**3.2 Amyloid-associated type (AA) protein**

AA type amyloidosis is the most common amyloid worldwide. AA type amyloid is an acute phase protein derived from SAP by proteolysis. AA type amyloid is made in the liver, bounds to high-density lipoprotein (HDL), and is associated with chronic inflammatory disorder. In the past, the primary cause was predominantly of infections such as tuberculosis and chronic osteomyelitis. Nowadays, with the development of antibiotics, the most common source of AA type amyloid has become noninfectious inflammatory conditions, such as rheumatoid arthritis or inflammatory bowel diseases including Crohn's disease and ulcerative colitis. Typical organs of AA type amyloid deposition are the kidney, liver, and spleen. AA type amyloidosis is also related to hereditary amyloidosis, caused by familial Mediterranean fever inherited as an autosomal recessive pattern. This is an autoinflammatory disorder characterized by frequent fever and serosal inflammation. The main affected organ is the kidney, but other organs such as the heart, spleen, and gastrointestinal tract can be affected [4].
