Cytochrome P450 family 2 subfamily D member 6 (CYP2D6) (CYP2D6)

Cytochrome P450 family 2 subfamily D member 6 (CYP2D6) is a critical microsomal enzyme primarily localized in the liver and kidneys [1, 3, 6]. It is responsible for the oxidative metabolism of approximately 25% of all clinically used drugs, including antidepressants, antipsychotics, beta-blockers, and opioids [3, 15]. In clinical diagnostics, CYP2D6 is identified as the primary autoantigen targeted by liver-kidney microsomal type 1 (LKM-1) autoantibodies, which serve as the definitive serological marker for Autoimmune Hepatitis Type 2 (AIH-2) [1, 2, 6]. The CYP2D6 gene is exceptionally polymorphic, leading to distinct metabolic phenotypes—poor, intermediate, extensive, and ultrarapid metabolizers—that dictate the pharmacological efficacy and toxicity of numerous medications [3, 15]. While the name 'Liver and Kidney' provided is anatomically descriptive and refers to the organ-based detection of the LKM-1 antigen, it is technically an incorrect designation for the molecular target itself in a pharmacological context [3, 6].

Other names

Liver kidney microsome type 1 antigenLKM-1 antigenCytochrome P450 2D6Debrisoquine 4-hydroxylaseCPD6CYPIID6

Oxidative metabolism of xenobiotics; bioactivation of prodrugs (e.g., codeine conversion to morphine); competitive and non-competitive inhibition by pharmacological agents.