Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Muscle eye brain disease (MEB) and Fukuyama congenital muscular dystrophy (FCMD) are congenital muscular dystrophies with associated, similar brain malformations. The FCMD gene, fukutin, shares some homology with fringe-like glycosyltransferases, and the MEB gene, POMGnT1, seems to be a new glycosyltransferase. Here we show, in both MEB and FCMD patients, that alpha-dystroglycan is expressed at the muscle membrane, but similar hypoglycosylation in the diseases directly abolishes binding activity of dystroglycan for the ligands laminin, neurexin and agrin. We show that this post-translational biochemical and functional disruption of alpha-dystroglycan is recapitulated in the muscle and central nervous system of mutant myodystrophy (myd) mice. We demonstrate that myd mice have abnormal neuronal migration in cerebral cortex, cerebellum and hippocampus, and show disruption of the basal lamina. In addition, myd mice reveal that dystroglycan targets proteins to functional sites in brain through its interactions with extracellular matrix proteins. These results suggest that at least three distinct mammalian genes function within a convergent post-translational processing pathway during the biosynthesis of dystroglycan, and that abnormal dystroglycan-ligand interactions underlie the pathogenic mechanism of muscular dystrophy with brain abnormalities.
 ...
PMID:Post-translational disruption of dystroglycan-ligand interactions in congenital muscular dystrophies. 1214 May 40

Fukuyama-type congenital muscular dystrophy (FCMD) is a severe autosomal-recessive muscular dystrophy accompanied by brain malformation. Previously, we identified the gene responsible for FCMD through positional cloning. Here we report the isolation of its murine ortholog, Fcmd. The predicted amino acid sequence of murine fukutin protein encoded by Fcmd is 90% identical to that of its human counterpart. Radiation hybrid mapping localized the gene to 2.02 cR telomeric to D4Mit272 on chromosome 4. Northern blot analysis revealed ubiquitous expression of Fcmd in adult mouse tissues. Through in situ hybridization, we observed a wide distribution of Fcmd expression throughout embryonic development, most predominantly in the central and peripheral nervous systems. We also detected high Fcmd expression in the ventricular zone of proliferating neurons at 13.5 days post-coitum. Brain malformation in FCMD patients is thought to result from defective neuronal migration. Our data suggest that neuronally expressed Fcmd is likely to be important in the development of normal brain structure.
 ...
PMID:Isolation and characterization of the mouse ortholog of the Fukuyama-type congenital muscular dystrophy gene. 1240 65

Two forms of congenital muscular dystrophy (CMD), Fukuyama CMD and CMD type 1C (MDC1C) are caused by mutations in the genes encoding two putative glycosyltransferases, fukutin and fukutin-related protein (FKRP). Additionally, mutations in the FKRP gene also cause limb-girdle muscular dystrophy type 2I (LGMD2I), a considerably milder allelic variant than MDC1C. All of these diseases are associated with secondary changes in muscle alpha-dystroglycan expression. To elucidate the function of FKRP and fukutin and examine the effects of MDC1C patient mutations, we have determined the mechanism for the subcellular location of each protein. FKRP and fukutin are targeted to the medial-Golgi apparatus through their N-termini and transmembrane domains. Overexpression of FKRP in CHO cells alters the post-translational processing of alpha- and beta-dystroglycan inhibiting maturation of the two isoforms. Mutations in the DxD motif in the putative active site of the protein or in the Golgi-targeting sequence, which cause FKRP to be inefficiently trafficked to the Golgi apparatus, did not alter dystroglycan processing in vitro. The P448L mutation in FKRP that causes congenital muscular dystrophy changes a conserved amino acid resulting in the mislocalization of the mutant protein in the cell that is unable to alter dystroglycan processing. Our data show that FKRP and fukutin are Golgi-resident proteins and that FKRP is required for the post-translational modification of dystroglycan. Aberrant processing of dystroglycan caused by a mislocalized FKRP mutant could be a novel mechanism that causes congenital muscular dystrophy.
 ...
PMID:Functional requirements for fukutin-related protein in the Golgi apparatus. 1247 Oct 58

