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(Amyloid Light Chain)
Amyloidosis is a buildup of abnormal proteins called amyloids. Amyloid proteins cannot be broken down by the body and eventually build up in certain tissue of the body. A buildup in organs like the heart, liver, kidneys and nerves can lead to symptoms and life-threatening complications.
There are several types of amyloidosis based on the specific type of protein that is involved. The most common type of amyloidosis is AL or light chain amyloidosis. It is an abnormal form of antibody proteins.
AL amyloidosis is caused by problems with certain cells in the bone marrow. These cells make blood products including a type of protein called antibodies or immunoglobulins. Certain conditions will interfere with how the antibody proteins develop. The antibodies misfold which leads to amyloid pieces. The amyloids travel in the blood and deposit into tissue and organs. Since the body cannot break down the amyloids, they build up in the tissue. Eventually the amyloids cause tissue damage and interfere with how it functions.
AL amyloidosis is most common in people 50-80 years of age. It is also more common in men than women. Conditions that may be associated with AL amyloidosis include:
- Multiple myeloma
- Waldenstrom macroglobulinemia
There may also be a link between AL amyloidosis and exposure to certain weed killers or Agent Orange.
Symptoms can vary from person to person. Some common symptoms may include:
- Weight loss
- Shortness of breath
Other symptoms will depend on the extent of the disease and the organ that is affected. For example:
- Kidney deposits can cause leaking of protein with swelling in the legs, belly, and arms. Kidney deposits can eventually lead to kidney failure .
- Heart deposits can cause stiffness in the heart which can lead to heart failure with shortness of breath even with minor activities. Heart deposits may also cause abnormal rhythms of the heart.
- Digestive system deposits can lead to nausea, diarrhea, loss of appetite, or feeling full even after eating small amounts. They can also result in an enlarger liver.
- Deposits in nerves of hands or feet can cause tingling, pain, or numbness.
- Deposits in nerves that control body functions like blood pressure and heart rate can cause abnormalities that result in light-headedness (dizziness).
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Deposits in other tissue can also lead to symptoms such as:
- Carpal tunnel—from deposits in the wrist
- Enlarged tongue
- Restriction in shoulder movement because of swelling in the joint
You will be asked about your symptoms and medical history. A physical exam will be done. The doctor may do further testing if you have organ-specific symptoms like the ones listed above with no other obvious cause.
Biopsy of the affected tissue or bone marrow can confirm AL amyloidosis diagnosis.
Amyloid testing can be also be done by blood and urine testing
Other testing may include:
- Blood tests—to look for abnormal antibodies and abnormal organ function
- Urine tests—that test for protein in the urine
- Serum amyloid P component (SAP) scintigraphy—test to see the location of amyloid deposits
- Electrocardiography or echocardiogram if cardiac involvement is suspected
There is no cure for any form of amyloidosis. Treatment is focused on slowing the creation of amyloids and managing any organ changes it has caused. Treatment options to slow or stop the development of amyloids include:
Certain medications can target and destroy the bone marrow cells that are creating amyloids. This will help slow or stop the creation of new amyloids. These medications have been shown to be more effective when used in combination instead of as individual medication. Categories of medication may include:
- Chemotherapy medications
- Proteasome inhibitors
The medication may be given by pill, injection, or through a catheter.
Stem Cell Transplantation
Stem cells are immature cells found in the bone marrow that will eventually develop into blood cells. Some of these blood cells will eventually lead to amyloids. A stem cell transplant replaces current stem cells with healthy stem cells from a donor. It may be used to treat bone marrow conditions associated with AL amyloidosis. Not everyone with AL amyloidosis will benefit from this treatment.
Amyloidosis is rarely found until it has begun to affect how organs are working. Treatment may require support to reduce injury to the organ or symptoms. Exact treatment steps will depend on the severity of injury and which organs are affected. Potential supportive care steps include:
- Nutritional support—amyloids can affect the digestive system and interfere with how well nutrients are absorbed
- Dialysis—to relieve stress on kidneys
- Fluid management—to relieve stress on heart or kidneys, reduce swelling. May be done with dietary changes and/or medications.
- Medication—to help manage symptoms like pain, diarrhea, or constipation
- Surgery or radiation to reduce the size of the deposits.
- Hospice—to relieve pain and suffering from progressively fatal complications
Early treatment helps to decrease damage to the organs.
Genetic and Rare Diseases Information Center
Canadian Organization for Rare Disorders
The Kidney Foundation of Canada
AL Amyloidosis. Amyloidosis Foundation website. Available at: http://www.amyloidosis.org/facts/al/#treatment. Accessed August 23, 2017.
Amyloid light chain (AL) amyloidosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114350/Amyloid-light-chain-AL-amyloidosis . Updated July 6, 2016. Accessed September 19, 2017.
Cardiac amyloidosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T912561/Cardiac-amyloidosis . Updated April 20, 2017. Accessed September 19, 2017.
National Organization for Rare Disorders. A physician's guide to amyloidosis. National Organization for Rare Disorders website. Available at: https://rarediseases.org/rare-diseases/amyloidosis/. Published 2016. Accessed September 19, 2017.
What is amyloidosis? Boston University website. Available at: http://www.bu.edu/amyloid/about/what/. Accessed September 19, 2017.
- Reviewer: EBSCO Medical Review Board Michael Woods, MD, FAAP
- Review Date: 09/2018
- Update Date: 12/30/2015