MIF abundance is regulated by a genetic polymorphism
MIF protein is regulated by a promoter microsatellite region with large variance in the human population. This region may have between 5 and 8 CATT repeats. People with the 5-CATT repeat allele express substantially lower amounts of endogenous MIF, and have been shown to suffer worse outcomes following cardiac surgery.
Prevalence of 5-CATT (low MIF expression) allele around the world.
>5-CATT: Normal MIF Expression
5-CATT: Low MIF Expression