Amyloidosis is a group of disorders that share a common pathobiology: in each case, a protein that exhibits misfolding is deposited in one or multiple organs leading to disruption in organ function. These amyloid proteins are recognized as amorphous pink material in Hematoxylin and Eosin staining, with confirmation by staining with Congo red and yellow or green birefringence under polarized light microscope. To date at least 36 different types of amyloid proteins have been identified. Worldwide, AA amyloidosis is the most common type, and this occurs secondary to chronic inflammatory disease states—such as chronic infections and rheumatological disorders. In western countries, the incidence of AA amyloidosis is decreasing, and AL is the most common type of amyloidosis, characterized by amyloid due to light chain deposition. ATTR amyloidosis, which can be either hereditary or acquired, is a unique variant of systemic amyloidosis that results from mutations in the transthyretin (TTR) gene. Our review will focus on clinical features of the most common systemic amyloidosis, with a detailed review on evaluation and management of AA, AL and ATTR amyloidosis.
Part of the book: Amyloid Diseases