SAA1

Several studies of people with familial Mediterranean fever indicate that having the alpha version of the serum amyloid A1 protein increases the risk of a serious complication called amyloidosis. Amyloidosis involves the buildup of protein deposits that can lead to kidney failure if left untreated. Studies indicate that individuals with familial Mediterranean fever who also have the alpha version of the protein are two to seven times more likely to develop amyloidosis than are people with the beta or gamma version.

More serum amyloid A1 is produced in the body during episodes of inflammation such as those that occur in familial Mediterranean fever. This protein and related compounds may form abnormal clumps in the body's organs and tissues. It remains unclear, however, how the alpha version of serum amyloid A1 increases the susceptibility to amyloidosis (or alternatively, how the beta and gamma versions may protect against this complication) in people with this disorder.

Among people with certain other inflammatory disorders, studies indicate that variants of the serum amyloid A1 protein also modify the risk of amyloidosis. For example, in the Japanese population, the gamma version of the protein appears to increase the risk of amyloidosis among adults with rheumatoid arthritis. Among white people with juvenile chronic arthritis, the alpha version indicates a high risk of developing amyloidosis.

More serum amyloid A1 is produced in the body during chronic inflammation such as occurs in these disorders. This protein and related compounds may form abnormal clumps in the body's organs and tissues. It remains unclear, however, how certain versions of serum amyloid A1 increase the susceptibility to amyloidosis.