Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To evaluate the biochemical and molecular mechanisms leading to glomerulosclerosis and the variable development of atherosclerosis in patients with familial lecithin cholesterol acyl transferase (LCAT) deficiency, we generated LCAT knockout (KO) mice and cross-bred them with apolipoprotein (apo) E KO, low density lipoprotein receptor (LDLr) KO, and cholesteryl ester transfer protein transgenic mice. LCAT-KO mice had normochromic normocytic anemia with increased reticulocyte and target cell counts as well as decreased red blood cell osmotic fragility. A subset of LCAT-KO mice accumulated lipoprotein X and developed proteinuria and glomerulosclerosis characterized by mesangial cell proliferation, sclerosis, lipid accumulation, and deposition of electron dense material throughout the glomeruli. LCAT deficiency reduced the plasma high density lipoprotein (HDL) cholesterol (-70 to -94%) and non-HDL cholesterol (-48 to -85%) levels in control, apoE-KO, LDLr-KO, and cholesteryl ester transfer protein-Tg mice. Transcriptome and Western blot analysis demonstrated up-regulation of hepatic LDLr and apoE expression in LCAT-KO mice. Despite decreased HDL, aortic atherosclerosis was significantly reduced (-35% to -99%) in all mouse models with LCAT deficiency. Our studies indicate (i) that the plasma levels of apoB containing lipoproteins rather than HDL may determine the atherogenic risk of patients with hypoalphalipoproteinemia due to LCAT deficiency and (ii) a potential etiological role for lipoproteins X in the development of glomerulosclerosis in LCAT deficiency. The availability of LCAT-KO mice characterized by lipid, hematologic, and renal abnormalities similar to familial LCAT deficiency patients will permit future evaluation of LCAT gene transfer as a possible treatment for glomerulosclerosis in LCAT-deficient states.
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PMID:Analysis of glomerulosclerosis and atherosclerosis in lecithin cholesterol acyltransferase-deficient mice. 1127 14

Lecithin-cholesterol acetyltransferase (LCAT) is involved in the synthesis of plasma cholesteryl esters and is pivotal in the maturation of plasma high-density lipoprotein (HDL) and conversion of HDL3 to HDL2. In nephrotic syndrome (NS), the ratio of HDL2 to HDL3 is low even though the total concentration of HDL is generally normal. We hypothesize that the reduced HDL2/HDL3 ratio in NS is due to urinary losses of LCAT, leading to plasma LCAT deficiency. To test this hypothesis, Sprague-Dawley rats were randomized to NS (given 130 mg puromycin aminonucleoside on day 1 and 60 mg ip on day 14) or control groups and were studied on day 30. To dissect the effect of proteinuria from hypoalbuminemia, a group of Nagase rats with inherited hypoalbuminemia was included. Hepatic LCAT and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA abundance and plasma and urine LCAT activity were measured. The NS group showed a fourfold rise in serum cholesterol and triglycerides, a fivefold rise in free cholesterol, and a fourfold fall in the HDL-to-total cholesterol ratio. Despite severe hypoalbuminemia, the Nagase rats showed only a mild elevation of serum cholesterol and triglycerides with a normal serum free cholesterol and HDL-to-total cholesterol ratio. The NS group exhibited a normal hepatic LCAT-to-GAPDH mRNA ratio, a marked reduction in plasma LCAT activity, and a significant increase in urinary LCAT excretion. LCAT/GAPDH mRNA and plasma and urine LCAT were normal in Nagase rats. Thus NS led to heavy urinary losses and reduced plasma concentration of LCAT, despite normal hepatic LCAT mRNA abundance. However, hypoalbuminemia, per se, without proteinuria as seen in the Nagase rats had no effect on plasma LCAT or the HDL-to-total cholesterol ratio. Therefore, proteinuria, not hypoalbuminemia, causes LCAT deficiency and a depressed HDL-to-total cholesterol ratio in NS.
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PMID:Acquired lecithin-cholesterol acyltransferase deficiency in nephrotic syndrome. 1129 24

We report a case of familial LCAT deficiency, diagnosed in a 35 year old women. The disease manifested itself by a presence of proteinuria, corneal opacities and haemolytic anaemia with target cells. Suspecion of familial LCAT deficiency was based on renal biopsy, which revealed characteristic serpiginous fibrillar deposits in electron microscopy. The diagnosis was confirmed by a marked decrease of estrified cholesterol, low HDL-cholesterol concentration, decrease of LCAT activity in serum, typical "stacked coins" picture of HDL lipoproteins in electron microscopy examination and positive familial history--diagnosis of LCAT deficiency in dialysed brother of patient.
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PMID:[Familial LCAT deficiency--clinical picture. Case report]. 1139 66

