Meta-Biol

• Pathways

CYP2D6 (debrisoquine 4-hydroxylase) has a wide substrate specificity and is an important cytochrme P450 in drug metabolism. It has extensive genetic polymorphism (called the debrisoquine/sparteine oxidation polymorphism) that influences its expression and function.The polymorphism is responsible for populations being poor metabolizers (PM) or extensive metabolizers (EM, normal). Approximately 10% of Caucasians and less than 1% of Asians lack the CYP2D6 protein because of two null alleles which do not encode the functional product. Further polymorphisms discovered recently have identified ultrarapid metabolizers (PM) (alleles with multiple gene copies) and intermediate metabolizers (IM) (deficiency in their metabolism capacity) (Zanger UM et al, 2004).