What is amyloidosis?

Amyloidosis is a disease that leads to the buildup of protein in vital organs, which causes these organs to become damaged. Our bodies make several proteins that can cause amyloidosis. In order to treat a patient who has amyloidosis, it’s very important to know the exact protein that is causing the disease.

What are the types of protein that can cause amyloidosis?

These are the most common types of protein that can cause amyloidosis:

AL (light chain) amyloidosis: In amyloidosis of the light chain type, a cell in your bone marrow called the plasma cell makes too much of an abnormal part of your antibodies. Antibodies (also called immunoglobulins) are proteins that normally help you fight infections. However, in AL amyloidosis, the plasma cell is no longer under the normal control of the immune system. The plasma cell continues to make antibodies (not in response to infection), and the antibody protein that is made is abnormal. The abnormal light chain portion of the antibody is not able to leave your body as it normally does in the urine, and instead is deposited into your organs.

Our bodies make 2 light chain proteins, kappa and lambda. Either can cause amyloidosis, but you can only have 1 of these light chain types, not both. Organs that are commonly affected are the heart, kidney, skin, stomach, small and large intestines, nerves, and liver. Sometimes only 1 organ is affected, and other times many are involved.

There is a similar type of amyloidosis that is produced by the heavy chain portion of the antibody called AH amyloidosis. AL or AH amyloidosis can also occur due to a cancer of the plasma cell called multiple myeloma.

ATTR (transthyretin) amyloidosis: Transthyretin is a protein made by the liver to help carry thyroid hormones in your blood. Transthyretin amyloidosis has 2 forms, hereditary and senile:

  • In the hereditary form, there is an error in the DNA that makes the transthyretin protein. This error is passed from one generation to the next and leads to too much of the transthyretin protein. Over time, the transthyretin protein builds up in the organs and causes organ failure. It can take several decades before organ damage is noticeable. This form of transthyretin amyloidosis can affect the heart, nerves, and kidneys.
  • In the senile form, there is no DNA error in the transthyretin gene. Instead, the transthyretin protein itself becomes abnormal and begins to build up in the body over several years. This form of transthyretin amyloidosis usually affects the hearts of men around 80 years of age. Carpal tunnel syndrome can develop several years before cardiac failure and can be an important clue to making this diagnosis.

AA (apo serum amyloid A) amyloidosis: The protein apo serum amyloid A occurs in high levels where inflammation (irritation and swelling) is present in the body. It can cause amyloidosis when high levels of the protein occur for long periods of time. Worldwide, this is the most common type of amyloidosis due to its association with inherited periodic fever syndromes such as Familial Mediterranean Fever. Other chronic (long-term) inflammatory conditions that can cause AA amyloidosis are Crohn’s disease, ulcerative colitis, rheumatoid arthritis, and chronic infections. Organs commonly affected include the kidney and intestines.

What are the signs or symptoms of amyloidosis?

Heart damage:

  • Swelling of the feet or legs
  • Shortness of breath
  • Abnormal heart rhythms
  • Lightheadedness

Kidney damage:

  • Swelling of the feet or legs
  • Excessive bubbles in the urine
  • Urinating less
  • Getting up at night to urinate

Stomach or intestine damage:

  • Bleeding from the rectum
  • Vomiting blood
  • Diarrhea
  • Poor appetite
  • Bloating or excessive gas

Nerve damage:

  • Abnormal sensation in the fingers and toes, which can spread up the arms and legs (foot “falls asleep”)
  • Weakness in the arms or legs
  • Lightheadedness upon standing
  • Diarrhea or constipation

Skin damage:

  • Bruising or bleeding easily
  • Weak fingernails and toenails
  • Rapid hair loss
  • Purple color on the eyelids or around the eyes and other areas of skin folds

Tongue enlargement is rare, but if it occurs, the person should be tested for amyloidosis.

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