Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome-deficient disorders including Zellweger syndrome, neonatal adrenoleukodystrophy and infantile Refsum disease are characterized by hypotonia, psychomotor delay, hepatomegaly and dysmorphism. Multiple peroxisomal enzymes are deficient in these disorders probably due to the defect of transport machinery of enzymes. Defects of beta-oxidation enzymes causes an accumulation of very-long-chain fatty acids, which is closely related to the pathogenesis. Catalase, a marker enzyme of peroxisome, is distributed in the cytosol. Immunocytochemical staining of peroxisomes using anti-catalase is a useful tool for prenatal and postnatal diagnosis. Although the primary etiology of peroxisomal deficiency has not been determined, genetic heterogeneity was clarified by complementation studies. At least 8 genes are involved in the formation of functional peroxisomes.
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PMID:[Clinical biochemical and genetic aspects of peroxisome-deficient disorders]. 137 33

Several childhood multisystem disorders with prominent ophthalmological manifestations have been ascribed to the malfunction of the peroxisome, a subcellular organelle. The peroxisomal disorders have been divided into three groups: 1) those that result from defective biogenesis of the peroxisome (Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum's disease); 2) those that result from multiple enzyme deficiencies (rhizomelic chondrodysplasia punctata); and 3) those that result from a single enzyme deficiency (X-linked adrenoleukodystrophy, primary hyperoxaluria type 1). Zellweger syndrome, the most lethal of the three peroxisomal biogenesis disorders, causes infantile hypotonia, seizures, and death within the first year. Ophthalmic manifestations include corneal opacification, cataract, glaucoma, pigmentary retinopathy and optic atrophy. Neonatal adrenoleukodystrophy and infantile Refsum's disease appear to be genetically distinct, but clinically, biochemically, and pathologically similar to Zellweger syndrome, although milder. Rhizomelic chondrodysplasia punctata, a peroxisomal disorder which results from at least two peroxisomal enzyme deficiencies, presents at birth with skeletal abnormalities and patients rarely survive past one year of age. The most prominent ocular manifestation consists of bilateral cataracts. X-linked (childhood) adrenoleukodystrophy, results from a deficiency of a single peroxisomal enzyme, presents in the latter part of the first decade with behavioral, cognitive and visual deterioration. The vision loss results from demyelination of the entire visual pathway, but the outer retina is spared. Primary hyperoxaluria type 1 manifests parafoveal subretinal pigment proliferation. Classical Refsum's disease may also be a peroxisomal disorder, but definitive evidence is lacking. Early identification of these disorders, which may depend on recognizing the ophthalmological findings, is critical for prenatal diagnosis, treatment, and genetic counselling.
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PMID:The peroxisome and the eye. 171 72

We describe a relatively new syndrome in four children with characteristic facial dysmorphism, sensorineural hearing loss, severe visual impairment with retinitis pigmentosa, hypotonia, hepatomegaly, and severe developmental delay. Two patients had intracranial hemorrhage secondary to a vitamin K-responsive clotting defect; both had steatorrhea. Liver biopsy specimens in two children showed an accentuated lobular architecture with prominent fibrous bands in the portal area. In one, the ultrastructure showed accumulation of abnormal substances and occasional trilaminar structures in hepatocytes and other cells. All four patients had elevated serum phytanic acid concentrations (0.3 to 2.7 mg/dl, normal less than 0.2 mg/dl) and deficient fibroblast phytanic acid oxidase activity (0.1 to 6.7 pmol/mg protein/hr, normal 23 to 87 pmol/mg protein/hr). Serum pipecolic acid was 7 to 55 times normal, and the ratio of C26/C22 very long chain fatty acids was increased (0.10 to 0.22; normal less than 0.03). This characteristic syndrome has been described in several children and called infantile Refsum disease or phytanic acid storage disease. Its relationship to neonatal adrenoleukodystrophy, hyperpipecolic acidemia, and Zellweger syndrome is discussed.
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PMID:Dysmorphic syndrome with phytanic acid oxidase deficiency, abnormal very long chain fatty acids, and pipecolic acidemia: studies in four children. 241 87

