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)

A 21-year-old man with childhood-onset mental retardation, non-obstructive hypertrophic cardiomyopathy, and vacuolar myopathy is presented. A histopathological study of biopsied skeletal muscle showed lysosomal glycogen storage mimicking acid maltase deficiency, but biochemical analysis showed normal acid alpha-glucosidase activity. Glycogenosomes were also recognized in endothelial cells on electronmicroscopic examination of biopsied skeletal muscle. Magnetic resonance imaging (MRI) findings in the head revealed the involvement of the central nervous system. This is a new type of lysosomal glycogen storage disease with multisystemic involvement. The specific biochemical defect in this disorder remains to be elucidated.
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PMID:Cardiomyopathy, mental retardation, and autophagic vacuolar myopathy. Abnormal MRI findings in the head. 179 62

Two unrelated 16-year-old boys had mental retardation, cardiomegaly, and proximal myopathy. One also had hepatomegaly. Histochemistry and electronmicroscopy of muscle biopsies showed lysosomal glycogen storage resembling acid maltase deficiency. Biochemical studies of skeletal muscle showed increased content of glycogen of normal structure; acid alpha-glucosidase activity in both urine and muscle was normal. Other enzymes of glycogen metabolism were also normal. The cause of this apparently generalized glycogenosis with no demonstrable enzyme defect is unknown.
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PMID:Lysosomal glycogen storage disease with normal acid maltase. 645 Mar 34

Glycogen storage disease with normal acid maltase first reported by Danon et al. was characterized clinically by mental retardation, cardiomyopathy, and proximal myopathy. Since the first report, 17 patients have been reported including 5 patients from Japan. In this paper we described a 26-year-old man who had dilatated cardiomyopathy with a pacemaker implanted at age 22 years. He was admitted to our hospital complaining of easy fatigability in February 1992. Neurological findings showed that he had mental retardation. Serum CK, GOT, GPT and aldolase levels were elevated. Histopathological study of biopsied skeletal muscle showed intracytoplasmic vacuoles with increased acid phosphatase and slightly increased PAS positive material. Electron microscopic study revealed numerous glycogenosomes (autophagic vacuoles containing glycogen). These pathological findings were similar to acid maltase deficiency, but activities of carbohydrate metabolic enzyme including acid maltase activity were normal in the biopsied muscle. From these results, he was diagnosed as having glycogen storage disease with normal acid maltase. We also found abnormal platelet function and glycogen accumulation in the platelets, which have not been previously described. The disease is probably a systemic disorder affecting not only skeletal and cardiac muscles, but platelets.
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PMID:[A case of glycogen storage disease with normal acid maltase accompanied with the abnormal platelet function]. 799 92

A 13-year-old boy with mental retardation developed idiopathic cardiomyopathy and glycogen storage myopathy, but with normal lysosomal enzyme activities, consistent with a syndrome of lysosomal glycogen storage disease with normal acid maltase coined by Danon et al (1981). He was in good health except for WPW syndrome diagnosed at 7 years of age. He had heart murmur with abnormal ECG, elevated serum GOT, GPT, LDH, CK and aldolase levels. An echocardiogram showed obstructive hypertrophic cardiomyopathy. Lysosomal enzyme activities including acid alpha-glucosidase in fibroblasts were within normal limits. In the biopsied biceps brachii muscle, there was a mild variation in fiber size. An approximately 10 percent of myofibers had tiny vacuoles which contained periodic acid Schiff positive granules and were slightly high in acid phosphatase activity. The vacuoles were encircled by membranes with high neuron specific enolase (NSE) and acethylcholin-esterase (AchE) activities. On electron microscopy, numerous autophagic vacuoles scavenging glycogen granules were recognized as seen in acid maltase deficiency. Because the vacuolar membranes were high in NSE and AchE activities, lysosomal membrane formation from the cell membrane may be defective. When one has a patient with mild to moderate mental retardation, idiopathic hypertrophic cardiomyopathy and high serum CK level, muscle biopsy must be performed to rule out the present disorder.
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PMID:[A patient with lysosomal glycogen storage disease with normal acid maltase]. 839 37

