CYP2B6*3 (c.777C>A, p.S259R) - Uncertain function: CYP2B6*3 is assigned uncertain function. In vitro studies using cDNA expression systems demonstrated that CYP2B6*3 had similar enzyme activity or slightly decreased activity compared to the *1 reference (12642465, 30201214). This discrepancy is probably due to differences in the in vitro expression systems and substrates used. Therefore, consensus among experts was uncertain function due to inadequate evidence.