CYP2B6*7 (c.516G>T, p.Q172H/splice defect; c.785A>G, p.K262R and c.1459C>T, p.R487C) - Decreased function: CYB2B6*7 is assigned decreased function. CYP2B6*7 contains the variants which define CYP2B6*6 in addition to a third SNP (c.1459C>T). Since this is a rare variant, there are no data from human liver microsomes or clinical trials regarding its function. Data from several in vitro expression systems are inconclusive: some studies show decreased activity (31324697, 32238417, 3553863) while others exhibit increased activity (12642465, 21659470, 30201214). This discrepancy is probably due to differences in the in vitro expression systems and substrates used. As is the same for *6, the mechanism for decreased activity is aberrant splicing caused by c.516G>T, which leads to reduced amounts of protein and thus, activity (14551287, 18171905, 24260284). As a result, alleles having c.516G>T are considered decreased function, regardless of the functional status of additional other variants unless these cause no function (e.g., CYP2B6*13 and CYP2B6*38). Therefore, the consensus among experts was decreased function based on the presence of c.516G>T and limited evidence.