COMT Genotyping

Catechol-O-Methyltransferase (COMT) is an enzyme that inactivates hormones, such as epinephrine, norepinephrine, and dopamine. The hormones help to regulate heartbeat, breathing rate, cognitive function, memory, mood, and pain perception.

A variety of drugs, such as nicotine replacement therapy (NRT), entacapone (Comtan®), opioids, SSRIs, and antipsychotics, may be directly or indirectly impacted by the change in catecholamines inactivation.

The activity of this enzyme increases linearly with age — regardless of genotype. COMT comes in two forms: soluble and membrane. The soluble form is most often found in the liver, kidneys, and gastrointestinal tract, while the membrane-bound form is most common in the brain. COMT genetic variant tested is c.472G>A.

Indications for COMT Testing

Patients taking medications used in the treatment of Parkinson’s disease, specifically entacapone, are good candidates for COMT testing.[45] Providers looking for patients that may be more responsive to NRT may also consider COMT testing. COMT genetic variations may also affect patients taking opioids, antidepressants, and antipsychotics — however — the evidence is conflicting. In general, assessment of medical necessity for testing is up to the provider’s clinical judgment.