Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mucopolysaccharidoses are caused by inherited deficiencies of lysosomal enzymes involved in the degradative pathway of glycosaminoglycans. Lysosomal storage leads to cellular and organ dysfunction, including mental retardation. Storage lesions are found throughout the diseased brain, but little is known about the cellular and molecular mechanisms that underlie brain dysfunction. In the mouse model of mucopolysaccharidosis VII, we found that specific regions of the brain are vulnerable to neurodegeneration, characterized by the presence of ubiquitin inclusions, neurofilament inclusions, and reactive astrogliosis. The pathological lesions were found predominantly in the hippocampus and cerebral cortex, and they increased progressively with age. Treatment with a recombinant viral vector to correct the enzymatic defect quantitatively reversed the neurodegenerative lesions in targeted regions to normal levels.
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PMID:Selective neurodegeneration in murine mucopolysaccharidosis VII is progressive and reversible. 1244 30

Systemic injection of an adenovirus vector into adult mice resulted in pathological improvements in multiple visceral organs of mice with mucopolysaccharidosis VII; however, no therapeutic efficacy was observed for mental retardation, skeletal deformities, corneal clouding, and retinal degeneration. In this study, an adenovirus vector expressing human beta-glucuronidase was injected into mice with mucopolysaccharidosis VII within 24 h of birth, and therapeutic efficacy was evaluated. In the brains of the mice, more than 20% of GUSB activity was maintained for at least 20 weeks after birth, and histopathological analysis showed no obvious lysosomal storage. Furthermore, no vacuolated cells were detected in corneal stroma and retinal pigment epithelium in the eyes of the mice treated in the neonatal period, while pathological improvement was not observed in adult MPSVII mice that received similar treatments. The treated mice also lacked characteristic facial skeletal deformities, and radiographic analysis demonstrated that their facial and cranial bones were morphologically normal. These results indicate that a single systemic adenovirus injection in the neonatal period could prevent the progression of mental retardation, corneal clouding, retinal degeneration, and skeletal deformities, all of which are frequently observed clinical manifestations and difficult to treat in adulthood.
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PMID:Long-term normalization in the central nervous system, ocular manifestations, and skeletal deformities by a single systemic adenovirus injection into neonatal mice with mucopolysaccharidosis VII. 1260 95

Mucopolysaccharidosis type VII or Sly syndrome is an autosomal recessive disorder of glycosaminoglycan storage leading to variable clinical symptoms, such as hepatosplenomegaly, bone deformities, hearing loss, corneal opacities, mental retardation, and hydrops fetalis in affected individuals. The disease is caused by approximately 40 different mutations in the beta-glucuronidase gene. Detection of the most common mutation L176F by single-strand conformation polymorphism (SSCP) was not always successful. Although DNA sequencing followed by PCR amplification can easily detect this mutation, accessibility to a DNA sequencer or useful reagents in the sequencing procedure is not readily available in many countries. A PCR-based restriction fragment length polymorphism (RFLP) developed in this report would allow rapid and easier detection of this mutation for screening new patients or neonates of heterozygous parents. Analysis of intragenic polymorphic sites in the L176F patients identified two distinct alleles; the predominant one probably originated in Spain.
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PMID:PCR-based restriction fragment length polymorphism and haplotype of the most common mutation L176F in the beta-glucuronidase gene. 1739 95

Lysosomal storage disorders constitute a large group of genetic diseases, many of which are characterized by mental retardation and other neurologic symptoms. The mechanisms of neural dysfunction remain poorly understood. Because neural progenitor cells (NPCs) are fundamentally important to normal brain development and function, we investigated NPC properties in a canine model of mucopolysaccharidosis VII (MPS VII). MPS VII is a lysosomal storage disorder characterized by defects in the catabolism of glycosaminoglycans. NPCs were isolated from the olfactory bulb, cerebellum, and striatal subventricular zone of normal and MPS VII (beta-glucuronidase-deficient) postnatal dog brains. Canine NPCs (cNPCs) from normal and MPS VII brains had similar growth curves, but cerebellar-derived cNPCs grew significantly slower than those derived from other regions. In differentiation assays, MPS VII cNPCs from the striatal subventricular zone and cerebellum generated fewer mature neuronal and/or glial cells than normal, and MPS VII olfactory bulb-derived cNPCs retained significantly more phenotypically immature cells. These differences were only present at the earliest time point after isolation; at later passages, there were no differences attributable to genotype. The data suggest that MPS VII cNPCs respond differently to developmental cues in vivo, probably because of the diseased neural microenvironment rather than intrinsic cellular deficits.
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PMID:Abnormalities in neural progenitor cells in a dog model of lysosomal storage disease. 1788 20

