Types of amyloidosis

We focus mainly on the ATTR types, this is because it’s the one that affects people in Ireland most. There are other types like (AL or AA) but we don’t focus on them too much. It’s best to find another resource for information on those. Though do get in touch with us, if you think you have another type, we could help sign post you to other resources.

Some types of amyloidosis are life threatening and others are less harmful. The type of amyloidosis depends on the type of protein that accumulates.

Hereditary ATTR Amyloidosis

Hereditary ATTR amyloidosis is an inherited disease, where the body makes a mutant form of a protein called “transthyretin.” Transthyretin is abbreviated “TTR” and is the reason this disease is called familial ATTR amyloidosis.

While everyone produces transthyretin, the mutated form is more likely to form into amyloid fibrils. Many different mutations have been identified; one of the most common is called Thr60Ala is one type of ATTR amyloidosis with a specific origin in Donegal, in the north west of Ireland. H90D is a variant also found in Ireland, predominantly in Cork. Another is “V-122-I” and is particularly common in individuals of African descent.

Hereditary ATTR amyloidosis most commonly affects the heart and nerves. Other organ involvement may occur, but is uncommon. Though it is a very serious disease, the prognosis for hereditary ATTR amyloidosis is overall better than AL amyloidosis, as it usually progresses at a slower rate.

Wild-Type (Senile) ATTR Amyloidosis

Wild-type (senile) ATTR amyloidosis is similar to hereditary ATTR amyloidosis, except the protein that is deposited is the normal, non-mutated transthyretin protein. The normal transthyretin protein is less prone to forming amyloid deposits than the mutated form.

As a result, patients only develop the disease in older age, usually at 65 years of age or older. Because amyloid deposits accumulate slowly in this form of the disease, the prognosis is generally better than AL (primary) amyloidosis and hereditary ATTR amyloidosis.

A note about other types

There are other types outside ATTR amyloidosis. Though we don’t go into the detail of those here, because they’re quite different. Most people that we know of in Ireland are impacted by ATTR, but there is a community of people that suffer other types. Get in touch with us if you’d like guidance on where to find information on the other types (like AL or AA).

Next chapter: questions to help newly diagnosed patients, click here to read on