What Is Amyloidosis?
Amyloidosis (am-uh-loy-doh-sis) is a disease that occurs when an abnormal protein (amyloid) builds up in the tissues and organs of the body, causing them to not work as they should.
Our bodies make several proteins that can cause amyloidosis, and one of the two most common types is transthyretin (TTR).
What is ATTR (transthyretin) amyloidosis?
There are two types of ATTR amyloidosis:
Hereditary (hATTR) amyloidosis
In this type, a mutation in the individual’s DNA makes the TTR protein more unstable, and this is then passed to subsequent generations. There are more than 120 identified mutations affecting different organs or nerves: or both.
Wild-type (wtATTR) amyloidosis
Unlike hereditary type, wild-type does not involve abnormal DNA and therefore cannot be passed to family members. Instead, the normal TTR protein becomes unstable as you age.
AL Amyloidosis (Amyloidosis Light Chain)
AL amyloidosis (amyloid light chain or primary amyloidosis) is a rare disease that happens when abnormal light chain proteins in your body gather on your organs such as the kidneys, the gastrointestinal tract, the heart, or the nervous system.
- Although approximately 10% to 15% of people with myeloma will have or develop AL amyloidosis, it’s rare for people with amyloidosis to develop myeloma.
- AL amyloidosis is usually treated with chemotherapy, using the same drugs that are used to treat myeloma.
AA Amyloidosis
AA amyloidosis occurs as a reaction to another illness, such as a chronic inflammatory disease or a chronic infection. Infections and inflammation cause the liver to produce a protein called SAA (serum amyloid A protein) at high levels. This is a normal reaction.
When inflammation goes on for a very long period of time, a small portion of the SAA protein, called AA protein, will separate from SAA and deposit in tissues as AA amyloid. Normally after an inflammatory reaction, the whole SAA protein is broken down to its amino acid components and recycled, as happens with all proteins. It is not known why in some individuals a partial breakdown of SAA to AA occurs.