Nine cases of neonatal adrenoleukodystrophy are described. All patients had abnormal facial features, moderate to severe hypotonia, hepatomegaly, and retinitis pigmentosa. The clinical course was rapidly progressive in six cases and more protracted in three others. Biological signs of adrenal insufficiency were present in five cases. CT scan showed a demyelinating process in four patients. Trilamellar inclusions were found in the liver of four cases and dark and complex lipidic inclusions in three other cases. In the three necropsied patients there was severe alteration of the white matter involving particularly the cerebellum in two cases. Gyral and cytoarchitectonic disturbances were absent in all three cases. Increased plasma levels of very long chain fatty acids (8/8), phytanic acid (7/8) and bile fluid trihydroxycoprostanic acid (2/4) confirmed the deficiency of multiple peroxisomal enzymes. Clinical, histopathological and biochemical findings of these nine cases are compared to those reported in other neonatal adrenoleukodystrophy cases and to those of other neonatal peroxisomal disorders, that is cerebro-hepato-renal syndrome of Zellweger and infantile Refsum's disease.
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PMID:Neonatal adrenoleukodystrophy. 242 Sep 40

We reported two siblings of Leber's congenital amaurosis associated with increased level of very long chain fatty acid (VLCFA) in blood. Case 1, a 3 1/2-year-old boy had congenital blindness, severe psychomotor retardation, hepatomegaly, profound hypotonia, loss of deep tendon reflexes, muscular atrophy and weakness, and non-convulsive status epilepticus characterized by a sudden respiratory failure, and also showed a flat electroretinogram, non-pigmentary retinal degeneration, severe atrophy of the brain stem and cerebellum, hepatic fibrosis, decreased motor and sensory conduction velocities and atlanto-axial instability. Sural nerve biopsy revealed severely decreased number of total myelinated fibers without remarkable demyelination or remyelination. Case 2, an elder sister of case 1, with pigmentary retinal degeneration, hepatomegaly and pericarditis had died at 3 months. Autopsy revealed hypomyelination and heterotopy of the cerebral white matter, hepatic fibrosis, renal microcysts and normal adrenal cytoarchitecture. In case 1, the level of VLCFA was increased twofold and sevenfold of controls in serum and in red cell membrane, respectively. Phytanic or trihydroxycholestanoic acid was not detected in the serum and bile. Normal shaped peroxisomes were definitely recognized in biopsied liver by means of electronmicroscopic histochemistry. From the above findings, these patients was thought to be a new variant of peroxisomal disorders relating to degradation of VLCFA, other than Zellweger syndrome, infantile Refsum disease and infantile adrenoleukodystrophy. It was concluded that peroxisomal functions should be studied in cases of Leber's congenital amaurosis.
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PMID:[Two siblings of Leber's congenital amaurosis with an increase in very long chain fatty acid in blood: relationship between peroxisomal disorders and Leber's congenital amaurosis]. 278 58

This report describes a patient with high serum phytanic acid concentration due to phytanic acid alpha-oxidase deficiency (classical Refsum disease). He presented unusually early, hypotonia and developmental delay being apparent by 7 months. A generalized peroxisomal disorder (so-called 'infantile Refsum disease') was excluded by analyses of pristanic acid, very long-chain fatty acids, bile acids and plasmalogen synthesis. The early presentation raises the possibility of in utero exposure to phytanate.
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PMID:Phytanic acid alpha-oxidase deficiency (Refsum disease) presenting in infancy. 752 31

Peroxisomes or microbodies are peculiar subcellular organelles with an important role in the metabolism of a variety of different organic compounds. Particularly they are an important site of bile acids synthesis. Some hepatic diseases, mainly cholestatic, can to be reconnected at disorders of bile acids synthesis by these organelles. From the biochemical point some diseases present alterations of the cholesterol side chain (Zellweger syndrome, pseudo-Zellweger syndrome, infantile Refsum's disease, neonatal adrenoleukodystrophy), other diseases present errors involving the steroid nucleus (familial giant cell hepatitis). Zellweger disease or cerebro-hepato-renal syndrome is characterized clinically by skeletal changes, muscle hypotonia, renal cysts, psychosomatic retardation and persistent cholestasis and from the ultrastructural standpoint by the virtual absence of liver cell peroxisomes. Pseudo-Zellweger disease shows many of the clinical features of Zellweger disease but differs from this condition on account of the presence of abundant peroxisomes in the liver cells. Infantile Refsum's disease and neonatal adrenoleukodystrophy show typical clinical disorders and liver damage leading to cirrhosis. "Familial giant cell hepatitis" is characterized by jaundice from the first days of life, hepatosplenomegaly, cholestasis, lack of physical malformations. The disorder is due to defective biosynthesis of the bile acids with formation of allo-bile acids.
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PMID:[Liver pathologies due to peroxisome disorders]. 818 91

