CYP2D6*106 is assigned uncertain function due to inadequate evidence. CYP2D6*106 is defined by a single SNP which in silico studies predict to be a benign amino acid change (26937359). An in vitro study found CYP2D6*106 demonstrated decreased enzyme activity compared to wildtype with bufuralol and dextromethorphan substrates (23897164). Consensus was not achieved among experts as data were sparse. Therefore, uncertain function was assigned.