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)

Lecithin-cholesterol acyltransferase is responsible for the formation of most cholesteryl esters in plasma. Absence of this enzyme can result in a rare syndrome that includes diffuse corneal opacities, normocytic normochromic anemia, proteinuria, renal failure, and premature arteriosclerosis. The deficiency can be inherited in an autosomal recessive manner, or it can be acquired through liver disease. Diagnosis requires a high index of suspicion and documentation of impairment of enzyme mass or activity (or both). This article includes a case report of the first United States citizen known to have lecithin-cholesterol acyltransferase deficiency. The authors review the literature related to this disease.
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PMID:Lecithin-cholesterol acyltransferase deficiency: first report of case in a United States citizen. 802 2

The molecular defects in the lecithin:cholesterol acyltransferase (LCAT) gene have been identified in a 52-year-old patient with classic LCAT deficiency, presenting with corneal clouding and proteinuria. Plasma total cholesterol was normal, triglycerides were elevated, whereas high density lipoprotein (HDL) cholesterol (8 mg/dl) and plasma cholesteryl esters (6% of total cholesterol) were markedly reduced. Plasma cholesterol esterification rate (pCER) was zero, alpha-LCAT activity, assayed using an HDL-like proteoliposome substrate was reduced to 1.6% of control, and LCAT mass was 3.7% of normal plasma levels. DNA sequence analysis of the proband's LCAT gene identified a C to A substitution, converting tyr83 to a stop codon, and a T to A transition, replacing tyr156 by asn. Restriction analysis of PCR-amplified DNA from the proband, a control and his four children using the enzymes Acc I and Rsa I established that the patient is a compound heterozygote for both mutations. The two children, heterozygous for the stop codon defect, were phenotypically indistinguishable from the two with the tyr156 defect. In vitro expression of LCAT (tyr156-->asn) in human embryonic kidney-293 cells established the functional significance of this mutation. The secreted translation product had only 6% of control mass and no detectable CER; however, the residual LCAT mass of the in vitro expressed LCAT (tyr156-->asn) demonstrated a specific alpha-LCAT activity of 30% of control, suggesting that this amino acid substitution results in a mutant enzyme that retains some enzymic activity, but may be rapidly catabolized. In summary, we have identified two unique defects in the LCAT gene that lead to the expression of classic LCAT deficiency in this kindred.
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PMID:Two different allelic mutations in the lecithin:cholesterol acyltransferase (LCAT) gene resulting in classic LCAT deficiency: LCAT (tyr83-->stop) and LCAT (tyr156-->asn). 844 42

We investigated the genetic defects in two patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. Their clinical manifestations including corneal opacities, anemia, proteinuria, and hypoalphalipoproteinemia were identical for familial LCAT deficiency. Their LCAT activities and the cholesterol esterification rate (CER) were nearly zero, and their LCAT masses were below 10% of normal control values. Sequence analysis of the amplified DNA of case 1 revealed one base deletion of G at base 873 (first position of Val264) in exon 6, leading to a premature termination by frameshift. Sequence analysis of amplified DNA of case 2 revealed a single G to A converting Gly (GGT) to Ser (AGT) substitution at residue 344. When COS-1 cells were transfected with these mutants, LCAT activity in the medium was nearly zero, and the LCAT mass was undetectable (< 0.01 microgram/ml). In contrast, LCAT activity in the medium of COS-1 cells, transfected with wild-type LCAT, was 1.7 nmol/h per ml and the LCAT mass was 0.09 micrograms/ml. The LCAT mass in the cell lysates of the mutants was less than 12% of control for case 1 and 18% of control for case 2. Northern blot analysis of the mRNA of COS-1 cells transfected with the mutants showed the same amounts of LCAT mRNA as compared with wild-type LCAT. Biosynthesis of mutant LCATs was analyzed by pulse-chase and immunocytochemistry in transfected baby hamster kidney cells. SDS-PAGE/fluorography demonstrated that wild-type LCAT was synthesized as a high-mannose type of 56 kDa, which was very slowly converted to a mature form of 67 kDa and was secreted into the media. In contrast to the wild-type LCAT, the mutant precursors were not processed into the mature form but slowly degraded along with chase times. On steady and continuous labeling in the case of wild-type LCAT, the mature 67 kDa form was observed in both the cell lysate and media, whereas no mature form was detected in the cell lysates and media which were transfected mutant LCATs. These data suggest that the mutant LCATs are actually synthesized in an amount comparable to that of wild-type, but they are slowly degraded without being processed into the mature form. The immunocytochemistry revealed that mutant LCATs were mainly retained in the endoplasmic reticulum. These data suggest that these two mutations may disrupt the mutant LCATs' transport from the endoplasmic reticulum into Golgi apparatus, resulting in LCAT deficiency.
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PMID:Two novel point mutations in the lecithin:cholesterol acyltransferase (LCAT) gene resulting in LCAT deficiency: LCAT (G873 deletion) and LCAT (Gly344-->Ser). 865 71

