ATTR Amyloidosis is caused by the accumulation of a genetically variant form or even the normal form of the protein, transthyretin, into amyloid fibrils. Transthyretin is produced in everyone and is primarily made within the liver. It appears that in every one this particular protein will eventually form amyloid fibrils that can cause organ dysfunction primarily in the heart and nerves. Fortunately, this process is slow in most of us and does not lead to problems in a normal life span. Unfortunately, for some individuals this process occurs more quickly and can lead to symptoms of heart failure and nerve damage, (neuropathy), earlier in life. Most typically, these afflicted individuals have a genetic variant of the transthyretin protein which they were born with passed down from their mother or father. This occurs more commonly in certain regions of the world; Portugal, Sweeden and Japan being leading examples. Other areas such as the Appalachian mountain region here in the United States have a higher incidence of affected people because of a common genetic variant in the population there. We happen to be seeing more and more patients presenting to the Heart Transplant Program with symptoms of heart failure who are not found to have a variant transthyretin gene. These patients have been diagnosed with wild-type, (senile), ATTR. It is not yet clear why these latter individuals develop the process within their heart earlier than average despite a normal protein gene sequence.
Treatment of each of these conditions focuses upon medication to make the affected organs function better, or transplantation of the organ such as the heart, in the event of heart failure. In patients with the variant forms of transthyretin, a liver transplant is often performed as well to reduce the production of that protein so the new heart or affected nerves do not get further harmed.
In the case of amyloid heart disease, heart transplantation may also be done. We have one of the leading heart transplant centers within the United States and have performed heart transplants for patients with ATTR and AL amyloidosis numerous times. Unfortunately, amyloidosis involving the heart can be quite serious leading to intractable heart failure or even death from an arrhythmia. It is important to be seen by a team of physicians particularly familiar with the issues related to patients with cardiac amyloidosis. In some cases of inherited amyloidosis, liver transplantation can help because it removes the source that produces the mutant protein. We have performed combined heart/liver transplants for patients with ATTR amyloidosis with good success.