Hereditary transthyretin amyloidosis (hATTR amyloidosis) is a rare genetic disorder that causes a buildup of abnormal proteins called transthyretin (TTR) proteins.
TTR proteins are "transport proteins"—proteins that help move hormones and vitamins into cells. Most TTR proteins are made in the liver, while small amounts are produced in the brain.
When a person has hATTR amyloidosis, genetic mutations cause the body to produce misfolded TTR proteins. Misfolded TTR proteins are misshapen and do not function correctly. As more misfolded TTR proteins accumulate, they form deposits that can damage the organs and tissues where they are located. This is called amyloidosis.
People with hATTR amyloidosis experience nerve damage, stiffening and thickening of the heart muscle, gastrointestinal problems, kidney disease, and other complications. Symptoms and complications become more severe over time, especially when the disorder is untreated.
For many years, liver transplants were considered the best treatment option—because most TTR was made in the liver, receiving a transplanted liver would reduce the production of the misfolding TTR and help prevent further damage to the body. Liver transplants are most successful when performed in young patients in the early stages of the disease. Liver transplants also appear to be more effective for cases caused by specific gene mutations. Heart transplants are also used in cases where the disease has damaged the heart.
Over the past decade, new treatments have become available and liver transplants have become less common. While there are no therapies that can cure hATTR amyloidosis, there are therapies that can help people manage this condition and slow the progression of the disease.
Treatment options for hATTR amyloidosis
Treatments for hATTR amyloidosis fall into two main categories— therapies that prevent the TTR protein from misfolding and therapies that reduce the production of TTR protein. Keep in mind that these are simplified explanations of complex mechanisms:
TTR stabilizers
TTR stabilizers are medications that attach to TTR proteins, stabilize the proteins, and prevent misfolding. This prevents the formation of amyloid deposits and helps slow the progression of the disease. Some medications are approved for the treatment of hATTR amyloidosis, and others are prescribed off-label. Off-label means that a drug has been approved for other conditions, but it has been shown to benefit people with a different condition.
Gene-silencing therapies
The body has a built-in defense mechanism that helps clear up gene mutations and regulate protein production. It is called RNA interference. Gene-silencing therapies are drugs that mimic this process. Gene-silencing therapies for hATTR work by interfering with the production of misfolding TRR proteins.
Research into hATTR is ongoing, and new therapies are under development.
Managing symptoms and complications
Managing symptoms and complications are also an important part of treatment for hATTR. It can include medications to manage nerve pain and discomfort, medications and therapies to treat cardiac complications like heart failure, and therapies to help with gastrointestinal symptoms. Good nutrition and overall health should also be a focus of treatment.
Hereditary ATTR is a different experience for different people. Treatment for hATTR should be individualized to a person's specific symptoms and needs. Your best source of information about treatment options for hATTR will be your healthcare providers.
