CYP2D6*27x2 was deposited into PharmVar. CYP2D6*27 is assigned normal function based on limited evidence. Multiple in vitro studies found CYP2D6*27 demonstrated similar activity compared to wildtype with various substrates (18784265, 18838503). Although some in vitro studies found CYP2D6*27 demonstrated modestly decreased activity it was not convincing the magnitude of decreased activity was clinically significant (24647041, 30366777). Therefore, consensus among experts was normal function with an activity value of 1 based on limited evidence as it was determined the phenotypes containing this allele would be clinically similar to phenotypes comprising normal function alleles. Based on other normal function alleles such as *1, *2, *45, a duplication of a normal function allele is assigned an activity value of 2 and increased function.