Fukuyama-type congenital muscular dystrophy (FCMD), Walker-Warburg syndrome, and muscle-eye-brain disease are clinically similar autosomal recessive disorders characterized by congenital muscular dystrophy, cobblestone lissencephaly, and eye anomalies. FCMD is frequent in Japan, but no FCMD patient with confirmed fukutin gene mutations has been identified in a non-Japanese population. Here, we describe a Turkish CMD patient with severe brain and eye anomalies. Sequence analysis of the patient's DNA identified a homozygous 1bp insertion mutation in exon 5 of the fukutin gene. To our knowledge, this is the first case worldwide in which a fukutin mutation has been found outside the Japanese population. This report emphasizes the importance of considering fukutin mutations for diagnostic purposes outside of Japan.
 ...
PMID:A new mutation of the fukutin gene in a non-Japanese patient. 1260 8

The gene mutated in the myodystrophy mouse, a model of muscular dystrophy, encodes a putative glycosyltransferase, Large. Mutations in genes encoding proteins thought to be involved in glycosylation have now been identified in six human forms of muscular dystrophy. Hereditary inclusion body myopathy and Nonaka myopathy result from defects in sialic acid production. Two forms of congenital muscular dystrophy, Fukuyama-type and MDC1C, result from mutations in members of the fukutin family. MDC1C and limb girdle muscular dystrophy type 2I are allelic, as they are both associated with mutations in the FKRP gene. Mutations in POMGnT, which encodes an enzyme involved in the synthesis of O-mannosyl glycans, result in muscle-eye-brain disease--another congenital form of muscular dystrophy. Abnormal alpha-dystroglycan has been reported in the myodystrophy mouse, and in the congenital and limb girdle muscular dystrophies. Recent data have shown that there is altered glycosylation of the protein and that this reduces its ability to bind to extracellular matrix ligands such as laminin and agrin.
 ...
PMID:Glycosylation defects in inherited muscle disease. 1267 90

Fukuyama-type congenital muscular dystrophy (FCMD), one of the most common autosomal-recessive disorders in Japan, is characterized by congenital muscular dystrophy associated with brain malformation due to a defect during neuronal migration. Through positional cloning, we previously identified the gene for FCMD, which encodes the fukutin protein. Here we report that chimeric mice generated using embryonic stem cells targeted for both fukutin alleles develop severe muscular dystrophy, with the selective deficiency of alpha-dystroglycan and its laminin-binding activity. In addition, these mice showed laminar disorganization of the cortical structures in the brain with impaired laminin assembly, focal interhemispheric fusion, and hippocampal and cerebellar dysgenesis. Further, chimeric mice showed anomaly of the lens, loss of laminar structure in the retina, and retinal detachment. These results indicate that fukutin is necessary for the maintenance of muscle integrity, cortical histiogenesis, and normal ocular development and suggest the functional linkage between fukutin and alpha-dystroglycan.
 ...
PMID:Fukutin is required for maintenance of muscle integrity, cortical histiogenesis and normal eye development. 1278 52

Dystroglycan is a key complex between basal lamina laminin, extracellularly and membrano-cytoskeleton, intracellularly. The damage of this linkage is turned out to cause muscular dystrophies. Dystroglycan knockout is lethal. Dystroglycan-associated intracellular proteins such as dystrophin, dystrobrevin, sarcoglycans, plectin and caveolin-3 are responsible for causing severe (Duchenne type) and moderate forms (Becker, LGMDs). Laminin, dystroglycan-binding extracellular protein, is deficient in the most severe form of congenital muscular dystrophy with normal intelligence and eye. Recently, a remarkable progress is made in most severe forms of congenital muscular dystrophy with anomalies of brain and eye such as Fukuyama type (Japan) and muscle-eye-brain disease (Finland). The gene product for Fukuyama type, fukutin, belongs to a family of glycosylation enzymes in bacteria and yeast. Since alpha-dystroglycan contains 14-15 o-glycans, ser/thr-mannose 2-1 GlcNAc 4-1 Gal 3-2 Sial in the middle third mucin-domain and the sial-o-glycan is essential for laminin-binding, and since alpha-dystroglycan is defective in Fukuyama type sarcolemma with anti both sugar moiety- and peptide-antidodies, defective fukutin causes incomplete o-glycosylation of alpha-dystroglycan. In '02, it is clarified that a glycosylation enzyme, POMGnT1 which modifies GlcNAc onto ser/thr-mannose, is defective in 6 MEB patients. The loss of the enzyme activity is turned out to lose alpha-dystroglycan from sarcolemma of MEB. These data strongly suggests that o-glycosylation defect of alpha-dystroglycan causes the most severe congenital muscular dystrophy such as Fukuyama type, MEB and Walker Warburg syndrome.
 ...
PMID:[Dystroglycan linkage and muscular dystrophy]. 1278 74

