Understanding Amyloidosis: Etiology, Epidemiology, Pathophysiology, Management

Amyloidosis is a heterogeneous disease that results from the deposition of toxic insoluble beta-sheet fibrillar protein aggregates in different tissues. Amyloidosis can be acquired or hereditary. The disease can be localized or systemic. Amyloid can accumulate in liver, spleen, kidney, heart, nerves, and blood vessels causing different clinical syndromes including cardiomyopathy, hepatomegaly, proteinuria, macroglossia, autonomic dysfunction, ecchymoses, neuropathy, renal failure, hypertension, and corneal and vitreous abnormalities.

The most common causes of amyloidosis are the immunoglobulin-light-chain relate amyloidosis (AL), ATTR amyloidosis, and reactive amyloidosis (AA) due to chronic inflammatory diseases like chronic infections and rheumatoid arthritis. AL amyloidosis is acquired and is caused by a small plasma cell clone that produces misfolded amyloidogenic light chains that deposit in different organs and tissues.

AL amyloidosis has an incidence of 1 case per 100,000 person-years in Western countries. In the United States, there are approximately 1275 to 3200 new cases per year. The annual proportion of new cases with AL is 78%. Familial transthyretin-associated amyloidosis (ATTR) is a less common systemic type of amyloidosis with unknown incidence, but approximately 10% to 20% of diagnosed cases in tertiary centers are secondary to ATTR amyloidosis.