Lysosomal glycogen storage disease without acid maltase deficiency is characterized by the triad of clinical manifestations (hypertrophic cardiomyopathy), mental retardation, and mild myopathy), morphologic findings (glycogen storage, glycogenosomes, and autophagic vacuoles), and normal glycolytic enzyme activities. Though most of the patients suffering from the triad were males, family studies often revealed female patients with only cardiomyopathy. So far 27 cases have been reported. The cardiac involvement is progressive and fatal and as severe in females as in males. Many patients of both sexes die in their youth, unexpectedly, because of cardiac failure. The specific biochemical defect causing this disease remains unknown. From abnormal lectin staining patterns on the membrane and preclinical morphologic changes in biopsied skeletal muscle, membranous abnormality is suspected in this disease.
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PMID:[Lysosomal glycogen storage disease without acid maltase deficiency]. 857 57

We describe a boy with an early lethal hypertrophic vacuolar cardiomyopathy of neonatal onset. Abnormal intra- and extralysosomal glycogen storage disease was demonstrated in heart and skeletal muscles. Glycogen content was twice the normal in muscles and over 3-fold the normal in the heart. In this organ, over 50% of the intracellular space was occupied by glycogen and possibly oligosaccharides, as demonstrated by the quantitative morphometric analysis of electron micrographs. The activity of acid alpha-glucosidase was increased in the heart, skeletal muscles, and liver, but was normal in leukocytes. A review of the 11 previously published pedigrees of lysosomal glycogen storage disease with normal in vitro alpha-glucosidase activity allows the delineation of three clinical entities: juvenile and neonatal pseudo-Pompe diseases and partial Pompe disease. Partial Pompe disease, due to the tissue-specific absence of acid alpha-glucosidase, was observed in a single patient. The most common form is the late-onset pseudo-Pompe disease, which is characterized by severe cardiomyopathy and mild myopathy appearing in the second or third decade, prominent arrhythmia with Wolf-Parkinson-White syndrome, and sometimes mental retardation. Patients reported as suffering from Antopol disease probably belong to this group. Dominant inheritance (autosomal or X linked) is likely in most families. The present report appears to be the first one to describe a rapidly fatal neonatal form of lysosomal glycogenosis without acid maltase deficiency. The mode of inheritance of this form is not known. Differential diagosis includes Pompe disease (similar histology) and cardiac phosphorylase b kinase deficiency (similar clinical course). The delineation of neonatal pseudo-Pompe disease makes enzymatic confirmation mandatory in each case suspected of Pompe disease.
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PMID:Nosology of lysosomal glycogen storage diseases without in vitro acid maltase deficiency. Delineation of a neonatal form. 938 33

Glycogen storage disease type II (GSD-II), also known as Pompe disease, is a rare autosomial recessive disease due to deficiency of lysosomal acid alpha-glucosidase (GAA). The infantile-onset form is the most severe, and most patients present with hypotonia and cardiomyopathy in early infancy. We report on a typical case of Pompe disease in a patient who died at 8 months of age due to aspiration pneumonia and hypertrophic cardiomyopathy. Genetic studies showed deficient GAA activity and mutation of the GAA gene with Gly615Arg (exon 13, G1845A). On autopsy, glycogen had markedly accumulated in the liver, myocardium and skeletal muscle. The neurons of the anterior horn of the spinal cord and medulla were also involved, but the cortex was spared. These neurological-histologic findings may explain the clinical features of poor motor function, decreased deep tendon reflexes and lack of mental retardation.
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PMID:Infantile-onset glycogen storage disease type II (Pompe disease): report of a case with genetic diagnosis and pathological findings. 1536 15

