Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA analysis was carried out in 113 patients of 103 families. In 58 families (55%) deletions were found using different cDNA probes. The attempt of studying the correlation between mental retardation in patients and the exon deletions was made. Dystrophin was evaluated in 80 patients including 12 affected females. One girl had chromosomal translocation X;22 and was a true DMD case. An unusual pedigree typical of X-linked transmission with affected subjects showing clinical features of DMD but with normally expressed dystrophin is presented. Owing to DNA and dystrophin analysis the correct diagnosis in some doubtful cases of muscular dystrophies could be established and some unusual pedigrees detected.
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PMID:Interrelationship between gene, its product and phenotype in Duchenne and Becker muscular dystrophy. 831 63

Xp21 microdeletion syndrome is associated with variable size Xp21 deletions that usually include the glycerol kinase locus. The clinical phenotypes we studied in this chromosome region include: Xpter - Aland Island eye disease (AIED) -adrenal hypoplasia (AH) -glycerol kinase (GKD) -Duchenne muscular dystrophy (DMD) -retinitis pigmentosa (RP) -ornithine transcarbamylase (OTC) -centromere. In a compilation of 18 individuals in 14 families with the AH, GKD, and DMD loci deleted, 17 were male and all were developmentally delayed. In contrast, we report mentally retarded female carriers in two Xp21 deletion syndrome families with DMD, GKD, and AH in affected males. In the first family with normal karyotypes, a submicroscopic deletion was associated with DMD in the retarded male and with retardation in carrier females. In the second family an X chromosome with a cytogenetically deleted Xp21 distal to the OTC and RP genes segregated in the affected male and retarded female carriers. DNA analysis at the DMD locus verified the cytogenetic findings. This report of mental retardation in otherwise asymptomatic female carriers of Xp21 deletion classifies one form of mental retardation in females.
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PMID:Mental retardation locus in Xp21 chromosome microdeletion. 835 5

The dystrophin gene was analyzed in 59 Japanese patients with Duchenne muscular dystrophy (DMD) from 48 unrelated families, including 11 pairs of siblings, and three patients with Becker muscular dystrophy (BMD) from two unrelated families, including one pair of siblings. The relationship between the type of gene abnormality and clinical symptoms was examined. Twenty-seven of 50 (54.0%) unrelated DMD or BMD patients were found to have partial deletions, and five (10%) appeared to have partial duplications in the dystrophin gene. Nine DMD patients, including three pairs of siblings, showed mental retardation, the existence of which was coincident in each pair of siblings, but deletion of an identical exon was not always related to mental retardation in unrelated patients.
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PMID:Detection of partial deletion and partial duplication of dystrophin gene in Japanese patients with Duchenne or Becker muscular dystrophy. 835 41

Alpha- and beta-dystroglycan (alpha- and beta-DG) are members of a dystrophin-associated glycoprotein complex (DGC) in skeletal muscle which binds to agrin and laminin, and has been postulated to be involved in myoneural snyapse formation. The absence of functional dystrophin in Duchenne muscular dystrophy (DMD) and in one of its animal models, the mdx mouse, leads to a reduction of alpha- and beta-DG in muscle, and is often associated with mental retardation and abnormal retinal synaptic transmission in DMD. Using immunohistochemistry, we find that alpha- and beta-DG are expressed in the outer plexiform layer of both wild type and mdx retina, where both dystrophin and dystrophin-related protein (DRP), but not laminin are present. In situ hybridization identifies two neuronal populations, photoreceptors and retinal ganglion cells, that express DG mRNA. Alpha- and beta-DG are also expressed in the inner limiting membrane and around blood vessels where they colocalize with laminin and DRP. Western blot analysis revealed the expression of several dystrophin isoforms in wild type and mdx retina, possibly explaining the unaltered expression of alpha- and beta-dystroglycan in the mdx central nervous system (CNS). Our results support the hypothesis that alpha- and beta-DG can interact with dystrophin and DRP in the CNS and perform functions analogous to those of the DGC in muscle.
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PMID:Dystroglycan expression in the wild type and mdx mouse neural retina: synaptic colocalization with dystrophin, dystrophin-related protein but not laminin. 856 39

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder primarily affecting young boys, often causing mental retardation in addition to the well-known progressive muscular weakness. Normal dystrophin expression is lacking in skeletal muscle and the CNS of both DMD children and the mdx mouse model. To date, 31P-magnetic resonance spectroscopy (MRS) has shown in vivo several abnormalities within skeletal muscle of mdx mice and DMD boys. In this study, we determined whether similar abnormalities occur in mdx brain in vivo by using 31P-MRS in addition to metabolite and enzyme analysis to study cerebral metabolism. An increased inorganic phosphate (P(i))/phosphocreatine (PCr) and pH was found in vivo for mdx brain compared with controls, and biochemical analysis showed a reduction in total creatine, an increased extracellular and decreased intracellular volume in mdx brain. No differences were found in any glycolytic or mitochondrial maximal enzyme activities. These changes are discussed with respect to the biochemical changes found in muscle from DMD patients and mdx mice. It is proposed that these biochemical changes may be a factor in the reduced cognitive capacity of mdx mice and some DMD children.
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PMID:Brain metabolism is abnormal in the mdx model of Duchenne muscular dystrophy. 867 81

