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.

Links

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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