Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020473 (hyperlipidemia)
 15,891 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphism at the apolipoprotein E (ApoE) locus is an important factor in the development of remnant (Type III) hyperlipidemia and also influences the distribution of cholesterol concentrations in the population. The new method for ApoE phenotyping described here gives good results with simple apparatus. Serum (10 microL) is digested with sialidase (EC 3.2.1.18), delipidated, and redissolved in 6 mol/L urea. Electrofocusing is carried out in agarose, followed by immunoblotting with a monoclonal antibody to ApoE and an anti-immunoglobulin-peroxidase conjugate. Sialidase-catalyzed digestion effectively removes sialated forms of ApoE, which eases interpretation. This method can be used in nonspecialist laboratories and is particularly suited for assay of large numbers of samples.
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PMID:Apolipoprotein E phenotype determined by agarose gel electrofocusing and immunoblotting. 279 Dec 74

Two patients with marked elevation of plasma and very low density lipoprotein (VLDL) lipids were investigated to establish the molecular basis of their hyperlipidaemia. In one the demonstration of the apolipoprotein E 2/2 phenotype substantiated the diagnosis of type III hyperlipidaemia. In the other the E4/3 phenotype excluded this diagnosis. In both cases oligonucleotide probing of amplified DNA and isoelectric focusing (IEF) of apo VLDL identified the correct apolipoprotein E phenotype as defined by peptide mapping and IEF of purified apolipoprotein E after modification with iodoacetic acid. Probing of amplified DNA clearly distinguishes the three common variants of apolipoprotein E (E2, E3, E4) and facilitates the diagnosis of type III hyperlipidaemia.
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PMID:Apolipoprotein E variation in patients with hyperlipidaemia: DNA and protein phenotyping. 234 20

We report a common DNA polymorphism of the apolipoprotein E (apoE) gene detected with the enzyme HpaI. In an individual who is heterozygous for the polymorphism, two hybridising fragments of DNA, one of 50 kb (the H1 allele) and one of 20 kb (the H2 allele) are detected. In 54 controls the frequency of the rare allele is 0.38 (PIC value 0.36). We have also studied the frequency of the polymorphism in normolipidaemic and hyperlipidaemic individuals whose apo E protein typing is known. In 39 individuals with type III hyperlipidaemia and the apo E phenotype E2E2, the frequency of the H2 allele is 0.97. In contrast, the frequency of the H2 allele in normolipidaemic individuals with the E2E2 phenotype is closer to that found in the general population. Possible explanations for this are discussed.
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PMID:A common restriction fragment length polymorphism of the human apolipoprotein E gene and its relationship to type III hyperlipidaemia. 288 78

Genetic polymorphism and rare mutants of apolipoproteins occur in humans. The polymorphism of apolipoprotein E (apoE) is controlled by three common alleles, epsilon 2, epsilon 3, and epsilon 4, which code for proteins that differ in lipoprotein receptor binding activity, or in their catabolism in vivo, or both. This may explain the observed significant effects of the apoE alleles on the phenotypic variance of plasma lipoprotein concentrations in different ethnic groups and, moreover, the involvement of apoE alleles in the pathogenesis of multifactorial forms of hyperlipidaemia, for example, hypertriglyceridaemia, familial type III hyperlipidaemia (apoE-2 Arg-158----Cys) and polygenic hypercholesterolaemia (apoE-4 Cys-112----Arg). A further polymorphic gene locus controls the concentrations of the Lp(a) lipoprotein complex in plasma, which may vary from less than 1 mg/dl to greater than 200 mg/dl between different individuals. This lipoprotein contains two different polypeptides, apoB-100 and the Lp(a) glycoprotein. The Lp(a) glycoprotein exhibits genetic polymorphism which is controlled by a series of autosomal alleles at a single locus and which is associated with lipoprotein concentrations in plasma. This suggests that the same gene locus is involved in determining Lp(a) glycoprotein phenotypes and Lp(a) lipoprotein concentrations in plasma. Thus, there is evidence that variability in apolipoprotein genes relates to the normal variance of lipoprotein concentrations in the population and that this variability is a major genetic factor in multifactorial forms of hyperlipidaemia.
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PMID:Apolipoproteins, quantitative lipoprotein traits and multifactorial hyperlipidaemia. 296