Familial deficiency of lecithin-cholesterol acyltransferase (LCAT) was described by Norum and Gjone in 1967. LCAT (EC 2.3.1.43) is a serum enzyme involved in reverse cholesterol transport. LCAT deficiency is associated with percentage increase of free cholesterol and decrease of esterified cholesterol, and disturbances in lipoprotein particles structure, because cholesterol esters form the lipoprotein core. Lipid disorders involve also other organs, such as kidneys, cornea and erythrocytes; with clinical manifestations of proteinuria, usually associated with renal insufficiency, corneal opacities and haemolytic anemia. Gene encoding LCAT is localized in region q 21-22 on chromosome 16. It consists of 6 exons, divided by 5 introns and spans 4.2 bp. Familial LCAT deficiency is an autosomal recessive disorder. In LCAT deficient patients several mutations in all 6 exons have been described. Clinical manifestations of familial LCAT deficiency are highly variable, although no or only low LCAT activity is present and this may suggests that expression of the disease is modulated by additional environmental factors and genes of minor importance.
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PMID:[Familial LCAT deficiency]. 1195 19

Lecithin:cholesterol acyltransferase (LCAT) is a key enzyme for the transfer of mammalian cholesterol from peripheral tissues to the liver. In patients deficient in LCAT, serum cholesterol levels rise and can lead to corneal opacity, proteinuria, anemia, and kidney failure. As early as 1968, relatively low volume transfusion of normal plasma was shown to temporarily correct the abnormal lipoprotein profiles in LCAT-deficient patients. However, despite the cloning, study, and extensive expression of LCAT in mammalian cell lines, there is still no viable, clinical therapy for LCAT deficiency. The current study was initiated to provide a source of recombinant human LCAT for enzyme replacement therapy. Accordingly, human LCAT has been cloned and expressed for the first time in a human cell line. The recombinant LCAT secreted by these cells was purified by phenyl-Sepharose chromatography, analyzed to determine the nature of its glycosylation, and tested for its enzymatic properties. The activity and basic kinetic parameters for the enzyme were determined using both a fluorescent water-soluble substrate and a macromolecular (proteoliposome) substrate. The enzymatic properties and the carbohydrate components of the recombinant LCAT were all sufficiently similar to those of the circulating human plasma enzyme, suggesting that this source of LCAT may be appropriate for use in some form of enzyme replacement therapy.
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PMID:Characterization of lecithin:cholesterol acyltransferase expressed in a human lung cell line. 1524 36

Familial LCAT deficiency (FLD) is a rare genetic disorder associated with corneal opacities, anaemia and proteinuria with renal failure. Here we report detailed analyses on plasma lipids, lipoproteins, and the molecular defect in two siblings from a Polish family presenting classical symptoms of FLD and their family members with newly discovered Val309Met mutation in exon 6 of LCAT gene. Both patients displayed low total (2.19 and 2.94 mmol/l) and HDL-cholesterol concentrations (0.52 and 0.48 mmol/l), low percentage of cholesteryl esters (CE) (11.1 and 12%), and decreased apo AI and apo AII serum levels. Low LDL-cholesterol, apo B and Lp(a) levels, and increased oleate/linoleate ratios in CE could be of importance in the development of atherosclerosis in these patients with low HDL-cholesterol. LCAT activity was 10% of normal, alpha-LCAT activity was 0, and LCAT concentration was undetectable by immunoassay. Plasma CETP activity was at lower limits of normal. PCR and sequence analysis of DNA from the proband and affected brother revealed a novel G-->A mutation in exon 6 of LCAT gene, which resulted in an amino acid substitution of valine for methionine (Val309Met). The proband and affected brother were both homozygous carriers, while the mother, siblings and children of patients were heterozygous carriers of a newly discovered mutation. This is the first LCAT mutation described in the Slavic population.
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PMID:Familial lecithin-cholesterol acyltransferase deficiency: biochemical characteristics and molecular analysis of a new LCAT mutation in a Polish family. 1605 Dec 54