Mucopolysaccharidosis VII (MPS VII; Sly syndrome) is an autosomal recessive disorder caused by a deficiency of beta-glucuronidase (GUS, EC 3.2.1.31; GUSB). GUS is required to degrade glycosaminoglycans (GAGs), including heparan sulfate (HS), dermatan sulfate (DS), and chondroitin-4,6-sulfate (CS). Accumulation of undegraded GAGs in lysosomes of affected tissues leads to mental retardation, short stature, hepatosplenomegaly, bone dysplasia, and hydrops fetalis. We summarize information on the 49 unique, disease-causing mutations determined so far in the GUS gene, including nine novel mutations (eight missense and one splice-site). This heterogeneity in GUS gene mutations contributes to the extensive clinical variability among patients with MPS VII. One pseudodeficiency allele, one polymorphism causing an amino acid change, and one silent variant in the coding region are also described. Among the 103 analyzed mutant alleles, missense mutations accounted for 78.6%; nonsense mutations, 12.6%; deletions, 5.8%; and splice-site mutations, 2.9%. Transitional mutations at CpG dinucleotides made up 40.8% of all the described mutations. The five most frequent mutations (accounting for 44/103 alleles) were exonic point mutations, p.L176F, p.R357X, p.P408S, p.P415L, and p.A619 V. Genotype/phenotype correlation was attempted by correlating the effects of certain missense mutations or enzyme activity and stability within phenotypes. These were in turn correlated with the location of the mutation in the tertiary structure of GUS. A total of seven murine, one feline, and one canine model of MPS VII have been characterized for phenotype and genotype.
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PMID:Mutations and polymorphisms in GUSB gene in mucopolysaccharidosis VII (Sly Syndrome). 1922 84

Mucopolysaccharidoses are autosomal and recessive lysosomal storage disorders caused by the deficiency of a lysosomal enzyme involved in glycosaminoglycan catabolism. The Sanfilippo type A disease (MPS III A) results from sulfamidase deficiency, which leads to accumulation of heparan sulfate, whereas Sly disease (MPS VII) results from beta-glucuronidase deficiency, leading to accumulation of heparan, dermatan, and chondroitin sulfates. These syndromes are characterized by severe central nervous system degeneration, resulting in progressive mental retardation, and fatality occurs in severely affected children. To date, no effective treatment is available except for bone marrow transplantation in specific cases. Recently, the use of genistein, an isoflavone that inhibits glycosaminoglycans synthesis, has been tested as substrate reduction therapy for neuronopathic forms of these diseases.We tested five natural analogs to genistein in human fibroblasts from both Sanfilippo A and Sly patients. Four molecules were as efficient as genistein in decreasing glycosaminoglycan accumulation. Moreover, a combination of several isoflavones was more efficient than one single isoflavone, suggesting a synergistic effect. These preliminary data may offer new perspectives for treating Sly and Sanfilippo A diseases and could be relevant to other neurological forms of mucopolysaccharidoses.
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PMID:Storage correction in cells of patients suffering from mucopolysaccharidoses types IIIA and VII after treatment with genistein and other isoflavones. 2008 60

The mucopolysaccharidoses (MPSs) are a group of rare, inherited lysosomal storage disorders that are clinically characterized by abnormalities in multiple organ systems and reduced life expectancy. The MPSs are heterogeneous, progressive disorders. Patients typically appear normal at birth, but during early childhood they experience the onset of clinical disease, including skeletal, joint, airway and cardiac involvement, hearing and vision impairment, and mental retardation in the severe forms of MPS I, MPS II and MPS VII and all subtypes of MPS III. There are two treatment options for patients with MPS that are directed at the underlying pathophysiology: haematopoietic stem cell transplantation, which is useful for selected patients, and recombinant i.v. enzyme replacement therapy, which is available for MPS I, II and VI. Early diagnosis and treatment can improve patient outcomes and may reduce the disease burden on patients and caregivers. As skeletal and joint abnormalities are characteristic of many patients with MPS, rheumatologists are positioned to recognize the features of the disease and to facilitate early diagnosis and referral. In this overview, the clinical features of the MPS disorders and a brief review of treatment options will be presented in order to aid the rheumatologist in recognizing the features of these rare genetic disorders.
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PMID:Overview of the mucopolysaccharidoses. 2221 Jun 69


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