CYP2C19*2 is assigned no function based on definitive evidence. CYP2C19*2 has been studied for more than 20 years and its association with impaired function is well-established (8195181, 22027650). CYP2C19*2 is defined by splicing defects resulting in a truncated protein lacking a heme binding region, making it a nonfunctional protein. CYP2C19*2 was first identified in a homozygous subject demonstrating decreased mephenytoin metabolism and was subsequently identified in seventeen additional subjects demonstrating decreased mephenytoin metabolism (8195181). Therefore, consensus among experts was no function based on definitive evidence.