In order to characterize the nature of mutations occurring in non-deleted Duchenne (DMD) and Becker muscular dystrophy (BMD) affected males, a total of 40 unrelated Italian patients was studied for the presence of point mutations within the muscle-specific regulatory region of the dystrophin gene. We decided to investigate the dystrophin promoter sequences because nucleotide variations in these regions could impair the expression of the gene and be the underlying molecular defect in some forms of the disease. In four patients suffering from mental retardation, the brain promoter region was also studied. To screen for point mutations, we applied molecular analysis by parallel denaturing gradient gel electrophoresis (DGGE). No sequence alterations were found in either the muscle or the brain promoters, suggesting that mutations in these regions do not represent a common mechanism of mutation in DMD/BMD.
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PMID:Mutational analysis of muscle and brain specific promoter regions of dystrophin gene in DMD/BMD Italian patients by denaturing gradient gel electrophoresis (DGGE). 880 15

X-linked non-specific mental retardation (MRX) is a heterogeneous condition in which mental retardation (MR) appears to be the only consistent manifestation. The genetic and phenotypic heterogeneity exclude any possibility of pooling families and, therefore, of fine-mapping the related disease genes. In order to identify genomic critical regions involved in the MRX condition assigned to Xp21.3-22.1 region, we have implemented the PCR screening of non fragile X MR patients for the presence of deletions in this region. The amplification by PCR of 12 markers located between POLA and DXS704 using genomic DNA from 192 MR males led to the identification, in a 9 year old mentally retarded boy, of a microdeletion which extends from DXS1202 to DXS1065. None of the known genes, POLA, MAGE genes cluster, DAX1, GK and DMD, that map in the Xp21.3-22.1 region is affected by this deletion. This approach, which could easily be applied to several other MRX loci, allowed not only a confirmation of the presence of a potential locus in Xp21.3-22.1 involved in non-specific mental retardation, but also a better definition of the genomic critical region corresponding to this locus.
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PMID:Identification by STS PCR screening of a microdeletion in Xp21.3-22.1 associated with non-specific mental retardation. 881 33

We reevaluated a family previously described as having nonspecific X-linked mental retardation (XLMR) by Snyder and Robinson [1969: Clin Pediatr 8:669-674] (MIM 309583). Clinical and DNA studies were conducted on 17 relatives, including 6 males with mild-to-moderate mental retardation, 3 carrier females, and 8 normal males. In contrast to the normal appearance and minimal clinical findings reported 22 years ago, affected males were found to have a characteristic set of clinical findings. These developed gradually over the first 2 decades, and included thin body build with diminished muscle mass, osteoporosis and kyphoscoliosis, slight facial asymmetry with a prominent lower lip, nasal speech, high narrow or cleft plate, and long great toes. Carrier females were clinically normal. Multipoint linkage analysis indicated linkage to markers distal to the 3' end of DMD (DXS41 and DXS989), with a maximal lod score of 4.7. On the basis of these findings, this entity is redefined as XLMR syndrome.
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PMID:X-linked mental retardation with thin habitus, osteoporosis, and kyphoscoliosis: linkage to Xp21.3-p22.12. 882 48

Two genes responsible for a nonspecific form of X-linked mental retardation (MRX28 and MRX33) were localized by linkage analysis with 40 highly polymorphic DNA markers situated along the entire the X chromosome. In family 1, the gene could be mapped within a 14-cM interval at Xq28, distal to the recombining marker DXS1113 (MRX28). The maximum LOD score was 2.75, with DXS52 at phi = .0. In family 2, the gene was localized within a 30-cM interval at Xp11.4-22.12 between the recombining markers DXS365 and MAOB, including the DMD gene (MRX33). Maximum LOD scores of 2.82 were obtained with markers DMD-STR49, DMD-DysII, CYBB, and DXS1068.
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PMID:Regional localization of two MRX genes to Xq28 (MRX28) and to Xp11.4-Xp22.12 (MRX33). 882 62

Duchenne muscular dystrophy (DMD) is a progressive degenerative lethal muscle disease. A significant proportion of DMD affected children suffer also from mental retardation. The rod shaped protein, dystrophin, which is absent from or defective in the muscle of DMD patients, binds to a number of membrane associated proteins (known collectively as dystrophin associated proteins [DAPs]). The levels of DAPs is greatly reduced in the muscle of DMD patients and mdx mice, which lack dystrophin. In addition to dystrophin isoforms, the DMD gene codes also for several smaller proteins. One of the small proteins, Dp71, is expressed in most or all non-muscle tissues and is the major DMD gene product in the brain. The function of the small DMD gene products is unknown. Here we show that mutant mice which do not express the smaller non-muscle products of the DMD gene have a reduced level of DAPs in their brain. This suggests that Dp71 is important for the formation and/or stabilization of a DAPs complex in brain.
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PMID:Reduced levels of dystrophin associated proteins in the brains of mice deficient for Dp71. 887 69


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