Amyloidosis, also known as amyloid disease, is a rare group of disorders in which abnormal proteins called amyloid build up in tissues and organs. This abnormal protein deposit can interfere with the normal structure and function of affected organs. Amyloid deposits may affect the heart, kidneys, liver, digestive system, nerves, skin, joints, spleen, or other organs. In some people, amyloidosis affects only one organ, while in others it can involve several organs at the same time. The severity of amyloidosis varies widely. Some forms progress slowly, whereas others can cause serious or life-threatening organ damage if not diagnosed and treated promptly.
AL amyloidosis, also called light-chain amyloidosis, is the most common type of systemic amyloidosis. It occurs when abnormal plasma cells in the bone marrow produce excessive amounts of abnormal antibody light-chain proteins. These proteins can form amyloid deposits in organs such as the heart, kidneys, nerves, digestive tract and liver. AL amyloidosis can sometimes occur in association with plasma-cell disorders such as multiple myeloma.
AA amyloidosis develops when amyloid deposits form from the serum amyloid A (SAA) protein. It is usually associated with long-standing inflammatory or infectious diseases, such as certain autoimmune disorders and chronic infections.
Hereditary amyloidosis results from inherited genetic changes that cause certain proteins to become unstable and form amyloid deposits. The liver, nerves, heart and kidneys may be affected depending on the specific genetic mutation.
Wild-type transthyretin (ATTR) amyloidosis occurs when a normal protein called transthyretin becomes unstable and forms amyloid deposits. It primarily affects older adults and commonly involves the heart. It may also be associated with conditions such as carpal tunnel syndrome.
In localized amyloidosis, amyloid deposits are limited mainly to one area or organ rather than being widely distributed throughout the body. The skin, lungs, bladder and other tissues can sometimes be affected.
When amyloid deposits affect the heart, they can make the heart muscle stiff and interfere with its ability to pump and fill properly. Possible symptoms include:
Shortness of breath
Fatigue
Swelling of the legs and ankles
Irregular heartbeat
Chest discomfort
Dizziness or fainting
Cardiac amyloidosis can lead to heart failure and abnormal heart rhythms.
Amyloidosis can be difficult to diagnose because its symptoms can resemble those of many other diseases. A doctor may begin with a medical history, physical examination and blood and urine tests. Diagnostic tests may include:
A biopsy may be required to confirm amyloid deposits. A small tissue sample may be taken from an affected organ or, in some situations, from another site such as abdominal fat. The tissue is examined under a microscope and may undergo specialized testing to determine the type of amyloid protein. Accurate amyloid typing is important because treatment differs substantially between the various forms.
Genetic testing may be recommended when hereditary amyloidosis is suspected or when a particular form of ATTR amyloidosis needs to be distinguished from wild-type disease.
Treatment depends on the type of amyloidosis, the organs affected and the severity of the disease. The main goals are to stop or reduce the production of the abnormal protein, prevent further amyloid deposition and protect organ function.
Treatment generally focuses on abnormal plasma cells that produce amyloid-forming light chains. Depending on the individual’s condition, treatment may include:
Plasma-cell-directed medicines
Chemotherapy-based treatment
Targeted therapies
Immunotherapy or monoclonal antibody treatment
Autologous stem cell transplantation in selected patients
Treatment focuses on controlling the underlying inflammatory or infectious disease responsible for the excessive production of serum amyloid A.
Controlling the underlying condition can reduce further amyloid production and deposition.
ATTR amyloidosis may be treated with medicines that help stabilize transthyretin or reduce its production, depending on the type and clinical situation. Supportive treatment may also be required for heart failure, nerve problems and other complications.
See a healthcare professional if you have persistent or unexplained symptoms such as swelling, shortness of breath, unexplained weight loss, numbness or tingling, persistent digestive problems, or abnormal kidney or heart test results. Because amyloidosis is uncommon and may resemble other conditions, unexplained involvement of multiple organs may require evaluation by a specialist.
Some forms of amyloidosis cannot currently be prevented, particularly hereditary forms. However, the risk of developing AA amyloidosis may be reduced by effective diagnosis and treatment of chronic inflammatory or infectious diseases that can cause it. For hereditary amyloidosis, genetic counseling may help affected families understand inheritance and available testing options.
Amyloidosis itself is not cancer. However, AL amyloidosis can be associated with abnormal plasma-cell disorders, including multiple myeloma. The relationship depends on the specific type of amyloidosis.
Some forms can be treated very effectively, particularly when diagnosed early. Treatment may stop or substantially reduce the production of amyloid-forming proteins and help preserve organ function. Whether the disease can be completely eliminated depends on its type and individual circumstances.
Some forms are hereditary, meaning they result from inherited genetic mutations. Other forms, such as AL, AA and wild-type ATTR amyloidosis, are generally not inherited in the same way.
The heart and kidneys are commonly affected in systemic amyloidosis, although the nerves, digestive system, liver, skin and other organs can also be involved.
Yes. Cardiac amyloidosis occurs when amyloid deposits accumulate in the heart. It can cause heart muscle stiffness, heart failure and abnormal heart rhythms.
Medical Disclaimer: This article is intended for general educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. If you have symptoms or have been diagnosed with amyloidosis, consult a qualified healthcare professional for an individualized evaluation and treatment plan.
