Key Information
Transthyretin amyloid cardiomyopathy (ATTR-CM) is a rare, progressive condition that occurs when a protein called transthyretin builds up abnormally in the heart. Normally, transthyretin helps carry thyroid hormone and vitamin A through the body. However, when it becomes unstable due to gene changes (mutations) or ageing, it can break down and form deposits, mainly in the heart.
Over time, these deposits cause the heart muscle to become thick and stiff. This makes it harder for the heart to pump blood effectively and can lead to heart failure. Symptoms of ATTR-CM usually develop gradually and may include shortness of breath, fatigue, swelling in the legs or abdomen, and an irregular heartbeat. In some people, transthyretin deposits can also build up in other parts of the body, including the nerves which may cause symptoms such as pain or numbness in the hands, lower back or legs.