Your Migraines Are Triggered by Your Genes, Not Just Stress.

MTHFR is an enzyme that converts folate into methylfolate, the active form your cells use for hundreds of critical processes, including the production of nitric oxide. Nitric oxide is the molecule that tells your blood vessels when to relax and dilate. When this pathway is working normally, your cerebral blood vessels respond smoothly to changes in oxygen demand and blood pressure.

The MTHFR C677T variant, carried by approximately 40% of people with European ancestry, reduces this enzyme’s efficiency by 40 to 70 percent. You can eat plenty of folate and still be functionally depleted at the cellular level. Your cells can’t convert it fast enough. This leads to two problems: impaired methylation (which affects neurotransmitter production, DNA repair, and immune function) and reduced nitric oxide availability (which means your blood vessels lose their ability to respond smoothly to triggers).

When your blood vessels can’t regulate tone properly, they become reactive. A trigger that would cause a minor flush in someone else can set off a cascade of vasoconstriction followed by rebound vasodilation. That cascade is a migraine.

COMT is the enzyme responsible for breaking down dopamine, norepinephrine, and adrenaline once they’ve done their job. These neurotransmitters are critical for focus, mood, and the brain’s ability to suppress pain signals. Once your brain has used them, COMT needs to clear them so your nervous system can recalibrate.

The COMT Val158Met variant comes in three forms: fast (Val/Val), intermediate (Val/Met), and slow (Met/Met). Approximately 25% of people with European ancestry are homozygous slow (Met/Met). If you’re a slow COMT, you clear these pain-suppressing neurotransmitters more slowly, which means pain signals amplify in your trigeminal system. Your brain has more difficulty shutting down the pain cascade once it starts. This doesn’t just make individual migraines worse, it makes you more susceptible to chronic migraine and medication overuse headache.

You may notice that caffeine, intense exercise, or high-stress situations trigger or worsen your migraines. That’s because they all spike dopamine and norepinephrine. If your COMT is slow, your system gets flooded and can’t clear them efficiently.

CACNA1A encodes a calcium channel in the brain’s neurons. Calcium is the signal that tells neurons when to fire. CACNA1A regulates how easily neurons in your cortex and brainstem cross the threshold from resting to firing. This matters enormously for migraines because migraine initiation involves a wave of neuronal hyperexcitability called cortical spreading depression.

Mutations in CACNA1A cause familial hemiplegic migraine, a rare form of migraine with aura that includes temporary paralysis. Even common variants in CACNA1A alter the threshold for cortical spreading depression, meaning your neurons are more likely to trigger this cascade spontaneously. If you carry a CACNA1A variant, your brain is neurologically more excitable than average. Your cortex needs less stimulation to initiate a migraine wave. Roughly 1 to 5 percent of people with familial migraine carry functional variants.

If you get migraine aura (flashing lights, blind spots, tingling), or if your migraines tend to be triggered by sensory overload, CACNA1A may be part of your picture.

NOS3 encodes endothelial nitric oxide synthase, the enzyme that produces nitric oxide directly in blood vessel walls. Unlike MTHFR (which is involved in the broader methylation cycle), NOS3 is the direct manufacturer of the molecule that tells vessels to relax. Nitric oxide is one of the most potent vasodilators in the body.

The NOS3 Glu298Asp variant (rs1799983) is carried by approximately 30 to 40 percent of people. Carriers of this variant produce less nitric oxide, meaning their blood vessels have a harder time responding to the demand for relaxation and blood flow. This creates the same problem as MTHFR: your cerebral blood vessels become less responsive and more reactive to triggers. When a trigger hits, they constrict more readily and rebound more aggressively.

If you’re a NOS3 variant carrier, you may notice your migraines are worse during physical exertion, sexual activity, or any situation that demands rapid blood vessel dilation. Your vessels can’t keep up with the metabolic demand.

SLC6A4 encodes the serotonin transporter, the protein that recycles serotonin from the synapse back into neurons so it can be reused. Serotonin is central to migraine biology. It regulates blood vessel tone, pain perception, mood, and sleep. When serotonin signaling is stable, migraines are less likely. When it fluctuates, migraines accelerate.

The SLC6A4 5-HTTLPR promoter region comes in long and short variants. Approximately 40 percent of people carry at least one short allele. The short allele reduces the expression of the serotonin transporter, meaning your brain has lower serotonin availability and slower serotonin recycling. This creates a state of chronic serotonin insufficiency. Your brain can’t stabilize serotonin signaling the way it should. This is why many migraine sufferers respond to SSRIs (which increase serotonin availability), but the effect often takes weeks because the underlying transporter deficiency doesn’t change.

If you’re a SLC6A4 short allele carrier, you may notice your migraines cluster around hormonal cycles, stress spikes, or sleep disruption, because all of these deplete serotonin further.

TRPM8 encodes a channel protein on sensory neurons that detects cold and menthol. This channel is part of the trigeminal nerve, which is the primary nerve involved in migraine sensation and pain. TRPM8 controls how easily the sensory neurons of the trigeminal system activate in response to cold or chemical irritants.

Variants in TRPM8 are associated with migraine susceptibility based on genome-wide association studies. Carriers of certain variants have a lower threshold for trigeminal activation. Your sensory neurons are more easily triggered by temperature changes, wind, or irritants that wouldn’t bother someone else. Roughly 15 to 20 percent of the population carry variants that shift this threshold. The mechanism is not yet fully understood, but the association with migraine is consistent.

If you’re a TRPM8 variant carrier, you may notice that weather changes, cold exposure, or air conditioning triggers your migraines more reliably than other factors. Cold water on your face, ice cream, or even thinking about cold can sometimes provoke a migraine.