The protein belongs to a family of enzymes called caspases which cleave their substrates at C-terminal aspartic acid residues.

The CASP12 gene is subject to polymorphism, which can generate a full-length caspase protein (Csp12L) or an inactive truncated form (Csp12S).

The functional form appears to be confined to people of African descent and is linked with susceptibility to sepsis; people carrying the functional gene have decreased responses to bacterial molecules such as lipopolysaccharide (LPS).

[7][8] A study in May 2009 by McGill University Health Centre has suggested that estrogen may serve to block the production of caspase-12, resulting in a stronger inflammatory reaction to bacterial pathogens.

[9][10][11] The inactive truncated form (Csp12S) of the CASP12 gene was spread and nearly fixed in non-African populations due to positive selection beginning perhaps 60–100 thousand years ago.