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?

TTR is a natural protein made mostly by the liver that helps carry the hormone thyroxine and vitamin A around the body. In ATTR amyloidosis, this protein becomes unstable, breaks apart, and deposits in various tissues and organs in the body – most commonly in the heart, kidneys, and nervous system.

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.