ABOUT AMYLOIDOSIS

In hereditary ATTR amyloidosis, a changed (abnormal) version of the protein is inherited from one or both parents. This changed protein does not have the usual shape, so it easily forms amyloid deposits in the heart and nerves. Depending on the specific way its shape is changed, it can cause problems mostly in the heart, nerves, or both.

In wild-type ATTR amyloidosis, the TTR protein gradually deposits in the heart over many years, and we don’t fully understand why this happens. This type of amyloidosis most often affects older men, but can also affect women.

Amyloid protein builds up in the heart, sticking between the heart muscle cells like glue. This makes the heart thicker and less flexible. Normally, when the heart beats, it relaxes to let blood flow in and then squeezes to pump blood to the rest of the body. But when the heart is stiff, it has trouble relaxing properly, which makes it harder for blood to fill. As a result, blood backs up into the lungs (causing shortness of breath), abdomen (leading to bloating, poor appetite, and nausea), and legs (causing swelling). Since the heart does not fill completely, there is less blood available to push forward when it contracts. This means less blood reaches the muscles (causing tiredness, shortness of breath), brain (resulting in dizziness, fainting, and tiredness), and internal organs (which may lead to kidney and other organ problems). Amyloid can also weaken the heart muscle, further reducing its ability to pump blood effectively. Lastly, amyloidosis increases the chances of having abnormal heart rhythms, such as atrial fibrillation.

Outside the heart, certain types of amyloidosis can affect the nerves that control heart rate and blood pressure. This can result in low blood pressure, especially when going from sitting or lying down to standing up. This may make some patients more likely to feeling dizzy or fainting.