Apolipoprotein E (Heart Disease, Hypercholesterolemia, Hyperbeta-lipoproteinemia)
The ApoE3 allele is the most common of the isoforms, and it is
distinguished by a cysteine at amino acid 112 (112Cys) and by an
arginine at aminoacid 158 (Arg158).
Individuals with the ApoE-4 (112Arg and 158Arg) allele carry an
increased risk of atherosclerotic vascular disease and an increase levels
of total cholesterol and betalipoprotein.
Individuals homozygous for ApoE-2 (112Cys and 158Cys) allele have an
increased risk to develop familial type III hyperlipidemia.
Identification of Apo E isoforms by genetic isotyping has the advantage
over conventional phenotyping because glycosylation of Apo E makes the
phenotypic identification ambiguous.
Apolipoprotein E genotyping is probably indicated in all patients who have
combined elevations of total cholesterol (>260 mg/dl) and triglyceride
(>300 mg/dl) to identify type III hyperlipidemia.
References:
1. Hixson, James E. and D.T. Vernier (1990) Restriction isotyping of
human apolipoprotein E by gene amplification and cleavage with Hha I. J.
Lipid Res. 31:545-8.
2. Utermann, G., A. Hardewig, and F. Zimmer (1984) Apolipoprotein E
phenotypes in patients with myocardial infarction. Hum. Genet. 65:237-41.
3. deKnijff, P and L.M. Havekes. (1996) Apolipoprotein E as a risk for
coronary heart disease: a genetic and molecular biology approach. Cur.
Opinion in Lipid. 7:593
4. Marinetti, G.V. (1990) Disorders of lipoprotein metabolism.
Dyslipoproteinemias. G.V. Marinettii, ed. Plenum Press, New York,
London.
For more information go to National Center for Biotechnology Information
(NCBI). Most abstracts and many full length articles can be printed from this
web site.
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