We identified a novel missense mutation in the lecithin:cholesterol acyltransferase gene in a new case of lecithin:cholesterol acyltransferase (LCAT) deficiency. The patient was a 64-year-old diabetic Japanese male who showed an extremely low level of serum high-density lipoprotein-cholesterol, corneal opacities, anemia, and proteinuria. Both the patient's LCAT activity and mass were markedly low. DNA sequence analysis of the LCAT gene showed an A-to-T transition at base 97 in exon 1, and predicted a change in asparagine to isoleucine at the 5th amino acid of the protein. Restriction analysis of polymerase chain reaction-amplified DNA using Ase I showed that the patient was homozygous for this mutation. Our results suggested that asparagine 5 was an important amino acid and substitution with isoleucine caused marked reduction of LCAT activity and mass, resulting in LCAT deficiency.
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PMID:A novel missense mutation (Asn5-->Ile) in lecithin: cholesterol acyltransferase (LCAT) gene in a Japanese patient with LCAT deficiency. 900 16

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

The esterification of free cholesterol (FC) in plasma, catalyzed by the enzyme lecithin:cholesterol acyltransferase (LCAT; EC 2.3.1.43), is a key process in lipoprotein metabolism. The resulting cholesteryl esters (CE) represent the main core lipids of low (LDL) and high density lipoproteins (HDL). Primary (familial) LCAT-deficiency (FLD) is a rare autosomal recessive genetic disease caused by the complete or near absence of LCAT activity. In fish-eye disease (FED), residual LCAT activity is still detectable. Here, we describe a 32-year-old patient with corneal opacity, very low LCAT activity, reduced amounts of CE (low HDL-cholesterol level), and elevated triglyceride (TG) values. The lipoprotein pattern was abnormal with regard to lipoprotein composition and concentration, but distinct lipoprotein classes were still present. Despite of typical features of glomerular proteinuria, creatinine clearance was normal. DNA sequencing and restiction fragment analyses revealed two separate mutations in the patient's LCAT gene: a previously described G to A transition in exon 4 converting Arg140 to His, inherited from his mother, and a novel G to C transversion in exon 2 converting Gly71 to Arg, inherited from his father, indicating that M.P. was a compound heterozygote. Determination of enzyme activities of recombinant LCAT proteins obtained upon transfection of COS-7 cells with plasmids containing G71R-LCAT or wild-type LCAT cDNA revealed very low alpha- and absence of beta-LCAT activity for the G71R mutant. The identification of the novel G71R LCAT mutation supports the proposed molecular model for the enzyme implying that the "lid" domain at residues 50-74 is involved in enzyme:substrate interaction. Our data are in line with the hypothesis that a key event in the etiology of FLD is the loss of distinct lipoprotein fractions.
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PMID:Compound heterozygosity (G71R/R140H) in the lecithin:cholesterol acyltransferase (LCAT) gene results in an intermediate phenotype between LCAT-deficiency and fish-eye disease. 1621 49

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 a rare metabolic disease with lipid deposition in several organs. The authors report a man with hypertension and proteinuria. Renal biopsy revealed glomerular changes, including peculiar thrombus-like deposits, consistent with LCAT deficiency. He was found to be compound heterozygous for two mutations of the LCAT gene. He received a kidney graft from his father. The authors also describe LCAT deficiency-related lesions in the explanted native kidneys and in biopsies at 2 days, 6 weeks, and 1 year after transplantation. The morphology of this disease is characteristic, and the diagnosis should be suspected from the ultrastructural findings.
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PMID:Lecithin: Cholesterol Acyltransferase (LCAT) Deficiency: renal lesions with early graft recurrence. 2132 22


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