Transthyretin Familial Amyloid Polyneuropathy

What Is Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP)?

TTR-FAP is a disease that affects your nervous system. It causes too much of a protein called amyloid to build up in your body's organs and tissues. It's a progressive disease, which means it gets worse over time.

The only treatment that can stop the progress of TTR-FAP and help you live longer is a liver transplant.

But there are other treatments, including medicine and changes in your diet, that can help ease many of the symptoms. Researchers are also testing new drugs that slow the growth of the unwanted protein.

It's important to reach out to family and friends to talk about any worries you have and get the emotional support you need.

When you have TTR-FAP, you may develop a variety of symptoms when too much amyloid protein starts to collect in the nerves that branch out from your brain and spinal cord. This can affect your senses. For instance, you may be less likely to feel pain or heat, or have trouble walking. Or it could affect your hearing or vision.

This protein also gathers in the nerves that control important actions in your body, like blood pressure, heart rate, and digestion. You may have trouble going to the bathroom or having sex, or you may sweat too much. Your heart may beat too fast or too slowly.

The most serious symptoms -- and the ones that are most life-threatening -- are an enlarged heart and an irregular heartbeat.

TTR-FAP can affect people of almost any age, from their 30s to 50s or even later.

Your doctor might also use the word "amyloidosis" when talking about the condition. That's because TTR-FAP is one of a group of diseases also known by that name.

Causes

As the name suggests, transthyretin familial amyloid polyneuropathy runs in families. If you have it, you got it from genes your parents passed to you.

It's most common in people of Japanese, Portuguese, or Swedish ancestry.

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Symptoms

Because TTR-FAP can affect a number of organs and systems in your body, it can have a lot of different symptoms. The most serious problems are heart enlargement and irregular heartbeats, the cause of death in many people with TTR-FAP.

You might have numbness, tingling, and swelling in your hands and feet. Or you could have problems like diarrhea, constipation, feeling full as soon as you start eating, and trouble peeing. You might also feel very tired.

Some eye problems you could get include:

Getting a Diagnosis

If you know that TTR-FAP runs in your family, your doctor will probably suggest you get a DNA test to see if you have the gene that causes it. He checks a sample of your blood, cheek cells, or skin.

It can be tough to diagnose TTR-FAP. Your doctor will ask you about your health history to get clues, including:

  • Have you or anyone in your family had heart failure or thickening of the heart muscle?
  • Do you feel numbness or tingling in your hands or feet?
  • Do you have digestive problems such as diarrhea or constipation?
  • Are you having trouble controlling your bladder?
  • Do you get dizzy when standing up or stretching?
  • Have you had any eye or vision problems?

Your doctor may want to do tests related to symptoms you have, too, especially for your nerves and heart.

Blood and urine tests. These simple lab tests will sometimes show if there's too much protein in your body.

Tissue biopsy. This is the main test to diagnose TTR-FAP. Your doctor will take a little bit of tissue from your body, often a small piece of fat from your belly or side. This is quick and doesn't need a hospital stay. The doctor numbs the skin on your stomach and uses a needle to pull out some fat cells. Then a lab tests them.

Questions for Your Doctor

  • Will my symptoms keep getting worse?
  • What treatments are best for me now? Is there a clinical trial that I should think about?
  • Do these treatments have side effects? What can I do about them?
  • How do we check on my progress? Are there new symptoms I should watch for?
  • How often should I see you?
  • Should I add my name to a transplant or disease registry?

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Treatment

Treatment of TTR-FAP depends on your symptoms and how far your condition has developed. The goal of some treatment is to ease the symptoms that are caused when too much amyloid gathers in your organs.

For instance, if you're having problems with your heart or kidneys, you may have a buildup of fluid in your body. Your doctor may prescribe a pill that helps you get rid of unneeded water.

There are also medications you can take if you have digestive problems such as diarrhea or a feeling of fullness.

Researchers are working to develop new drugs that get at the source of your symptoms by preventing amyloid deposits from forming. One drug, tafamidis, is approved in Europe to treat TTR-FAP but not in the U.S.

Another drug, diflunisal, is an anti-inflammatory that has been used to treat arthritis and has been shown in some studies to help keep the amyloid deposits from forming.

Most of the amyloid proteins that cause TTR-FAP are made in the liver, so your doctor may suggest you get a liver transplant. A new liver will let your body make normal proteins instead.

If your doctor recommends a liver transplant, it's best to have it done in the early stages of the disease, before protein deposits have done too much damage to your nerves or heart. If you already have complications from TTR-FAP, such as heart, digestive, or eye problems, these problems often progress even after you get a liver transplant.

A liver transplant is major surgery. First, you'll need to get on a waiting list for a donor. Your new liver will come from someone who recently died and has the same blood type and a similar body size as yours. When donor livers are available, they go to the sickest people on the waiting list.

You may need to stay in the hospital for up to 3 weeks after your surgery. It could take you 6 months to a year before you can return to your regular lifestyle. After your transplant, you'll need to take drugs that prevent your body from rejecting the new liver.

If you're considering a transplant, you'll need a lot of emotional support. Ask your doctor about support groups that have people facing the same concerns as you. Also ask about educational workshops that can explain what to expect before and after a transplant.

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Taking Care of Yourself

You can take lots of steps on your own that can help bring relief. If you have digestive problems, you may want to change your diet. For example, fiber -- found in fruits, vegetables, and whole-grain foods -- can help with constipation.

For heart or kidney problems, you may want to:

  • Cut back on salt, to help keep swelling in check.
  • Wear elastic stockings, to help blood flow back up from your legs.
  • Raise your legs when sitting or lying down, also to control swelling.

Try a warm-water foot massager before bed to help with tingling and burning in your feet.

What to Expect

Although the disease continues to progress, some TTR-FAP symptoms can be controlled and treated. It may take up to 12 to 24 months for relief, but eventually feelings of weakness and numbness may get better.

A liver transplant can stop your symptoms from getting worse, and it's the only treatment that can add years to your life. Studies show that 75% of people with TTR-FAP who get it live 5 years or more after the surgery.

Transplants are less successful if you've already had too much damage to your nerves and your heart from the disease. If that's the case, your disease may get worse even with a new liver. transplant.

It's important to turn to family and friends for support to help you keep up the best possible quality of life. Counseling can also help you with the emotional challenges of living with TTR-FAP.

Getting Support

To learn more about TTR-FAP, visit the web site of theAmyloidosis Foundation. It tells you how to contact support groups and has links to clinical trials.

WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on July 29, 2014

Sources

SOURCES:

Adams, D. Presse Medicale, September 2012.

Amyloidosis Support Groups Inc: "Amyloidosis Awareness."

Genetics Home Reference: "Transthyretin amyloidosis."

Medscape: "Transthyretin-Related Amyloidosis."

Sekijima, Y. Gene Reviews, Nov. 5, 2001.

Orphanet Journal of Rare Diseases: "Guideline of transthyretin-related hereditary amyloidosis for clinicians."

Boston University Amyloidosis Center: "Major Treatments."

American Liver Foundation: "Liver Transplant."

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