Overview
CYP2D6 is a member of the cytochrome P450 enzyme family. It is primarily active in the liver and is responsible for the breakdown of approximately 20-25% of clinically used drugs. Due to strong genetic variations, individuals metabolize drugs extremely differently â from almost not at all (Poor Metabolizer) to extremely fast (Ultrarapid Metabolizer).
22q13.2 (Chromosome 22)
Metabolism
Autosomal codominant
7-10% (Europeans)
Function & Significance
The CYP2D6 enzyme processes substances such as antidepressants (e.g., SSRIs), beta-blockers, antiarrhythmics, and painkillers (e.g., codeine, tramadol). For codeine, CYP2D6 is responsible for converting the drug into active morphine.
âšī¸ Personalized Medicine
Knowledge of CYP2D6 status allows physicians to tailor drug dosages individually. “Poor Metabolizers” risk severe side effects at standard doses, while “Ultrarapid Metabolizers” often feel no effect because the body eliminates the active ingredient too quickly (or, in the case of codeine, converts it too quickly into toxic amounts of morphine).
đ§Ŧ Relevant SNP
One of the most common function-reducing variants (CYP2D6*4):
22:42128945
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CYP2D6*4 (G>A):
This is a splice-site mutation (G>A) resulting in an inactive enzyme. Individuals with the AA genotype are “Poor Metabolizers.”
đ Data Sources
- OMIM: #124030 – Cytochrome P450, Subfamily IID, Polypeptide 6; CYP2D6
- PharmGKB: Gene-Specific Information for CYP2D6
- CPIC: Clinical Pharmacogenetics Implementation Consortium Guidelines
Biological Function
Associated Conditions
Analyzed Markers
CYP2D6*4 - Most common variant leading to complete loss of enzyme function (Poor Metabolizer).