For Patients – Amyloidosis Types

Stomach biopsy. Photo provided by Dr. Stephen Cook.

What is amyloidosis?

Amyloidosis refers to a group of diseases that are caused by the abnormal deposition of certain proteins (amyloid fibrils) in tissues throughout the body. The specific type of protein involved determines the type of amyloidosis. Many different types of amyloidosis have been identified, each with their own symptoms and treatment. Below is a list of the most common.

Cardiac H&E Stain. Photo provided by Dr. Philip Ursell.

Amyloid types

Primary (AL) amyloidosis

Primary amyloidosis is the most common type of amyloidosis in the United States. Primary amyloidosis develops when plasma cells in the bone marrow produce an abnormal protein that forms amyloid deposits throughout the body. Any organ of the body can be involved, including the kidneys, nerves, heart, and gastrointestinal tract. Primary amyloidosis is often associated with another bone marrow disease, multiple myeloma. Stem cell transplant and medications including chemotherapy may be treatment options for patients with primary amyloidosis.

Secondary (AA) amyloidosis

Secondary amyloidosis develops in patients with a chronic inflammatory condition such as infection or rheumatoid arthritis. Chronic inflammation leads to increased levels of a protein called SAA, which forms amyloid fibrils and deposits in organs. The most common site of involvement in secondary amyloidosis is the kidney. Treatment is aimed at the underlying condition causing the inflammation.

Familial amyloidosis

Familial amyloidosis is an inherited condition passed down in an autosomal dominant pattern, meaning each child of an affected parent has a 50% chance of inheriting the abnormal gene. The genetic mutations associated with familial amyloidosis most often cause an abnormality in a protein called transthyretin (TTR). The abnormal TTR proteins form amyloid fibrils that deposit in organs throughout the body.

Age-related (senile) amyloidosis

Senile amyloidosis occurs when otherwise normal TTR proteins form amyloid fibrils that deposit in the heart and other organs. Senile amyloidosis primarily affects older men.