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)

The metabolism of ground substance in connective tissue of an 18-year-old boy with oculo-cerebro-renal syndrome was studied. He had characteristic clinical and laboratory findings described by Lowe et al. such as growth retardation, mental deficiency, glaucoma, cataracta, decreased muscle tone, metabolic acidosis, aminoaciduria and osteomalacia. The urinary excretion of acid glycosaminoglycans and of total hydroxyproline were 27 mg/day (as glucuronic acid) and 280 mg/day respectively on admission. Both values decreased to the upper limits of normal level transiently during treatment with alkali and vitamin D2. At that time, an improvement in bone abnormalities, a decrease of serum alkaline phosphatase, and an elevation of serum inorganic phosphate were observed. The therapy prevented him from progressive osteomalacia and cured him of it, but mucopolysacchariduria and hydroxyprolinuria did not disappear. Analytical electrophoresis on cellulose acetate sheets showed that urinary acid glycosaminoglycans were composed of undersulfated chondroitin 4-/6-sulfate and heparan sulfate with a ratio of 6:4, on admission. After oral administration of alkali, the excretion of heparan sulfate decreased and undersulfated chondroitin 4-/6-sulfate was determined as a main component of urinary acid glycosaminoglycans. The clinical and laboratory data in this case suggested that the increased excretion of acid glycosaminoglycans and total hydroxyproline was caused by abnormal metabolism in connective tissues, especially by the bone abnormalities, in this syndrome.
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PMID:Urinary excretion of acid glycosaminoglycans and hydroxyproline in a patient with oculo-cerebro-renal syndrome. 73 46

Clinical, light microscopical, ultrastructural, and biochemical studies were done on nerve and muscle biopsy specimens from five patients with the oculo-cerebral-renal syndrome of Lowe. Four patients were American Indians, a racial group in whom this disease has not previously been recognized. The hypotonia, areflexia, and diffuse atrophy of muscles are associated with slowed motor nerve conduction velocities, and the morphologic changes in sensory nerves are attributed to a "dying-back" phenomenon probably resulting from an unknown metabolic derangement.
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PMID:The oculo-cerebral-renal syndrome of Lowe. 112 72

The oculo-cerebral-renal syndrome of Lowe is an X-linked recessive disorder characterized by severe mental retardation, congenital cataracts, renal tubular dysfunction, growth retardation, hypotonia, glaucoma, and rickets. Recently, it has been found that serum concentrations of the muscle enzymes are elevated, providing evidence that there is primary muscle involvement in this disorder. The renal functional abnormalities that occur have also been further delineated. Renal tubular dysfunction presents within the first year of life, followed by a serum creatinine level that increases with age. Renal failure generally occurs in the fourth decade of life. We report two patients with Lowe's syndrome who presented with new onset of acute renal failure (ARF). Workup of their ARF established the diagnosis of acute tubular necrosis with evidence of rhabdomyolysis in one case. These patients were treated aggressively with dialysis and had subsequent recovery of renal function to their baseline state. We suggest that patients with Lowe's syndrome who present with an acute change in their renal function should be treated early with vigorous hydration therapy. If dialysis is indicated, it should be initiated. Furthermore, these patients should be promptly evaluated for evidence of rhabdomyolysis with alkalinization of the urine if possible.
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PMID:Acute tubular necrosis associated with Lowe's syndrome: possible role of rhabdomyolysis. 141 9

The Lowe oculocerebrorenal syndrome (OCRL; McKusick 309000) is an X-linked disorder characterized by congenital cataracts, muscular hypotonia, mental retardation, and Fanconi syndrome of the renal tubules. A pair of yeast artificial chromosomes (YACs) that span the Xq25-q26 translocation breakpoint in a female with OCRL were used as probes to screen cDNA libraries made from bovine lens and human kidney. The methods used to prepare the YACs as probes and to screen the libraries are presented in detail. Two different transcripts were found that map to the region around the Xq25-q26 breakpoint. These transcripts are now being studied to determine whether one or the other is a candidate gene for OCRL.
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PMID:Isolation of cDNA sequences around the chromosomal breakpoint in a female with Lowe syndrome by direct screening of cDNA libraries with yeast artificial chromosomes. 152 13

We describe three patients with Lowe (oculocerebrorenal) syndrome, emphasizing primarily the central nervous system and renal pathology. Using magnetic resonance imaging, we noted diffuse high T2 signals periventricularly, indicating significant white matter destruction, which may be responsible in part for the mental retardation, seizure disorder, hypotonia, and areflexia observed in the patients. In contrast to previously published reports, there was minimal renal tubular dysfunction; however, proteinuria was significantly increased in all patients. We believe that the observed proteinuria is primarily the result of glomerular pathology rather than renal tubular dysfunction and may represent a net loss of negative charges within the glomerular filter. This loss of charge may be linked to the increased excretion of glycosaminoglycans in the urine.
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PMID:Central nervous system and renal investigations in patients with Lowe syndrome. 157 8

Two brothers with the typical clinical features of oculocerebro-renal syndrome of Lowe exhibited delays in developmental milestones, muscular weakness and hypotonia, and high serum creatine kinase activity. The biopsied muscle revealed selective type 1 fiber atrophy and mild type 1 fiber predominance, similar to that observed in congenital fiber type disproportion myopathy. The abnormal fiber type distribution may be responsible for the common finding of muscle hypotonia in this syndrome.
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PMID:Congenital fiber type disproportion myopathy in Lowe syndrome. 260 2

