CYP2B6*12 (c.296G>A, p.G99E) - No function: CYB2B6*12 is assigned no function. Multiple in vitro studies using human liver microsomes (15190123) and cDNA expression systems (20517174, 21746968, 30201214) found that CYP2B6*12 has no protein expression or enzyme activity compared to the *1 reference with various substrates. Therefore, consensus among experts was no function based on limited evidence.