Hereditary transthyretin amyloidosis is a rare disease that creates abnormal transthyretin (TTR) proteins. These misfolded proteins form clumps known as amyloid fibrils, which can affect your nervous system, heart, eyes, and gastrointestinal tract in ways that get worse over time. Studies dating from 2012 and 2015 showed that the median overall survival rate of hATTR amyloidosis was 4.7 years. This means that 4.7 years after diagnosis, half of the study participants were still alive.
Fortunately, new treatments are extending the life span of those living with hATTR amyloidosis. These therapies help stabilize TTR proteins or stop your liver from making them, which prevents fibrils from collecting in your organs and causing dysfunction. Read on to learn how the life expectancy of those with hATTR amyloidosis has improved in recent years.
Hereditary transthyretin amyloidosis is an inherited condition passed down through family members. Doctors and researchers have discovered more than 120 TTR gene mutations around the world that contribute to this disease. Two of the most common mutations are known as V30M and V122I.
Studies show that the type of gene mutation is associated with some symptoms more than others as amyloid deposits form in the organs and tissues. For example, people with the V30M mutation tend to have more widespread symptoms caused by neuropathy (nerve damage). On the other hand, nearly all people with the V122I mutation eventually develop cardiomyopathy, a condition that reduces the heart’s ability to pump blood.
In addition, hATTR amyloidosis is a progressive disease — symptoms continue to worsen over time with amyloid buildup. Researchers have found that those with V122I mutations and heart involvement live, on average, 3.4 years after diagnosis. Amyloid fibrils affect the heart, interfering with its ability to pump blood and maintain rhythm. Many people with cardiomyopathy eventually develop progressive heart failure or have arrhythmias (abnormal heart rhythms), which are life-threatening if left untreated.
The gold standard for treating hATTR amyloidosis since 1990 has been liver transplantation. The liver is responsible for producing most of your body’s TTR protein. The transplanted liver doesn’t make abnormal proteins, so disease progression slows over time or even stops. In the past 25 years, liver transplants have significantly improved survival in those with hATTR amyloidosis.
Although liver transplants are a highly effective treatment, there aren’t enough donors available to meet the needs of those with other liver diseases. Fortunately, the U.S. Food and Drug Administration (FDA) has approved new therapies in recent years, improving the quality of life for people living with hATTR amyloidosis.
The four FDA-approved therapies currently available are:
These treatments were approved in just the past several years, so data on their long-term effects on survival is limited. As more people with hATTR amyloidosis begin treatment and stay on it longer, more studies can be performed to determine whether these drugs improve life expectancy.
Read more about hATTR amyloidosis treatments.
One large study of more than 3,000 people with hATTR amyloidosis with V30M mutations studied how liver transplants and treatment with tafamidis affected survival rates. The study authors found that after 10 years, nearly 93 percent of people treated with tafamidis were alive, compared with 85 percent of those who underwent liver transplantation. These results show that tafamidis treatment helps more people live longer than a liver transplant.
According to a study in the journal Neurology, tafamidis treatment also improved survival in those diagnosed before age 50 (known as early-onset disease), reducing the risk of death by 91 percent. People who are diagnosed with hATTR amyloidosis at age 50 and older and who don’t receive treatment tend to have a poorer prognosis. Tafamidis reduced the risk of death by 82 percent in this group, compared with those who were not treated.
Factors besides medications can also influence your prognosis while living with hATTR amyloidosis. Studies show that age and diet may affect your outlook and overall health.
The time of diagnosis affects the average life expectancy of those who have hATTR amyloidosis with polyneuropathy. People who are diagnosed with early-onset disease with V30M mutations and polyneuropathy symptoms have lived for about 12 years after diagnosis. By contrast, those with late-onset disease have lived for around seven years after diagnosis.
Although no research points to the benefits of specific diet changes in hATTR amyloidosis, the American Heart Association recommends a heart-healthy diet low in sodium for anyone living with cardiomyopathy or heart disease. Diets high in sodium or salt contribute to increased blood pressure, putting extra strain on your heart. Watching what you eat can help reduce your risk of other health complications, which may extend your life span.
As doctors and researchers continue to learn more about hATTR amyloidosis, they’re developing new treatments to help control symptoms, improve quality of life, and extend life span. Clinical trials are studying new treatments, and researchers are learning more about therapies that are already approved. As more long-term studies continue, researchers will learn more about the treatments’ effects on survival.
You can take an active role to stay your healthiest and live longer with hATTR amyloidosis. Be sure to stay in touch with your health care team about any new symptoms you’re experiencing, along with any side effects from your medications. Your doctor is your partner in treating this long-term condition and improving your prognosis (outlook).
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