Familial transthyretin amyloidosis

What is the cause of familial transthyretin amyloidosis?

Familial transthyretin amyloidosis (FTA) is caused by changes (mutations) in the TTR gene. This gene is responsible for making a protein called transthyretin which transports vitamin A and a hormone called thyroxin to many parts of the body. Mutations in TTR lead to a transthyretin protein that is not made correctly. The faulty protein then folds up to form amyloid. Amyloid builds up in various parts of the body causing nerve and tissue damage.

Most people who have FTA have inherited the TTR mutation from a family member. However, a few people with FTA will have no family history of the disease and have a new (de novo) mutation in the TTR gene.

Last updated on 05-01-20

How is familial transthyretin amyloidosis diagnosed?

The diagnosis of familial transthyretin amyloidosis (FTA) can be difficult because the signs and symptoms of FTA often look like other, more common conditions. Doctors and nurses use a combination of signs and symptoms and laboratory and genetic tests to determine if someone has FTA. Laboratory tests include examination of a biopsy of an affected area, along with genetic testing to look for a mutation in TTR gene.

Last updated on 05-01-20

How is familial transthyretin amyloidosis inherited?

Familial transthyretin amyloidosis (FTA) is inherited in families in an autosomal dominant pattern. This means only one copy of a mutated TTR gene is needed for a person to have the condition. The mutation can be inherited from a parent or can happen by chance for the first time (de novo) in an individual.

Each child of a person with FTA has a 50% chance of inheriting the mutation. Most children who inherit a TTR mutation will develop FTA, although they could be more or less severely affected than their parent. For reasons that are unclear, some people have mutations in the TTR gene and never develop FTA.

Last updated on 05-01-20

What is the long-term outlook for people with familial transthyretin amyloidosis?

The outlook and life expectancy for each person with familial transthyretin amyloidosis (FTA) varies and depends on the TTR gene mutation present, organ(s) involved, and how early a person is diagnosed and treated. Some people whose symptoms begin at a younger age may live for only a few years after diagnosis, while older patients with slowly progressive disease can live for many years. On average, people with FTA typically live for 7-12 years after they are first diagnosed.

The long-term outlook after liver transplant is also influenced by many factors, including the type of amyloid present, nutritional status, age, and how much the brain and heart are involved. Newer medications are now available that help slow the build-up of amyloid and delay symptoms and it is not yet clear how these medications will affect the long-term outlook for people with FTA. People with questions about their personal outlook should speak with their healthcare providers.

Last updated on 05-01-20

How many people have familial transthyretin amyloidosis?

The exact incidence of familial transthyretin amyloidosis is unknown. It is more common in certain parts of Portugal, Sweden, and Japan. The common TTR gene mutation, known as Val30Met, associated with familial transthyretin amyloidosis (FTA) occurs in about 1 in 583 people in some parts of Portugal, compared to about 1 in 100,000 people in the US. A different TTR gene mutation associated with FTA, Val122Ile, is more common in parts of West Africa. While FTA is more common in certain parts of the world, it has been found across all ethnic groups and occurs equally in males and females.

Last updated on 05-01-20

How might familial transthyretin amyloidosis be treated?

There is no treatment available for familial transthyretin amyloidosis (FTA) that reverses damage caused by amyloid deposits, but there are treatments that may prevent or delay progression. Treatment depends on which tissues are affected and how far the disease has progressed.

Liver transplantation is the "gold standard" for treatment for FTA, because it replaces the main source of amyloid. It may slow or halt progression of peripheral neuropathy, but the disease often still progresses in the eyes and brain. Transplantation ideally should be done as early as possible before there are severe neurological problems.

Several medications have been developed that slow the build-up of amyloid along nerves and in other parts of the body. These include tafamidis, diflunsial, and more recently inotersen and patisiran. There are other drugs that are currently under investigation for this condition.

Additional treatments may include heart and/or kidney transplantation, replacement of the liquid part of the eye (vitrectomy) for eye involvement, and carpal tunnel surgery.

Diuretics, medications that remove excess water and salt from the body, are often used to manage congestive heart failure associated with the disease. Other symptoms of FTA are treated as they arise.

Last updated on 05-01-20

Name: Amyloidosis Foundation 7151 N. Main Street Suite 2
Clarkston, MI, 48346, United States
Toll Free: 877-AMYLOID (1-877-269-5643) Email: info@amyloidosis.org Url: http://www.amyloidosis.org/
Name: Amyloidosis Support Groups Inc. 232 Orchard Drive
Wood Dale, IL, 60191, United States
Phone: 630-350-7539 Toll Free: 866-404-7539 Email: info@amyloidosissupport.org Url: https://www.amyloidosissupport.org/
Name: Amyloidosis Australia, Inc. 131-133 Napier Street St. Arnaud,
Victoria, 3478
Australia
Phone: 03 5495 1169 Email: info@amyloidosis.com.au Url: http://www.amyloidosis.com.au/
Plante-Bordeneuve V. Transthyretin familial amyloid polyneuropathy: an update Jl of Neuro. 2018; 265. 976-983. Reference Link Pinto MV, Barreria AA, Bulle AS, Gomes de Freitas MR, et al. Brazilian consensus for diagnosis, management and treatment for transthyretin familial amyloid polyneuropathy Arg Neuropsiquiatr. Sep 2018; 76(9). 609-621. Reference Link

Note, these links are external searches against the National Laboratory of Medicine's drug database. You may need to adjust the search if there are no results found.

Drug Name Generic Name
Vyndaqel; Vyndamax tafamidis meglumine
Onpattro patisiran
Tegsedi Inotersen

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