Familial lecithin-cholesterol acyltransferase deficiency is an uncommon autosomal recessive disorder from a heritable defect in esterification of plasma cholesterol. In 1968, the disease was described by Gjone and Norum in Norway. Our case was a 38-year-old woman. Her disease was manifested by presence of lower extremities edema, proteinuria, corneal opacities, increased plasma cholesterol, and hemolytic anemia. Suspicion of the disease was based on renal biopsy, which revealed mesangial expansion and capillary wall widening with clusters of foamy cells in the mesangium. Immunofluorescence study was nonspecific, but specific findings of electron microscopy showed deposition of lipid in the glomerular basement membrane and mesangium. This is the first report of lecithin-cholesterol acyltransferase deficiency in Iran.The diagnosis was confirmed by a low high-density lipoprotein cholesterol concentration, decreased activity of lecithin-cholesterol acyltransferase in plasma, and positive familial history of the disease.
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PMID:Familial lecithin-cholesterol acyltransferase deficiency. 1924 91

Familial LCAT deficiency (FLD) is a disease characterized by a defect in the enzyme lecithin:cholesterol acyltransferase (LCAT) resulting in low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers, presenting classical signs of FLD, were shown to be homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 and causes a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differs markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE epsilon2 allele could be a novel mechanism leading to dysbetalipoproteinemia.
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PMID:Characterization of a new LCAT mutation causing familial LCAT deficiency (FLD) and the role of APOE as a modifier gene of the FLD phenotype. 1951 69

A 31-year-old man with no significant medical history presented with a 5-day history of progressive left upper quadrant abdominal pain. Physical examination revealed a tender guarded abdomen, no icterus, and bilateral corneal "arcus senilis"-like changes. Laboratory workup showed a mild normocytic, normochromic anemia; and target cells were seen in the peripheral blood smear. Serum was turbid; and the lipid profile showed elevated total cholesterol, low high-density lipoprotein cholesterol, and elevated triglycerides. Urinalysis revealed nephrotic range proteinuria with microhematuria. An abdominal computed tomographic scan demonstrated a homogeneously enlarged spleen. The patient was discharged after symptomatic treatment to be followed as an ambulatory patient. Several days later, he returned with severe left upper quadrant pain and was admitted to the surgical service for further evaluation. A splenectomy was performed for a suspected splenic lymphoma. Upon gross examination, spleen was moderately enlarged, weighing 780 g. Sectioning revealed a beefy red cut surface without gross lesions. Wright-Giemsa-stained touch imprints showed many sea-blue histiocytes. A renal biopsy was also performed, demonstrating focal segmental glomerular sclerosis and mesangial expansion with extramembranous and intramembranous deposition of lipids. In the absence of hematologic malignancy and in light of the abnormal lipid profile, a disorder of lipid metabolism was suspected. Histologic and ultrastructural findings in the kidney and spleen raised the likelihood of lecithin-cholesterol acyltransferase (LCAT) deficiency, which was confirmed by the markedly decreased serum LCAT activity and serum LCAT mass. We describe a case with the triad of splenomegaly with sea-blue histiocytes, nephropathy, and dyslipidemia in a patient with LCAT deficiency.
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PMID:Splenomegaly with sea-blue histiocytosis, dyslipidemia, and nephropathy in a patient with lecithin-cholesterol acyltransferase deficiency: a clinicopathologic correlation. 1959 52

Familial lecithin: cholesterol acyltransferase (LCAT) deficiency is an autosomal recessive disorder characterized by corneal opacity, hemolytic anemia, proteinuria, and a low serum level of high-density lipoprotein cholesterol (HDL-C). Also, LCAT activity is remarkably decreased or absent. A 57-year-old Japanese man presented with corneal opacity, proteinuria, and a very low serum level of HDL-C. His LCAT activity was too low to measure. From clinical observations and results of examinations, we suspected LCAT deficiency. We performed a kidney biopsy and gene analysis. Light microscopy revealed the vacuolation of glomerular capillary tufts. Electron microscopy revealed small deposits in the glomerular basement membrane (GBM), extracellular matrix, and vascular endothelial cells. We identified a homozygous C to T point mutation at nucleotide 501 (g.501 C>T) of exon 4 at codon 140, resulting in an arginine (Arg) to cysteine (Cys) amino acid substitution (A140C) in the patient. These findings were characteristic of LCAT deficiency, which was confirmed to be due to a mutation that has only been reported in Japan.
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PMID:Point mutation (C to T) of the LCAT gene resulting in A140C substitution. 2093 2


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