A Physician's Guide to AL (Light Chain) Amyloidosis

Amyloidosis is a disorder in which misfolded native proteins deposit extracellularly and lead to organ damage. Although the various types of amyloidoses share in common the deposition of misfolded proteins that aggregate as fibrils in tissue, they differ in actual protein composition, organ involvement, prognostic implication and most importantly, treatment. It is therefore critically important to determine the type of amyloidosis a patient has in order to provide the appropriate treatment.

There are at least 23 different proteins associated with amyloidosis. The most common type of amyloidosis and the one that is associated with a poor prognosis if left untreated is called AL amyloidosis and due to the deposition of clonal immunoglobulin light chains produced by plasma cells in the bone marrow.

There are several types of hereditary amyloidoses, most common of which is mATTR amyloidosis, an autosomal dominant disease that results from misfolding of mutant transthyretin, a protein produced in the liver containing a single point gene mutation. More than 100 different transthyretin mutations are known to cause amyloidosis.