Dysbetalipoproteinemia

Dysbetalipoproteinemia (type III hyperlipidemia) is a rare inherited disorder characterized by a defect in the removal of chylomicron and VLDL residues. The underlying disorder is homozygosity for the mutant form of apo E (apo E2), which binds poorly to the liver receptors. As a result, chylomicron residues accumulate as well as cholesterol-rish VLDL (β-VLDL).


 * Clinical manifestations:
 * Various forms of xanthomas:
 * tuberous xanthomas (in 80 %),
 * palmar xantomas (70 %) – are characteritic,
 * tendon xantomas (30 %),
 * eruptive xantomas (rare).
 * Hyperuricaemia and diabetes are observed in about half of patients.
 * Early atherosclerotic changes first affect the lower limbs and coronary arteries (in men before the age of 40, in women before the age of 50).


 * Biochemical findings: Opalescent serum; increased both cholesterol and triacylglycerols:
 * S-cholesterol usually above 7,5 mmol/l, sometimes up to 25 mmol/l, S-triacylglyceroly 2–10 mmol/l, rarely 20 mmol/l.
 * Characteristic appearance of ELFO-lipoproteins: "broad" β-fraction (merging pre-β and β fractions).

There is an abnormal fraction between VLDL and LDL (so-called. β-VLDL) on the polyacrylamide gel. An increase in the cholesterol/triacylglycerol ration to >0.30, a decrease in HDL and LDL cholesterol and, conversely, an increase in VLDL, IDL and chylomicron residues are characteristic.

related articles

 * Disorders of lipid metabolism (detailed)
 * Lipoproteins

Source

 * MASOPUST, Jaroslav – PRŮŠA, Richard. Patobiochemie metabolických drah. 2. vydání. Univerzita Karlova, 2004. 208 s.

Reference
BURTIS, Carl A, Edward R ASHWOOD and David E BRUNS. Tietz textbook of clinical chemistry and molecular diagnostics. 4th edition. St. Louis, Mo: Elsevier Saunders, 2006. 2412 pp. 930. ISBN 978-0-7216-0189-2.

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