Systemic Amyloidosis

These are pathologies characterized by abnormalities in the formation of proteins that cause a change in their structure, causing the deposition of insoluble amyloid fibrils in the extracellular spaces of organs and tissues. Depending on the characteristics of the proteins, the deposition can be localized or affect almost any organ. The classification is very difficult as these forms can be of neoplastic, inflammatory, genetic, or iatrogenic origin. The most common form is AL (so-called primitive) amyloidosis, characterized by the deposition of fragments of monoclonal immunoglobulin light chains: it can occur on its own or during multiple myeloma. Another relatively common form is the so-called inflammatory amyloidosis AA, which occurs as a result of the accumulation of amyloid A proteins in chronic inflammatory diseases (osteomyelitis, tuberculosis, leprosy, Mediterranean familial fever, connective tissue diseases, etc.). Finally, hereditary forms that can determine the deposition of molecules derived from various proteins (transthyretin, apolipoproteins, cystatin c, gelsolin, fibrinogen alpha chain, and many others) are less common.