The primary structure of apolipoprotein E (apo E) was investigated in seven type III hyperlipoproteinemic patients with the apo E-2/2 phenotype. Six of the patients had identical two-dimensional tryptic peptide maps. These differed from the normal apo E3 map by the altered mobility of a single peptide. Amino acid analysis and sequencing showed that apo E2 in these patients had a substitution of 158 Arg----Cys. The presence of this mutation in six of the seven type III patients confirms that this is the most common form of apo E2. The seventh type III patient had a unique map with a new peptide resulting from a substitution of 136 Arg----Ser. He was heterozygous for this and for the more common apo E2 (158 Arg----Cys) variant. His very low-density lipoprotein contained approximately five times more apo E2 (136 Arg----Ser) than apo E2 (158 Arg----Cys), as determined by cysteamine treatment and peptide mapping. This new apo E2 mutant thus appears to contribute significantly to the patient's hyperlipidemia.
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PMID:Apolipoprotein E2-Christchurch (136 Arg----Ser). New variant of human apolipoprotein E in a patient with type III hyperlipoproteinemia. 303 59

Apolipoproteins AIV, B, E, and the Lp(a) glycoprotein are genetically polymorphic in humans. Three common alleles epsilon 2, epsilon 3 and epsilon 4 control the polymorphism of apolipoprotein E. These code for proteins which differ in functional properties, e.g. receptor binding activity and in vivo catabolism. This explains the significant effect of the apoE gene locus on the variability of plasma lipoprotein concentrations and moreover the implication of apoE alleles in the aetiology of multifactorial forms of hyperlipidaemia e.g. familial type III hyperlipidaemia (apoE2; arg158----cys) and polygenic hypercholesterolaemia (apoE4; cys112----arg). A further gene locus controls the concentrations in plasma of the Lp(a) lipoprotein that is composed of an LDL-like particle containing apoB-100 and the disulphide-bonded Lp(a) glycoprotein. The latter exhibits a genetic size polymorphism (MW approximately 400 kD-700 kD) that is controlled by at least seven autosomal alleles. These alleles at the same time are involved in determining the plasma concentrations of the lipoprotein that range from less than 1 mg/dl to greater than 200 mg/dl. Thus there is evidence that genetic variability in apolipoproteins relates to the variability of lipoprotein concentrations in the population and is implicated in the aetiology of multifactorial hyperlipidaemias.
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PMID:Apolipoprotein polymorphism and multifactorial hyperlipidaemia. 314 88

Phenotypic expressions of apolipoprotein E (apo E) were studied in 94 Japanese patients with non-insulin-dependent diabetes mellitus (NIDDM) and in 91 normal controls. The apo E gene frequencies observed in patients with NIDDM (epsilon 4, 0.101; epsilon 3, 0.824; and epsilon 2, 0.075) were not significantly different from those in normal controls (epsilon 4, 0.093; epsilon 3, 0.863; and epsilon 2, 0.044). Subgrouping the diabetic patients with and without hyperlipidemia, the epsilon 2 allele was significantly more frequent in patients with hypertriglyceridemia. The levels of serum triglyceride, very low density lipoprotein-cholesterol (VLDL-C), and VLDL-triglyceride (VLDL-TG) were significantly higher in patients with the epsilon 2 heterozygote than in those without the epsilon 2 allele (P less than .01). The results suggest that variation in the apo E gene may be one factor related to the hypertriglyceridemia present in patients with NIDDM.
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PMID:Phenotypes of apolipoprotein E and abnormalities in lipid metabolism in patients with non-insulin-dependent diabetes mellitus. 319

