Amyloidosis

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Amyloidosis facts

  • Amyloidosis is a disorder resulting from abnormal protein (amyloid) deposits in body tissues.
  • Amyloidosis can occur as an isolated disease or as a result of another illness.
  • Symptoms in patients with amyloidosis result from abnormal functioning of the particular organs involved.
  • Diagnosis of amyloidosis is made with a biopsy of involved tissue.
  • Treatment options for amyloidosis depend on the type of amyloidosis and involve correcting organ failure and treating any underlying conditions.

What is amyloidosis?

Amyloidosis is a group of diseases that result from the abnormal deposition in various tissues of the body of a particular protein called amyloid. Depending on the structure of the particular amyloid, the protein can accumulate in an isolated tissue or be widespread, affecting numerous organs and tissues. Amyloid protein can be deposited in a localized area and may not be harmful or only affect a single tissue of the body impairing its function. This form of amyloidosis is called localized amyloidosis. Amyloidosis that affects many tissues throughout the body is referred to as systemic amyloidosis. Systemic amyloidosis can cause serious changes in virtually any organ of the body.

Amyloidosis can occur as its own entity (primary amyloidosis) or "secondarily" as a result of another illness, including chronic infections (such as tuberculosis or osteomyelitis), or chronic inflammatory diseases (such as rheumatoid arthritis and ankylosing spondylitis). Amyloidosis can also be localized to a specific body area from aging. This localized form of amyloidosis does not have systemic implications for the rest of the body. The protein that deposits in the brain of patients with Alzheimer's disease is a form of amyloid.

Systemic amyloidosis has been classified into three major types that are very different from each other. These are distinguished by a two-letter code that begins with an A (for amyloid). The second letter of the code stands for the protein that accumulates in the tissues in that particular type of amyloidosis. The types of systemic amyloidosis are currently categorized as primary (AL), secondary (AA), and hereditary (ATTR, AApoAI, AApoAII, AGel, ALys, AFib).

In addition, other forms of amyloidosis include beta-2 microglobulin amyloidosis and localized amyloidoses.

Primary amyloidosis

Primary amyloidosis, or AL, occurs when a specialized cell in the bone marrow (plasma cell) spontaneously overproduces a particular protein portion of an antibody called the light chain. (This is why it is coded as AL.) The deposits in the tissues of people with primary amyloidosis are AL proteins. Primary amyloidosis can occur with a bone marrow cancer of plasma cells called multiple myeloma (fewer than 20% of AL patients). Primary amyloid is not associated with any other diseases but is a disease entity of its own, conventionally requiring chemotherapy treatment. Researchers at the Mayo Clinic in Rochester, Minn., and Boston University in Boston, Mass., have demonstrated benefits from stem-cell transplantation, harvesting patients' own stem cells to treat primary amyloidosis.

Secondary amyloidosis

When amyloidosis occurs "secondarily" as a result of another illness, such as chronic infections (for example, tuberculosis or osteomyelitis) or chronic inflammatory diseases (for example, rheumatoid arthritis and ankylosing spondylitis), the condition is referred to as secondary amyloidosis or AA. The amyloid tissue deposits in secondary amyloidosis are AA proteins. The treatment of patients' secondary amyloidosis is directed at treating the underlying illness in that particular patient.

Familial amyloidosis

Familial amyloidosis (ATTR, AApoAI, AApoAII, AGel, ALys, AFib) is a rare form of inherited amyloidosis. The amyloid deposits in most familial amyloidosis are composed of the protein transthyretin, or TTR, which is made in the liver. Familial amyloidosis is an inherited autosomal dominant in genetics terminology. This means that for the offspring of a person with the condition, there is a 50% chance of inheriting it. This form of amyloidosis is also referred to as hereditary amyloidosis.

Beta-2 microglobulin amyloidosis

Beta-2 microglobulin amyloidosis occurs when amyloid deposits develop in patients on dialysis with longstanding kidney failure. The amyloid deposits are composed of beta-2 microglobulin protein and are often found around joints.

Localized amyloidoses

The many forms of localized amyloidosis are a result of amyloid deposits in specific areas of the body and are distinct from systemic forms of amyloidosis that deposit amyloid throughout the body. Localized amyloid deposits occur in the brain from Alzheimer's disease. In various tissues, often with aging, amyloid can be locally produced and deposited to cause tissue injury. Prions are infectious amyloid proteins that transmit the diseases kuru, Creutzfeldt-Jakob disease, fatal familial insomnia, and Gerstmann-Straussler-Scheinker syndrome.

Medically Reviewed by a Doctor on 10/10/2012

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Amyloidosis Treatment

There is no cure for amyloidosis. Your doctor will prescribe treatments to suppress the development of the amyloid-forming protein, and to manage your symptoms. If amyloidosis is related to another condition, then treatment will include targeting that underlying condition.

Specific treatment depends on what type of amyloidosis you have and how many organs are affected.

  • Stem cell transplant can help remove the substance that leads to amyloid formation in those with primary AL amyloidosis and have no more than two major organs damaged. Chemotherapy medicines are used to treat other patients with primary AL amyloidosis.
  • Powerful anti-inflammatory medicines called steroids, which fight inflammation, are used to treat secondary AA amyloidosis.
  • Liver transplant may stop the disease in those with hereditary amyloidosis.
  • A kidney or heart transplant may also be recommended.

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