Danon disease, an X-linked cardioskeletal myopathy caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2), is clinically characterized by cardiomyopathy, myopathy, and variable mental retardation. The pathological hallmark of the disease is the absence of LAMP-2 immunohistochemical staining in muscle. The LAMP-2 gene mutations reported thus far are generally private mutations. We describe two cases of Danon disease with different clinical presentation, in whom we identified the same exon skipping mutation c.928G>A in the LAMP-2 gene. The first patient was affected by an early onset myopathy and hypertrophic cardiomyopathy (HCM) that partially improved with drug treatment. A first muscle biopsy at age 4 months showed markedly increased glycogen, and acid maltase deficiency was ruled out biochemically. A second muscle biopsy, performed at age 3(1/2) years, showed very mild abnormalities. The second child at age 15 years had mild, diffuse muscle weakness and wasting, moderate mental deficiency, and HCM. Two serial biopsies performed at age 8 and 15 years showed similar findings of multiple esterase-positive vacuoles in type I myofibers. In both patients the immunohistochemical study demonstrated the absence of LAMP-2 in skeletal muscle.
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PMID:Phenotypic heterogeneity in two unrelated Danon patients associated with the same LAMP-2 gene mutation. 1621 5

Hypertrophic cardiomyopathies have an estimated prevalence of 1/500. The analysis of the genes coding for the 10 most commonly involved sarcomeric proteins, fails to detect a mutation in about one third of cases. In some of these cases, cardiomyopathy can be attributed to a genetics storage disease with enlarged glycogen vacuolss (PRKAG2 deficiency, Danon disease, Pompe disease) and/or lysosomol vacuoles (Donon disease, Pompe disease, Fabry disease). These diseases all have in common a short PR interval. PRKAG2 deficiency is due to a dominant mutation of the gamma2 subunit of the cardiac AMP kinose. It leads to a storage cardiomyopathy which may be associated with sudden death in 10% of cases, due to ventricular arrhythmia or auriculoventricular blocks. Danon disease is an X-linked dominant inherited disease characterized by cardiomyopathy, squeletal myopathy and mental retardation. Cardiac transplantation is indicated in both affected men and women. In the infantile form of Pompe disease, enzyme replacement therapy with olglucosidase alpha shows efficacy on cardiac failure with a significant regression of ventricular hypertrophy on ECG, echocardiography and radiography
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PMID:[Inherited metabolic cardiomyopathies]. 1754 68

Lysosomal storage diseases (LSD) are inborn errors of metabolism secondary to lysosomal enzyme defects and are characterized by a progressive accumulation of nondigested macromolecules provoking cellular dysfunction and clinical manifestations. The diagnosis of these diseases can be confirmed easily in most cases by immuno-enzymatic techniques and molecular biology. Even though these enzymatic deficits result in an accumulation of pathological substrates, the underlying mechanisms responsible for the pathogenesis of the disease are not entirely known. Nevertheless, the distribution of the accumulated material determines the affected organs. More particularly in the central nervous system (CNS), neurons are often involved due to the accumulation of storage material and their incapacity of renewal. LSD can be responsible for mental retardation or for a neurodegenerative course in the central nervous system. The peripheral nervous system and the muscle can also be severely impaired. Hematopoietic stem cell transplantation was the first therapy, demonstrating efficacy especially on the neurological involvement of various LSD. Enzyme replacement therapy is now available for Gaucher disease, Fabry disease, mucopolysaccharidoses type I, type II, and type VI, and Pompe disease. Inhibition of the synthesis of the accumulated substrate by small molecules which also have the capacity to diffuse through the blood-brain barrier is another treatment option. New therapeutic strategies using the properties of molecular chaperones and of read-through molecules for nonsense mutations have been studied in vitro and hopefully will soon find clinical applications while intrathecal enzymes are currently studies in clinical trials for MPSII, MPS IIIA and MLD.
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PMID:Enzyme replacement therapy and substrate reduction therapy in lysosomal storage disorders with neurological expression. 2362 8


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