CYP2D6*109 is assigned decreased function based on limited evidence. *109 has the 2616delAAG (also present in *9 with decreased function-PMID 1844820; 8101460; 11266079; 24647041; 30366777) and 3184G>A (V338M) which is a core SNP of *29. One study compared activity of V338M vs that of V136I (both present in *29) and found that both decrease activity in vitro (PMID 11470994). Because both variants have been shown to have decreased function in vitro, consensus of the experts was decreased function with limited evidence.