What are the different types of amyloidosis?

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What are the different types of amyloidosis?

Proteins are long molecules that stretch out like chains. Your body uses them for energy, internal chemical reactions, sending messages between different body systems and more. But there’s a catch: Your cells can only use these chains if they have the right shape. Protein misfolding disorders like amyloidosis distort and twist proteins so they won’t work properly.

When this happens to enough proteins, they can tangle together and your body can’t use them. With nowhere to go, the tangled proteins bunch up, stick together and then get stuck in different places throughout your body.

Amyloidosis can affect many systems throughout your body, especially your heart. There are three main types of amyloidosis that affect your heart (other types can also affect your heart, but that only happens in rare instances).

AL (light chain)

Your body uses light chains as part of your immune system, which defends against germs like viruses and bacteria. AL amyloidosis happens when cells in your bone marrow malfunction and make too many light chains. This can happen on its own or because of certain types of blood or immune system cancers. Diagnosis of this type of amyloidosis typically happens after age 50.

ATTR

Transthyretin (often abbreviated TTR) is a protein that helps carry certain chemicals throughout your body. It gets its name from how it transports thyroid hormone and retinol (also known as vitamin A). An older name for this protein that’s no longer in use is thyroxine-binding prealbumin (TBPA).

Amyloid TTR (ATTR) can have a wide range of symptoms, and it can appear as early as age 20 or as late as age 70. It has two main sub-types:

  • Hereditary. This sub-type of ATTR is genetic, meaning you inherit it from one or both of your biological parents.
  • Wild-type. This happens when TTR begins misfolding on its own without any genetic mutation. This is usually something that happens when you are over the age of 60. This condition was once known as senile systemic amyloidosis or senile cardiac amyloidosis, but these names are no longer commonly used.

People who are on dialysis for several years have a higher risk of developing amyloidosis. That’s because dialysis typically doesn’t filter out β2 (beta-2) microglobulin proteins. These proteins, often abbreviated β2Ms, build up in your heart and other areas of your body.

Rare types of cardiac amyloidosis

There are several other subtypes of cardiac amyloidosis, but overall they are very rare.

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