Amyloidosis is a group of disorders characterized by the abnormal accumulation of misfolded proteins, known as amyloid, in body tissues and organs. These protein deposits can interfere with normal organ function. Amyloidosis does not affect all individuals in the same way and may involve the heart, kidneys, liver, spleen, nervous system, or other tissues.
The process underlying amyloidosis often begins in the bone marrow, where certain proteins—frequently components of antibodies—are produced. In amyloidosis, these proteins are not adequately broken down and instead aggregate and deposit in tissues throughout the body.
Clinical signs and symptoms vary depending on the organs involved. Commonly reported features include swelling of the lower extremities, fatigue, weakness, shortness of breath, numbness or tingling in the hands or feet, unintended weight loss, enlargement of the tongue, irregular heart rhythm, difficulty swallowing, purplish discoloration around the eyes, skin changes such as thickening or easy bruising, and the presence of protein in the urine.
Amyloidosis is generally classified into three main forms:
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Primary amyloidosis, which occurs independently of other known diseases and has no clearly identified cause. It may affect multiple organs, including the heart, kidneys, liver, spleen, nerves, gastrointestinal tract, skin, tongue, and blood vessels.
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Secondary amyloidosis, which develops in association with chronic inflammatory conditions or persistent infections. This form most commonly involves the kidneys, liver, spleen, and lymph nodes, though other organs may also be affected. Disease progression may be influenced by management of the underlying inflammatory condition.
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Familial amyloidosis, an inherited form caused by genetic mutations that affect protein structure. This type often involves the liver, nervous system, heart, and kidneys.
