Interacting Gene/EnzymeAllele nameGenotype(s)Defining Change(s)Type(s)DescriptionDetailsCytochrome P450 2D6CYP2D6*4(A;A)A Allele, homozygoteEffect Directly StudiedPatients with this genotype have reduced metabolism of tamoxifen resulting in reduced plasma concentrations its active form endoxifen.DetailsCoagulation factor V---(A;A) / (A;G)A alleleADR Directly StudiedPatients with this genotype have increased risk of a thromboembolic event with tamoxifen.DetailsCytochrome P450 2D6CYP2D6*3Not AvailableC alleleEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*5Not AvailableWhole-gene deletionEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*6Not Available1707delTEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*7Not Available2935A>CEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*8Not Available1758G>TEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*11Not Available883G>CEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*12Not Available124G>AEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*13Not AvailableCYP2D7/2D6 hybrid gene structureEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*14ANot Available1758G>AEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*15Not Available137insT, 137_138insTEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*19Not Available2539_2542delAACTEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*20Not Available1973_1974insGEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*21Not Available2573insCEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*31Not Available-1770G>A / -1584C>G  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*36Not Available100C>T / -1426C>T  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*38Not Available2587_2590delGACTEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*40Not Available1863_1864ins(TTT CGC CCC)2Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*42Not Available3259_3260insGTEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*44Not Available2950G>CEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*47Not Available100C>T / -1426C>T  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*51Not Available-1584C>G / -1235A>G  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*56Not Available3201C>TEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*57Not Available100C>T / 310G>T  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*62Not Available4044C>TEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*68ANot Available-1426C>T / -1235A>G  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*68BNot AvailableSimilar but not identical switch region compared to CYP2D6*68A. Found in tandem arrangement with CYP2D6*4.Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*69Not Available2988G>A / -1426C>T  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*92Not Available1995delCEffect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*100Not Available-1426C>T / -1235A>G  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetailsCytochrome P450 2D6CYP2D6*101Not Available-1426C>T / -1235A>G  … show all Effect InferredPoor response to drug treatment, shorter time to relapseDetails