The different types of serum lipoproteins, including apolipoprotein E phenotypes, were measured in 50 patients with xanthelasma. Half of them were found to be hyperlipemic. The normolipemic and hyperlipemic groups with xanthelasma were compared with two control groups (one a group of normolipemic patients and another a group of hyperlipemic patients without xanthelasma) selected as homogeneously as possible with regard to age, sex, degree of obesity, and hyperlipemic phenotype. The only significant differences found among the groups, regardless of the presence of hyperlipemia, were the increased levels of total and high-density lipoprotein phospholipids, and lower levels of apolipoprotein B, found in the group with xanthelasmas. The distribution of apolipoprotein E phenotypes was the same in both groups, with slight differences between the normolipemic and hyperlipemic groups. Patients with xanthelasmas showed slight deviations in the metabolism of lipoproteins that require further clarification.
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PMID:Apolipoprotein E phenotypes, lipoprotein composition, and xanthelasmas. 277 5

The relationship between apolipoprotein E (apoE) polymorphism and plasma lipids and hyperlipemia was investigated in 105 male type II diabetics and 111 male nondiabetics. ApoE phenotypes were determined by a one-dimensional rapid flat gel isoelectric focusing method as described previously. The apoE phenotype frequency in diabetics was similar to that in nondiabetics. The frequency of hyperlipemia was higher in diabetics (56.2%) than in nondiabetics (32.4%). It was highest in the apoE3/2 group of diabetics and nondiabetics, followed by the apoE4/3 and apoE3/3 groups in the order described, indicating that the susceptibility to hyperlipemia differs among the apoE phenotype groups. ApoE3/2 diabetics had significantly higher levels of apoE and very-low-density lipoprotein (VLDL) cholesterol (chol)/VLDL triglyceride (TG) ratios than apoE3/3 diabetics. The effects of diabetes mellitus on plasma lipid levels differed among the various apoE phenotype groups: i.e., plasma total chol and low-density lipoprotein (LDL) chol increased only in apoE3/2 and apoE4/3 diabetics and plasma high-density lipoprotein chol decreased only in apoE3/3 diabetics, as compared with the corresponding apoE phenotype groups of nondiabetics, whereas plasma TG, VLDL TG, and VLDL chol increased in the three apoE phenotype diabetics. Furthermore, an increase of apoEII:apoEIII ratio was observed in apoE3/3 diabetics, particularly in those with hypertriglyceridemia. This study has also shown that the increased apoEII:apoEIII ratio is due to increased sialation of apoE based on the study of sialidase digestion of apo VLDL.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Apolipoprotein E polymorphism and hyperlipemia in type II diabetics. 377 Mar 14

The structural gene locus for apolipoprotein E (apo E) is polymorphic. Three common alleles (epsilon 2, epsilon 3, epsilon 4) code for three major isoforms in plasma and determine six apo E phenotypes that may be identified by isoelectric focusing on polyacrylamide. To establish what fraction of the inherited variation in a normal plasma lipid and lipoprotein profile is attributable to the segregation of the common alleles at the apo E gene locus, we have estimated the average apo E allelic effects on plasma cholesterol (C), triglycerides, very low-density lipoprotein (VLDL)-C, VLDL-apo B, low-density lipoprotein (LDL)-C, LDL-apo B, and high-density lipoprotein (HDL)-C in a representative sample of normolipidemic individuals from Ottawa, Canada. Data from published studies were also analyzed by the same statistical procedures. As much as 16% of the genetic variance (8.3% of the total variance) for LDL-C could be accounted for by the apo E gene locus. After correction for differences in age, sex, height, and weight, it was found that the epsilon 2 allele lowered and the epsilon 4 allele raised total cholesterol, LDL-C, and LDL-apo B. No other gene has been identified that contributes as much to normal cholesterol variability. Analysis of these data and those of others also indicates that the apo E locus imparts a differential susceptibility to a variety of factors that promote hyperlipidemia. The hypothesis is proposed that the epsilon 2 allele protects against coronary heart disease (CHD) and, hence, gives a reproductive advantage that is balanced by a predisposition to CHD when the epsilon 2 is combined with a second, independent causative factor to give a reproductive disadvantage. A similar mechanism is proposed for the maintenance of the epsilon 4 allele in the population.
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PMID:Role of the apolipoprotein E polymorphism in determining normal plasma lipid and lipoprotein variation. 398 8


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