CYP2D6*145 is assigned uncertain function due to inadequate evidence. CYP2D6*145 is defined by the insertion of three amino acids which also define CYP2D6*30; *145 lacks two others also present in *30. In vitro studies demonstrated decreased enzyme activity for *30 compared to *1 with tamoxifen, bufuralol, dextromethorphan, and primaquine substrates (24647041, 30366777). Therefore, consensus among experts was uncertain function.