CYP2B6*14 (c.419G>A, p.R140Q) - Uncertain function: CYP2B6*14 is assigned uncertain function. In vitro studies using human liver microsomes (17559344, 15190123) and cDNA expression systems (15190123, 20517174, 30201214, 21746968) found that CYP2B6*14 has decreased enzyme activity compared to the *1 reference. However, due to the lack of any in vivo or clinical evidence, consensus among experts was uncertain clinical function based on limited evidence.