Your Migraines Have a Genetic Cause. Here's Why.

MTHFR encodes methylenetetrahydrofolate reductase, the enzyme responsible for converting dietary folate and B vitamins into their active, usable forms in every cell. This process, called methylation, is the foundation for hundreds of critical functions: DNA synthesis, neurotransmitter production, immune regulation, and crucially for migraine, nitric oxide production and homocysteine metabolism. When MTHFR is working normally, your cells are constantly recycling B vitamins into the exact chemical forms they need.

The MTHFR C677T variant, carried by approximately 40% of people of European ancestry, reduces the enzyme’s efficiency by 40 to 70%. This means your cells are converting B vitamins at a fraction of normal speed. The consequence cascades quickly: you accumulate homocysteine, produce less nitric oxide, and lose the ability to regulate your blood vessel tone properly. Your brain becomes hypersensitive to triggers because the vascular regulatory system that normally protects it is compromised.

If you have this variant, your migraines often come with aura because your cerebral blood vessels are locked in a state of instability. You can’t vasodilate smoothly, and when cortical spreading depression (the electrical event that produces aura) occurs, your dysregulated vessels amplify the cascade. You may also notice that your migraines cluster around times of high stress or poor sleep, because methylation demand increases and your already-impaired enzyme falls further behind.

CACNA1A encodes a calcium channel that sits on the membrane of neurons throughout your brain. Calcium flowing through these channels is the critical signal for neuronal firing: when a neuron is stimulated, calcium rushes in, triggering an electrical impulse. CACNA1A controls the precise sensitivity of this system. In people with normal variants, neurons fire when they should and stay quiet when they should. The channel opens and closes with exquisite timing.

CACNA1A variants associated with migraine, particularly those found in familial hemiplegic migraine, alter this channel’s function in ways that lower the threshold for neuronal firing. Approximately 1 to 5% of people with familial migraine carry these variants. Your neurons become hair-trigger sensitive; they fire more easily and with less provocation, and once the cascade starts, it spreads more readily across cortical tissue. This is why cortical spreading depression, the electrical wave that produces migraine aura, is so easily triggered in people with CACNA1A variants.

If you carry a CACNA1A variant, your migraines often begin with a clear aura: visual disturbance, tingling, sometimes even temporary weakness. The aura itself reflects abnormal electrical activity spreading across your cortex. You may find that the aura is more consistent and reproducible than in people without the variant, because your threshold for triggering it is so much lower. You may also notice that your migraines are more frequent and severe than in family members without the variant, or that they began earlier in life.

COMT encodes catechol-O-methyltransferase, the enzyme responsible for breaking down catecholamines: dopamine, norepinephrine, and epinephrine. These are the brain’s main stress and arousal molecules. They regulate pain signaling through the trigeminal system, the bundle of nerves responsible for migraine pain. In a well-functioning COMT system, catecholamines are produced, do their job, and are quickly cleared. Your pain circuits stay regulated. Your stress response activates and deactivates smoothly.

The COMT Val158Met variant results in slower catecholamine breakdown. Approximately 25% of people of European ancestry are homozygous for the slow variant (Met/Met). Catecholamines linger in your trigeminal system longer, amplifying pain signaling and lowering your pain threshold. This means triggers that might cause mild discomfort in someone with fast COMT become full migraines in you. Stress becomes catastrophic. Hormonal shifts, caffeine, sleep changes, all things that modulate catecholamines, become potent migraine triggers.

If you have slow COMT, your migraines may be dramatically worsened by caffeine, stress, and stimulant use because these all raise catecholamines and your system can’t clear them fast enough. You may find that your migraines cluster around stressful periods or that you’re exquisitely sensitive to weather changes and barometric pressure shifts, which trigger catecholamine release. You may also have low pain tolerance in general, making the migraine pain itself feel more severe than others report.

NOS3 encodes endothelial nitric oxide synthase, the enzyme that produces nitric oxide in the lining of your blood vessels. Nitric oxide is one of the body’s most powerful vasodilators: it tells blood vessel smooth muscle to relax, allowing vessels to widen and maintain healthy blood flow. It also regulates platelet aggregation, preventing blood clots. In healthy vessels, a constant low level of nitric oxide production keeps everything flowing smoothly and vessels responsive to the body’s needs.

The NOS3 Glu298Asp variant, carried by approximately 30 to 40% of the population, reduces nitric oxide production. Your blood vessels lose their ability to dilate smoothly and maintain optimal tone, creating chronic mild vasoconstriction and reduced cerebral blood flow. This makes your brain’s vascular system less stable and more prone to the chaotic constriction and dilation cycles that characterize migraine. Your vessels are less responsive to signals to relax, so when triggers activate them, they can’t regulate smoothly.

If you have the NOS3 variant, your migraines often feel vascular: the throbbing quality may be pronounced. You may notice that your migraines are worsened by dehydration, heat, or anything that stresses your cardiovascular system. You may also have a history of high blood pressure or poor blood flow, because impaired nitric oxide production affects systemic vascular tone, not just cerebral vessels. Your migraines may improve in cooler environments or with rest.

SLC6A4 encodes the serotonin transporter, the protein responsible for recycling serotonin back into nerve terminals after it’s done signaling. Serotonin is central to migraine biology: it regulates blood vessel tone, modulates pain perception, controls mood and sleep, and influences the threshold for cortical spreading depression. In healthy brains, serotonin is released, transmits its signal, and is rapidly recycled back for reuse. The cycle repeats thousands of times per second.

The SLC6A4 5-HTTLPR short allele, carried by approximately 40% of the population in at least one copy, reduces the efficiency of serotonin recycling. Less serotonin is available to your neurons between firing events, causing chronic low serotonin signaling in your trigeminal system and brainstem. Low serotonin availability is a core feature of migraine pathophysiology: it reduces pain inhibition, destabilizes blood vessel tone, and lowers the threshold for cortical spreading depression and aura.

If you carry the short allele, your migraines may be strongly linked to mood or hormonal shifts, because serotonin fluctuations affect both. You may notice migraines cluster before your period, during stressful periods, or when you’re feeling low. Your migraines may improve slightly with SSRIs (which block serotonin reuptake, increasing availability), though the effect is often modest. You may also have a personal or family history of depression or anxiety, because the serotonin transporter dysfunction affects mood as well as migraine.

TRPM8 encodes a calcium channel on sensory neurons that detects cold and menthol. These channels sit on the trigeminal nerve endings that innervate your face, head, and meninges. When activated, they send cold-sensing signals to your brain. TRPM8 is also activated by pressure and certain chemical compounds. In normal function, these channels provide sensory information about temperature and touch without causing pain or migraine.

TRPM8 variants associated with migraine susceptibility, identified in genome-wide association studies, alter channel function in ways that increase trigeminal sensory neuron activation. Approximately 15 to 20% of the population carry variants associated with increased migraine risk. Your trigeminal nerves become hypersensitive to temperature changes, pressure, and other stimuli, firing more readily and more intensely when provoked. This lowers the barrier between normal sensation and pain, making your trigeminal system more reactive overall.

If you have TRPM8 variants, you may notice that temperature changes are strong migraine triggers: exposure to cold or even entering an air-conditioned space can spark an attack. You may be sensitive to pressure on your head or neck, finding that tight hats, ponytails, or tension headaches easily escalate into migraines. You may also find that menthol-containing products, which activate TRPM8 channels, can either help (if applied topically to desensitize) or worsen your migraines, depending on the specific variant and individual response.