The patient with amyloidosis

Amyloidosis is a disorder of protein folding in which normally soluble plasma proteins are deposited in the extracellular space in an abnormal insoluble fibrillar form. The process of amyloid formation and deposition causes cytotoxicity and progressive organ dysfunction. Amyloid is remarkably diverse and can be hereditary or acquired, localized or systemic, and lethal or merely an incidental finding. The most important numerically are AL amyloidosis, in which the fibrils are composed of monoclonal immunoglobulin light chains, and AA amyloidosis, in which the acute phase reactant Serum Amyloid A component forms the fibrils. The kidney is involved in 75% of patients with systemic amyloidosis. Heavy proteinuria or nephrotic syndrome is characteristic of most amyloid variants. Without treatment, systemic disease is usually fatal but measures that reduce the supply of amyloid fibril precursor proteins can result in regression of amyloid deposits, prevention of organ failure, and improved quality of life and survival. Early diagnosis, before irreversible organ damage has occurred, is the key to effective treatment. Recent advances in diagnosis and therapy have much improved the outlook of patients with AL amyloidosis, but agents with broader promise are under investigation.