Familial dysbetalipoproteinemia

  • Definition
    • Familial dysbetalipoproteinemia is a disorder passed down through families. It causes high amounts of cholesterol and triglycerides in the blood.

  • Alternative Names
    • Type III hyperlipoproteinemia; Deficient or defective apolipoprotein E

  • Causes
    • A genetic defect causes this condition. The defect results in the buildup of large lipoprotein particles that contain both cholesterol and a type of fat called triglycerides. The disease is linked to defects in the gene for apolipoprotein E in many cases.

      Hypothyroidism, obesity, or diabetes can make the condition worse. Risk factors for familial dysbetalipoproteinemia include a family history of the disorder or coronary artery disease.

  • Symptoms
    • Symptoms may not be seen until age 20 or older.

      Yellow deposits of fatty material in the skin called xanthomas may appear on the eyelids, palms of the hands, soles of the feet, or on the tendons of the knees and elbows.

      Other symptoms may include:

      • Chest pain (angina) or other signs of coronary artery disease may be present at a young age
      • Cramping of one or both calves when walking
      • Sores on the toes that do not heal
      • Sudden stroke-like symptoms such as trouble speaking, drooping on one side of the face, weakness of an arm or leg, and loss of balance
  • Exams and Tests
  • Treatment
    • The goal of treatment is to control conditions such as obesity, hypothyroidism, and diabetes.

      Making diet changes to reduce calories, saturated fats, and cholesterol may help lower blood cholesterol.

      If cholesterol and triglyceride levels are still high after you have made diet changes, your health care provider may have you take medicines as well. Medicines to lower blood triglyceride and cholesterol levels include:

      • Bile acid-sequestering resins.
      • Fibrates (gemfibrozil, fenofibrate).
      • Nicotinic acid.
      • Statins.
      • PCSK9 inhibitors, such as alirocumab (Praluent) and evolocumab (Repatha). These represent a newer class of drugs to treat cholesterol.
  • Outlook (Prognosis)
    • People with this condition have a significantly increased risk for coronary artery disease and peripheral vascular disease.

      With treatment, most people are able to greatly reduce their levels of cholesterol and triglycerides.

  • Possible Complications
    • Complications may include:

      • Heart attack
      • Stroke
      • Peripheral vascular disease
      • Intermittent claudication
      • Gangrene of the lower extremities
  • When to Contact a Medical Professional
    • Call your provider if you have been diagnosed with this disorder and:

      • New symptoms develop.
      • Symptoms do not improve with treatment.
      • Symptoms get worse.
  • Prevention
    • Screening the family members of people with this condition may lead to early detection and treatment.

      Getting treated early and limiting other risk factors such as smoking can help prevent early heart attacks, strokes, and blocked blood vessels.

  • References
    • Genest J, Libby P. Lipoprotein disorders and cardiovascular disease. In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald, E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 45.

      Navarese EP, Kolodziejczak M, Schulze V, et al. Effects of proprotein convertase subtilisin/kexin type 9 antibodies in adults with hypercholesterolemia: a systematic review and meta-analysis. Ann Intern Med. 2015;163(1):40-51. PMID: 25915661

      Robinson JG, Farnier M, Krempf M, et al. Efficacy and safety of alirocumab in reducing lipids and cardiovascular events. N Engl J Med. 2015;372(16):1489-1499. PMID: 25773378

      Semenkovich CF. Disorders of lipid metabolism. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 206.