Peroxisome biogenesis disorders (PBDs) are severe autosomal recessive neurological diseases caused by a defect of peroxisomal assembly factors. Zellweger syndrome, the most severe phenotype, is characterized by hypotonia, psychomotor retardation and neuronal migration disorder. Neonatal adrenoleukodystrophy and infantile Refsum disease are milder phenotypes of this disease. Thirteen complementation groups have been established since the genetic heterogeneity of PBDs was elucidated in 1988. Eleven genes for PBDs have been identified either by a functional complementation cloning or by EST homology searches. In 1992, the first gene for PBDs, PEX2, was identified. It encodes peroxisomal integral membrane protein with a RING finger domain. PEX5 and PEX7 are the genes for peroxisomal targeting signal (PTS)-1 and -2 receptors, respectively. PEX3, PEX16 and PEX19 are considered to be required for the early stage of peroxisome biogenesis. PEX13 protein has an SH3 docking site that binds to the PTS-1 receptor. PEX1 and PEX6 encode ABC protein, and PEX10 and PEX12 also encode integral membrane protein, with RING finger. Temperature-sensitivity, whereby peroxisomal biogenesis and metabolic dysfunctions are restored at 30 degrees C in cells from mild phenotypes, is a useful event for predicting the clinical severity and for elucidation of peroxisome biogenesis. Investigations using knockout mice are expected to facilitate understanding of migration disorders.
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PMID:Clinical, biochemical and genetic aspects and neuronal migration in peroxisome biogenesis disorders. 1140 37

Mutations in 12 different PEX genes can cause a generalized peroxisomal biogenesis disorder with clinical phenotypes ranging from Zellweger syndrome to infantile Refsum disease. To identify the specific PEX gene to be sequenced, complementation analysis is first performed in fibroblasts using catalase immunofluorescence. A patient with a relatively mild phenotype of infantile cholestasis, hypotonia and motor delay had elevated plasma very long-chain fatty acids and bile acid precursors, but fibroblast studies revealed normal or only mildly abnormal peroxisomal parameters and mosaic catalase immunofluorescence. This mosaicism persisted even when the incubation temperature was increased from 37 degrees C to 40 degrees C, a maneuver previously shown to abolish mosaicism by exacerbating peroxisomal dysfunction. As mosaicism precludes complementation analysis, a candidate gene approach was employed. After PEX1 sequencing was unrewarding, PEX12 sequencing revealed homozygosity for a novel c.102A>T (p.R34S) missense mutation affecting a partially conserved residue in the N-terminal region important for localization to peroxisomes. Transfection of patient fibroblasts with wild-type PEX12 cDNA confirmed that a PEX12 defect was the basis for the PBD. Homozygosity for c.102A>T was identified in a second patient of similar ethnic origin also presenting with a mild phenotype. PEX12 is a highly probable candidate gene for direct sequencing in the context of a mild clinical phenotype with mosaicism and minimally abnormal peroxisomal parameters in fibroblasts.
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PMID:A novel PEX12 mutation identified as the cause of a peroxisomal biogenesis disorder with mild clinical phenotype, mild biochemical abnormalities in fibroblasts and a mosaic catalase immunofluorescence pattern, even at 40 degrees C. 1753 73

Zellweger syndrome (ZS) is a severe manifestation of disease within the spectrum of peroxisome biogenesis disorders that includes neonatal adrenoleukodystrophy, infantile Refsum disease, and rhizomelic chondroplasia punctata. Patients with ZS present in the neonatal period with a characteristic phenotype of distinctive facial stigmata, pronounced hypotonia, poor feeding, hepatic dysfunction, and often seizures and boney abnormalities. In patients with ZS, a mutation in one of the PEX genes coding for a peroxin (a peroxisome assembly protein) creates functionally incompetent organelles causing an accumulation of very long chain fatty acids (VLCFA), among other complications. Despite an absence of treatment options, prompt diagnosis of ZS is important for providing appropriate symptomatic care, definitive genetic testing, and counseling regarding family planning.
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PMID:Child neurology: Zellweger syndrome. 2367 47


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