Neurologic features of oculocerebrorenal (Lowe) syndrome include mental retardation, hypotonia, and areflexia. We performed a sural nerve biopsy, computerized tomography (CT) scan, and magnetic resonance imaging (MRI) scan on a 14-year-old boy with oculocerebrorenal syndrome with very mild renal disease. The nerve biopsy exhibited decreased number of myelinated fibers, normal myelination on remaining axons without redundant basal lamina, and no evidence of active degeneration or regeneration. MRI scan revealed diffuse and irregular foci of increased T2 signal with sparing of commissural fibers, pyramidal tracts, and cerebellar white matter. We conclude that both a peripheral axonopathy and a central demyelinating or gliotic process occurs in oculocerebrorenal syndrome in the absence of the severe renal disease that often complicates this disorder.
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PMID:MRI findings and peripheral neuropathy in Lowe's syndrome. 283 62

Lowe (oculocerebrorenal) syndrome (LS) is an X-linked disorder characterized by congenital cataracts, generalized hypotonia, mental retardation, and renal Fanconi syndrome. The basic defect remains unknown, but the possibility that fibroblasts express reduced sulfation of glycosaminoglycans has been studied in several laboratories. A mechanism involving overproduction of an enzyme (nucleotide pyrophosphatase) active against adenosine 3'-phosphate, 5'-phosphosulfate (PAPS) has been postulated. Decreased synthesis of normally sulfated glycosaminoglycans was also reported. We measured the synthesis of proteoglycans and glycosaminoglycans by incorporation of [3H]glucosamine and Na2(35)SO4 into cultured fibroblasts from four LS patients and related it directly to the synthesis in six normal fibroblast cultures. We found that the rate of synthesis varied greatly among the normal cultures (cv, 30%), but not significantly between LS and the normal. The LS fibroblasts' ability to sulfate glycosaminoglycans was assayed as the amount of 3H-glycosaminoglycan eluting at low ionic strength on anion exchange chromatography, the amount of non-sulfated disaccharide present in chondroitinase digests of labeled proteoglycans, and the ratio of 35S to 3H incorporation into proteoglycans. Each parameter suggested that the LS cells were synthesizing normally sulfated glycosaminoglycans (e.g. % delta Di-0S, 21 +/- 6 in normal; 27 +/- 6 in LS). The cells' ability to sulfate glycosaminoglycans was tested under conditions of markedly stimulated glycosaminoglycan synthesis, by treating the cultures with a beta-D-xyloside. LS and normal cells responded to the treatment by elevating the rate of synthesis of normally sulfated glycosaminoglycans (3.5-6-fold in normal, 3-7-fold in LS). Nucleotide pyrophosphatase activities were found to be elevated in each of our four LS cell strains as in the previous studies, excluding genetic heterogeneity as an explanation for our findings. We conclude that LS fibroblasts do not express defects in sulfation of glycosaminoglycans or in synthesis of proteoglycans.
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PMID:Proteoglycan synthesis in normal and Lowe syndrome fibroblasts. 357 Dec 27

The Oculo-cerebro-renal syndrome of Lowe is an X-linked recessive disorder characterised by mental and growth retardation, renal rickets with renal tubular acidosis, generalised aminoaciduria, hypotonia, cataracts, glaucoma and frontal bossing. Manifestations of this syndrome were seen in a girl with no family history of the disorder, but who was found to have a de novo balanced X/3 translocation, with a breakpoint at Xq25. She had also inherited a balanced 14/17 translocation from her father. It is postulated that the clinical picture may be the result of disruption of the X chromosome within the gene at the locus for Lowe syndrome, with non-random inactivation of the normal X, which may permit the expression of this X-linked recessive disorder in a girl.
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PMID:A balanced de novo X/autosome translocation in a girl with manifestations of Lowe syndrome. 395 80

The oculocerebrorenal (Lowe) syndrome is an X-linked recessive disorder characterized by congenital cataracts, hypotonia, developmental delay, poor growth and renal tubular dysfunction. Although the disorder has been mapped to chromosome Xq24-26, the underlying metabolic defect remains unknown. The renal component of the Lowe syndrome comprises tubular dysfunction, that is tubular proteinuria and generalized aminoaciduria progressing to the renal Fanconi syndrome, with later glomerular disease. Clinical problems typically include polyuria, acidosis, hypophosphatemia with rickets and eventually end stage renal disease. Hypercalciuria and its sequelae (nephrocalcinosis and nephrolithiasis) have not been described as cardinal features of the untreated disorder although they reportedly complicate vitamin D and calcium therapy of rickets. We discuss 5 boys with congenital cataracts, hypotonia, developmental delay, failure to thrive and the renal Fanconi syndrome who were diagnosed with the Lowe syndrome and in whom hypercalciuria was documented at diagnosis. We conclude that hypercalciuria and its sequelae may occur commonly in patients with the Lowe syndrome as a component of tubular dysfunction or a complication of therapy.
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PMID:Hypercalciuria and nephrocalcinosis in the oculocerebrorenal syndrome. 786 19


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