A complete diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM) includes genetic testing to identify the subtype. There are two subtypes of ATTR-CM: hereditary ATTR-CM (hATTR-CM) and wild-type ATTR-CM (wATTR-CM). Knowing which subtype you have means a better understanding of your symptoms, disease-specific treatment choices and potential disease progression. If you are diagnosed with hATTR-CM, your family members can also get testing to learn if they may be at risk for the disease.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
Diagnosing ATTR-CM
ATTR-CM is often underdiagnosed, due to a lack of awareness around the disease and the ease of mistaking its symptoms for other conditions. A correct diagnosis has historically taken several years, but recent advancements in diagnostic tests such as non-invasive nuclear cardiac imaging have changed this. A diagnosis of ATTR-CM is confirmed with the following tests:
- Electrocardiogram
- Echocardiogram
- Cardiac magnetic resonance imaging (CMR)
- Nuclear imaging (bone scan)
- Blood/urine tests
Once a diagnosis of ATTR-CM is confirmed, genetic testing and counseling is recommended to identify the subtype.
Differentiating between hereditary ATTR-CM vs wild-type ATTR-CM
A genetic test is non-invasive: all that is needed to screen for genetic mutations is a blood or saliva sample. If a mutation is identified, then a diagnosis of hereditary ATTR-CM is confirmed.
Hereditary ATTR-CM is caused by a mutation, fault or variation in the TTR gene. It is an inherited genetic mutation. There are 120 different mutations in the TTR gene, with each mutation causing different symptoms and prognosis.
Yet a wild-type ATTR-CM diagnosis is more likely: wild-type ATTR-CM is the more common subtype of ATTR-CM. It is associated with aging and is most often diagnosed in men over the age of 60. It is thought to be widely misdiagnosed due to its symptoms’ similarity with heart failure.
The benefits of genetic testing in ATTR-CM
Treatment for ATTR-CM is rapidly evolving. As new therapies emerge, the understanding of which treatments work best for specific subtypes and mutations is also growing. This means that knowing your specific subtype will allow for more tailored treatment.
It also means better care for family members. As hATTR-CM can be passed down through families, a hATTR-CM diagnosis can have implications for your loved ones. If a parent has hATTR-CM, there is a 50% chance that their child will have it too. However, even if your child has the gene mutation, this doesn’t necessarily mean they will develop hATTR-CM.
New therapeutic options for hATTR-CM have improved in recent years, but the best results stem from early intervention. If genetic testing confirms a loved one shares the gene mutation for hATTR-CM, their health will need to be carefully monitored so that if signs of hATTR-CM develop, the disease can be treated in its earliest stages.
No matter the results, the knowledge gained from genetic testing is an important step in finding disease-specific treatment that will help manage symptoms and slow disease progression.
Sign up here to get the latest news, perspectives, and information about ATTR-CM sent directly to your inbox. Registration is free and only takes a minute.
