SAA1 gene
The SAA1 gene produces the serum amyloid A1 protein, which plays a role in the immune system's inflammatory response and is linked to the risk of amyloidosis in certain conditions.
Normal Function
The SAA1 gene provides instructions for making the protein serum amyloid A1. Primarily produced in the liver, this protein circulates in the blood at low levels. While its exact function is not fully understood, it appears to be involved in the immune system by helping to repair damaged tissues, acting as an antibacterial agent, and signaling the migration of white blood cells to sites of infection.
During inflammation—the body's response to injury or disease—levels of serum amyloid A1 increase significantly. Once the immune system has addressed the threat and facilitated repair, the inflammatory response ceases to prevent damage to healthy cells.
There are three versions of this protein: alpha, beta, and gamma. The prevalence of these versions varies by population; for example, the alpha version is predominant in white populations, while all three versions appear with nearly equal frequency in the Japanese population.
Health Conditions Related to Genetic Changes
Familial Mediterranean fever
In individuals with familial Mediterranean fever, the presence of the alpha version of the serum amyloid A1 protein is associated with an increased risk of amyloidosis. This serious complication involves the buildup of protein deposits that can lead to kidney failure if left untreated.
- Individuals with familial Mediterranean fever who carry the alpha version are two to seven times more likely to develop amyloidosis compared to those with the beta or gamma versions.
- During inflammatory episodes, the body produces excess serum amyloid A1, which may form abnormal clumps in tissues and organs.
- It remains unclear why the alpha version increases susceptibility to amyloidosis or how the beta and gamma versions might offer protection.