Human CYP2D6*35X2 allele is located in the vicinity of 22q13.1 and is approximately 4 kb in length. This allele, an amplification variant form of the CYP2D6 wild-type allele, encodes cytochrome P450 2D6*35 protein. The CYP2D6*35 allele exhibits four SNPs (g.31G>A; g.1661G>C; g.2850C>T; g.4180G>C) that result in three coding changes (V11M; R296C; S486T). The CYP2D6*35X2 allele has two copies of the CYP2D6*35 allelic variant. This duplication increases the enzymatic activity of the cytochrome P450 2D6*35 protein in subjects who carry this allele. [ ]