CYP2B6*8 (c.415A>G, p.K139E) - No function: CYP2B6*8 is assigned no function. Multiple in vitro studies using human liver microsomes (14551287) and cDNA expression systems (15190123, 20517174, 21659470, 21746968, 30201214) found that CYP2B6*8 had no enzyme activity compared to the *1 reference with various substrates. Therefore, consensus among experts was no function based on limited evidence.