CYP2C19*7 is assigned no function based on limited evidence in a heterozygous subject. CYP2C19*7 is defined by a splicing defect and was described in a subject demonstrating decreased metabolism of mephenytoin based on urine metabolite concentrations after three separate phenotyping studies (10411572). Therefore, consensus among experts was no function based on limited evidence as it was determined the phenotypes containing this allele would be clinically distinct from phenotypes comprising normal function and decreased function alleles.