Definition of Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP)

Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP): a disabling and life-threatening genetic condition that leads to an abnormal accumulation of a protein known as amyloid in nerve cells. It is most common in people with Japanese, Swedish, or Portuguese ancestry. The condition arises from a mutation in a gene known as TTR and is inherited in an autosomal dominant pattern, meaning that only one copy of the defective gene is necessary to cause the condition. Symptoms typically develop in adulthood, from the 20s to the 70s. Symptoms are related to the abnormal accumulation of amyloid and can involve changes in sensation, difficulty with movement such as walking, decreased hearing, or vision loss. Amyloid also collects in the nerves that control important body functions like blood pressure, heart rate, and digestion. The most serious symptoms are an enlarged heart and irregular heartbeat (arrhythmia).

Also known as transthyretin-related hereditary amyloidosis, transthyretin amyloidosis, ATTR (hereditary form), Corino de Andrade's disease, Portuguese polyneuritic amyloidosis, Portuguese type familial amyloid neuropathy, Swiss type amyloid polyneuropathy, type I familial amyloid polyneuropathy, and type II familial amyloid polyneuropathy.