Familial amyloid polyneuropathy (FAP) is a progressive neurodegenerative condition caused by a mutation in the transthyretin (TTR) gene. It is characterized by the buildup of abnormal TTR protein deposits (amyloids) in various parts of the body especially in the kidneys, peripheral nervous system, and heart. The buildup of amyloids, or amyloidosis, results in stiffness of the organs, thereby affecting their function and leading to the symptoms of FAP.

Cardiac involvement has been reported in about five to 23 percent of FAP cases. Older patients with FAP are at higher risk of developing cardiac complications, and 80 percent of FAP patients with cardiac involvement are men.

If left untreated, cardiac complications can cause heart failure within five to 15 years. Cardiac symptoms are usually preceded by peripheral neuropathy symptoms such as carpal tunnel syndrome (numbness, tingling, and pain in the arm and hands).

FAP-associated cardiac amyloidosis

The stiffening and thickening of heart muscles due to amyloidosis can cause cardiomyopathy or heart muscle disease, and hinder the heart’s ability to pump blood properly.

Most often, the first symptom of cardiac amyloidosis is arrhythmia or an irregular heartbeat. It may be present in patients for years before diagnosis.

Insufficient blood being pumped by the heart may cause shortness of breath, or dyspnea, which may be more evident upon physical exertion. Patients may tire quickly and experience weakness, fatigue, and fainting.

Some FAP patients may exhibit swelling in the legs due to water retention, a symptom of reduced heart function, which can lead to reduced blood flow that can cause angina or chest pain.

Diagnosis of cardiac involvement

Once cardiac involvement is suspected, imaging tests are used to visualize amyloid deposits, and determine heart health and function. Non-invasive exams include:

In some instances, a myocardial biopsy may be recommended to confirm the diagnosis. This is an invasive procedure and, therefore, not frequently used.

Treatment of cardiac symptoms

Most therapeutic options currently available for FAP-associated cardiac amyloidosis are supportive in nature. For example, an irregular heart rhythm can be restored with cardioversion therapy or managed with antiarrhythmic medications. Pacemakers can help the heart beat so it can pump blood efficiently. In serious cases, doctors may recommend a heart transplantation in patients who have not responded to any other supportive treatments.

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FAP News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Vijaya Iyer is a freelance science writer for BioNews Services. She has contributed content to their several disease-specific websites, including cystic fibrosis, multiple sclerosis, muscular dystrophy, among others. She holds a PhD in Microbiology from Kansas State University, where her research focused on molecular biology, bacterial interactions, metabolism, and animal models to study bacterial infections. Following the completion of her PhD, Dr. Iyer went on to complete three postdoctoral fellowships at Kansas State University, University of Miami and Temple University. She joined BioNews Services to utilize her scientific background and writing skills to help patients and caregivers remain abreast with important scientific breakthroughs.
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Vijaya Iyer is a freelance science writer for BioNews Services. She has contributed content to their several disease-specific websites, including cystic fibrosis, multiple sclerosis, muscular dystrophy, among others. She holds a PhD in Microbiology from Kansas State University, where her research focused on molecular biology, bacterial interactions, metabolism, and animal models to study bacterial infections. Following the completion of her PhD, Dr. Iyer went on to complete three postdoctoral fellowships at Kansas State University, University of Miami and Temple University. She joined BioNews Services to utilize her scientific background and writing skills to help patients and caregivers remain abreast with important scientific breakthroughs.
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