CYP2D6*11 is assigned no function based on limited evidence. CYP2D6*11 is defined by a splicing defect yielding a nonfunctional enzyme and was identified in a subject demonstrating markedly decreased sparteine metabolism (8563771, 9241659). Therefore, consensus among experts was no function with an activity value of 0 based on limited evidence as it was determined the phenotypes containing this allele would be clinically distinct from phenotypes comprising normal and decreased function alleles.