemia, hyperuricemia, and lactic acidemia. To elucidate a spectrum of the G6Pase gene mutations and their frequencies, we analyzed mutations in 51 unrelated Japanese patients with GSD-Ia. The most prevalent mutation was g727t, accounting for 88 of 102 mutant alleles examined, followed by R170X mutation, which accounted for 6 mutant alleles, and R83H mutation which was observed in 3 mutant alleles. In addition, 3 different, novel mutations, IVS1-1g<a, Gly122-to-Asp (G122D) and His179-to-Pro (H179P), were identified. We were able to detect "ectopically" transcribed G6Pase-mRNA in Epstein-Barr virus-transformed lymphoblastoid cells and observed aberrant mRNA splicing associated with the g727t and IVS1-1g<a mutations. To our knowledge, this is the first report that ectopic expression can be utilized for the characterization of GSD-Ia mutations. Our findings suggest that a screening for the g727t, R170X, and R83H mutations by simple DNA-based diagnostic methods can detect 95% of the G6Pase mutant alleles in Japanese patients with GSD-Ia, and remaining mutations can be identified and characterized by the direct sequencing of genomic DNA and/or the analysis of ectopically expressed mRNA. The noninvasive molecular diagnosis for GSD-Ia may ultimately replace the conventional means of enzymatic diagnosis that requires liver biopsy.
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PMID:Glycogen storage disease type Ia: molecular diagnosis of 51 Japanese patients and characterization of splicing mutations by analysis of ectopically transcribed mRNA from lymphoblastoid cells. 1074 7

Type Ib glycogenosis is a rare glycogen storage disorder resulting from a defect in the enzyme, glucose-6-phosphatase microsomal translocase. We report a case of Type Ib glycogenosis in an 18 month-old male child who presented with a history of hypoglycemic seizures and recurrent infections and had a massive hepatomegaly, recurrent hypoglycemia, hyperuricemia, hypertriglyceridemia, neutropenia and fasting lactacidemia which decreased sharply on glucose administration.
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PMID:Type Ib glycogenosis. 1077 88

Glycogen storage disease type Ia (GSD-Ia) is an autosomal recessive disorder of glycogen metabolism caused by glucose-6-phosphatase (G6Pase) deficiency. It is characterized by short stature, hepatomegaly, hypoglycemia, hyperuricemia, and lactic acidemia. Various mutations have been reported in the G6Pase gene (G6PC). However, in Japanese patients, a g727t substitution was found to be the major cause of GSD-Ia, accounting for 20 of 22 mutant alleles [Kajihara et al., 1995], and no other mutations have been found in this population. We analyzed four Japanese GSD-Ia patients and identified three other mutations in addition to the g727t. They included two missense mutations (R83H and P257L) and one nonsense mutation (R170X). Each of the three mutations exhibited markedly decreased G6Pase activity when expressed in COS7 cells. A patient homozygous for R170X showed multiple episodes of profound hypoglycemia associated with convulsions, while P257L was associated with a mild clinical phenotype. The presence of R170X in three unrelated families may implicate that it is another important mutation in the etiology of GSD-Ia in Japanese patients. Thus, the detection of non-g727t mutations is also important in establishing the DNA-based diagnosis of GSD-Ia in this population.
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PMID:Heterogeneous mutations in the glucose-6-phosphatase gene in Japanese patients with glycogen storage disease type Ia. 1079 30

Glycogen storage disease type 1a (GSD 1a) is caused by a deficiency in microsomal glucose-6-phosphatase (G6Pase). A variant (GSD 1b) is caused by a defect in the transport of glucose-6-phosphate (G6P) into the microsome and is associated with chronic neutropenia and neutrophil dysfunction. Mutually exclusive mutations in the G6Pase gene and the G6P transport gene establish GSD la and GSD 1b as independent molecular processes and are consistent with a multicomponent translocase catalytic model. A modified translocase/catalytic unit model based on biochemical data in a G6Pase knockout mouse has also been proposed for G6Pase catalysis. This model suggests coupling of G6Pase activity and G6P transport. A 5-mo-old girl with hypoglycemia, hepatomegaly, and lactic acidemia was diagnosed with GSD 1a. She also developed neutropenia, neutrophil dysfunction, and recurrent infections characteristic of GSD 1b. Homozygous G188R mutations of the G6Pase gene were identified, but no mutations in the G6P translocase gene were found. We have subsequently identified a sibling and two unrelated patients with similar genotypic/phenotypic characteristics. The unusual association of neutrophil abnormalities in patients with homozygous G188R mutations in the G6Pase gene supports a modified translocase/catalytic unit model.
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PMID:Glucose-6-phosphatase mutation G188R confers an atypical glycogen storage disease type 1b phenotype. 1096 Apr 98


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