Amyloidosis is a condition in which an abnormal protein called amyloid builds up in your tissues and organs. When it does, it affects their shape and how they work. Amyloidosis is a serious health problem that can lead to life-threatening organ failure.
Causes and Types of Amyloidosis
Many different proteins can lead to the formation of amyloid deposits, but only a few have been linked to significant health problems. The type of protein and where it collects determines the type of amyloidosis you have. Amyloid deposits may collect throughout your body or in just one area.
There are different types of amyloidosis, including:
Primary (systemic AL) amyloidosis. This occurs without a known cause, but It has been seen in people with a blood cancer called multiple myeloma. This is the most common type of amyloidosis. Systemic means it affects the entire body. The most commonly affected body parts are the kidney, heart, liver, intestines, and certain nerves. AL stands for "amyloid light chains," which is the type of protein responsible for this type of amyloidosis.
Secondary (systemic AA) amyloidosis. This is the result of another chronic inflammatory disease, such as lupus, rheumatoid arthritis, tuberculosis, inflammatory bowel disease (Crohn's disease and ulcerative colitis), and certain cancers. It most commonly affects the spleen, kidneys, liver, adrenal gland, and lymph nodes. AA means the amyloid type A protein causes this type of amyloidosis.
Dialysis-related amyloidosis (DRA). This is more common in older adults and people who have been on dialysis for more than five years. This form of amyloidosis is caused by deposits of beta-2 microglobulin that build up in the blood. Deposits can occur in many different tissues, but most commonly affects bones, joints, and tendons.
Familial, or hereditary, amyloidosis (AF). This is a rare form that is passed down through families. It is caused by an abnormal amyloid transthyretin (TTR) protein, which is made in the liver. This protein is responsible for the most common forms of hereditary amyloidosis.
Senile systemic amyloidosis (SSA). This is caused deposits of normal TTR in the heart and other tissues. It occurs most commonly in older men.
Organ-specific amyloidosis. This is cause deposits of amyloid protein in single organs, including the skin (cutaneous amyloidosis).
While some types of amyloid deposits have been linked to Alzheimer's disease, the brain is rarely involved in systemic (body-wide) amyloidosis.
Risk Factors for Amyloidosis
Men get amyloidosis more often than women. Your risk for amyloidosis increases as you grow older. Amyloidosis affects 15% of patients with a form of cancer called multiple myeloma.
Amyloidosis may also occur in people with end-stage kidney disease who are on dialysis for a long time (see "Dialysis-related amyloidosis" above).