Fukuyama-type congenital muscular dystrophy (FCMD), Walker-Warburg syndrome (WWS), and muscle-eye-brain (MEB) disease are clinically similar autosomal recessive disorders characterized by congenital muscular dystrophy, lissencephaly, and eye anomalies. Through positional cloning, we identified the gene for FCMD and MEB, which encodes the fukutin protein and the protein O-linked mannose beta1, 2-N-acetylglucosaminy ltransferase (POMGnT1), respectively. Recent studies have revealed that posttranslational modification of alpha-dystroglycan is associated with these congenital muscular dystrophies with brain malformations. In this review Fukuyama-type congenital muscular dystrophy (FCMD), other CMDs with brain malformations, and their relation with alpha-dystroglycan are discussed.
 ...
PMID:Fukuyama-type congenital muscular dystrophy (FCMD) and alpha-dystroglycanopathy. 1289 68

Recently, post-translational modification of proteins has been defined as a new area of focus for muscular dystrophy research by the identification of a group of disease genes that encode known or putative glycosylation enzymes. Walker-Warburg Syndrome (WWS) and muscle-eye-brain disease (MEB) are caused by mutations in two genes involved in O-mannosylation, POMT1 and POMGnT1, respectively. Fukuyama muscular dystrophy (FCMD) is due to mutations in fukutin, a putative phospholigand transferase. Congenital muscular dystrophy type 1C and limb girdle muscular dystrophy type 2I are allelic, both being due to mutations in the gene-encoding fukutin-related protein (FKRP). Finally, the causative gene in the myodystrophy (myd) mouse is a putative bifunctional glycosyltransferase (Large). WWS, MEB, FCMD and the myd mouse are also associated with neuronal migration abnormalities (often type II lissencephaly) and ocular or retinal defects. A deficiency in post-translational modification of alpha-dystroglycan is a common feature of all these muscular dystrophies and is thought to involve O-glycosylation pathways. This abnormally modified alpha-dystroglycan is deficient in binding to extracellular matrix ligands, including laminin and agrin. Selective deletion of dystroglycan in the central nervous system (CNS) produces brain abnormalities with striking similarities to WWS, MEB, FCMD and the myd mouse. Thus, impaired dystroglycan function is strongly implicated in these diseases. However, it is unlikely that these five glycosylation enzymes only have a role in glycosylation of alpha-dystroglycan and it is important that other protein targets are identified.
 ...
PMID:Glycosylation defects: a new mechanism for muscular dystrophy? 1292 72

The congenital muscular dystrophies (CMD) are a heterogeneous group of autosomal recessive disorders. A new pathomechanism has recently been identified in a group of these disorders in which known or putative glycosyltransferases are defective. Common to all these conditions is the hypoglycosylation of alpha-dystroglycan. Fukuyama CMD, muscle-eye-brain disease and Walker-Warburg syndrome, each associated with eye abnormalities and neuronal migration defects, result from mutations in fukutin, POMGnT1 and POMT1, respectively, while mutations in the fukutin-related protein (FKRP) gene cause congenital muscular dystrophy 1C, typically lacking brain involvement. Another putative glycosyltransferase, Large, is mutated in the myodystrophy mouse. The human homologue of this gene is therefore a strong candidate for involvement in novel forms of muscular dystrophy. We studied 36 patients with muscular dystrophy and either mental retardation, structural brain changes or abnormal alpha-dystroglycan immunolabelling, unlinked to any reported CMD loci. Linkage analysis in seven informative families excluded involvement of LARGE but sequencing of this gene in the remaining 29 families identified one patient with a G1525A (Glu509Lys) missense mutation and a 1 bp insertion, 1999insT. This 17-year-old girl presented with congenital muscular dystrophy, profound mental retardation, white matter changes and subtle structural abnormalities on brain MRI. Her skeletal muscle biopsy showed reduced immunolabelling of alpha-dystroglycan. Immunoblotting with an antibody to a glycosylated epitope demonstrated a reduced molecular weight form of alpha-dystroglycan that retained some laminin binding activity. This is the first description of mutations in the human LARGE gene and we propose to name this new disorder MDC1D.
 ...
PMID:Mutations in the human LARGE gene cause MDC1D, a novel form of congenital muscular dystrophy with severe mental retardation and abnormal glycosylation of alpha-dystroglycan. 1296 29


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