Amyloid Fibrils Formation
Amyloid Fibrils Formation

What is amyloidosis?

Amyloidosis (am-uh-loy-doh-sis) is a protein disorder. In this disease, proteins change shape (misfold), then clump together and form amyloid fibrils which deposit in organs. As amyloid fibrils build up, the tissues and organs may not work as well as they should.

Our bodies make several proteins that can cause amyloidosis. To choose the right treatment, it is very important to know the exact protein that is causing the disease. The two most common types are light chain (AL) and transthyretin (ATTR) amyloidosis.

What is Amyloid Transthyretin amyloidosis (ATTR amyloidosis)?

Transthyretin (trans-thigh-re-tin), also called TTR, is a protein made by the liver that helps carry thyroid hormone and vitamin A in the blood. Normally, TTR is made up of four identical parts. However, in ATTR amyloidosis, the protein becomes unstable, breaks apart, and deposits in the heart and/or the nerves.

There are two types of ATTR Amyloidosis:

Hereditary (familial) ATTR amyloidosis. In this form, there is a change (mutation) in the DNA that is inherited and can be passed from one generation to the next. This makes the TTR protein more unstable and more likely to form amyloid fibrils. Different mutations lead to different symptoms — some may affect the nerves; some may affect the heart; and some may affect both.

Wild-type ATTR amyloidosis. Unlike hereditary ATTR amyloidosis, wild-type does not involve abnormal DNA and cannot be passed on to family members. Instead, as you get older, the normal TTR protein becomes unstable, misfolds and forms amyloid fibrils.

These ATTR amyloid fibrils usually deposit in:

  • The wrist, in a narrow pathway called the carpal tunnel. This can cause carpal tunnel syndrome, which causes your hand and arm to become numb and tingle.
  • The spinal canal, which can cause narrowing of the spinal column (spinal stenosis).
  • The heart, which can cause heart failure and/or an irregular heart rhythm called atrial fibrillation.
  • Carpal tunnel syndrome and spinal stenosis can develop several years before heart failure.

What are the signs and symptoms of ATTR amyloidosis?

ATTR amyloidosis can affect many organs. Symptoms depend on the organs that are involved.

Symptoms indicating the arms are affected include:

  • Carpal tunnel syndrome
  • Numbness, burning and/or tingling (peripheral neuropathy)

Symptoms indicating the back is affected include:

  • Lumbar spinal stenosis

Symptoms indicating the legs are affected include:

  • Swelling of the feet or legs
  • Numbness, burning and/or tingling (peripheral neuropathy)
  • Leg weakness

Symptoms indicating the head and neck are affected include:

  • Eye floaters (vitreous opacities)
  • Lightheadedness upon standing

Symptoms indicating the heart and lungs are affected include:

  • Shortness of breath
  • Palpitations
  • Chest pain
  • Fatigue

Symptoms indicating the stomach or intestines are affected include:

  • Poor appetite
  • Bloating or excessive gas
  • Diarrhea or constipation

Amyloidosis ATTR Symptoms Chart

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