Your Family's Migraines Aren't Bad Luck. They're Genetic.

MTHFR is an enzyme that converts dietary folate into the active form your cells use for methylation reactions. Methylation is the process that regulates everything from DNA transcription to neurotransmitter production to vascular reactivity. When MTHFR works normally, your nervous system maintains stable blood vessel tone and optimal nitric oxide levels, both critical for migraine prevention.

The C677T variant, carried by roughly 40% of people with European ancestry, cuts MTHFR enzyme efficiency by 40-70%. When this variant is present, your cells can’t convert regular B vitamins into their active methylated forms efficiently. The result is impaired vascular regulation and elevated homocysteine, both direct migraine triggers. If both your parents carry the variant, you likely inherited it from at least one, and your migraine threshold is significantly lower.

You probably feel this as migraines that come on after stress, during hormonal shifts, or after nights without enough sleep. Your blood vessels are already slightly dysregulated by the genetic variant. Any additional stressor tips you over the edge. Your family pattern makes sense now: everyone carrying the C677T variant has a lower threshold, so migraines show up earlier and more frequently in your family than in the general population.

COMT is the enzyme that breaks down catecholamines (dopamine, norepinephrine, epinephrine) after they’ve done their job. In your trigeminal nerve, the nerve system that carries migraine pain, COMT controls how long pain-modulating signals persist. When COMT clears catecholamines quickly, pain signals quiet down. When it clears them slowly, pain persists and amplifies.

The Val158Met variant is common: roughly 25% of people with European ancestry are homozygous for the slow-clearing Met allele. Slow COMT means catecholamines linger longer, amplifying pain signal transmission in the trigeminal system and worsening both migraine severity and frequency. If your family carries slow COMT variants, your migraines are likely more intense than they would be with faster COMT, and they’re slower to resolve once they start.

You’ll recognize this genetically if your migraines are triggered or worsened by stress (catecholamine flood), caffeine (more catecholamine load), or loud environments. Your body struggles to downregulate the pain signal once it fires. Your siblings with the same variant probably describe similar patterns. This is why caffeine avoidance works so dramatically for some migraine sufferers and barely matters for others.

CACNA1A encodes a calcium channel in neurons. Calcium flow through these channels controls how easily your brain cells fire electrical signals. When calcium channels work normally, your neurons maintain a stable firing threshold. When CACNA1A variants are present, that threshold drops, and neurons fire more easily and more intensely.

Roughly 1-5% of familial migraine cases carry CACNA1A mutations, but in families where they do appear, they’re strongly penetrant. CACNA1A variants lower the cortical spreading depression threshold, making migraines, especially migraines with aura, far more likely to occur. If you or multiple family members experience visual aura before the migraine pain, there’s a real possibility CACNA1A is involved. This is the gene most strongly linked to familial hemiplegic migraine.

If this is your family’s gene, you probably notice that migraines come on suddenly and with less obvious provocation than other people’s migraines seem to. The firing threshold is just lower. Stress, light, menstrual cycle, sleep deprivation, weather changes all matter, but the underlying vulnerability is neuronal. This is also why standard triptans sometimes fail for you; your problem isn’t just vasoconstriction, it’s excessive neuronal firing.

NOS3 produces nitric oxide (NO), a molecule that controls vascular tone. Nitric oxide tells blood vessels to relax and dilate. When NOS3 works optimally, your blood vessels maintain flexible, stable tone. When NOS3 variants reduce its function, nitric oxide availability drops, and your blood vessels become more reactive and less stable.

The Glu298Asp variant is carried by roughly 30-40% of the population. This variant reduces nitric oxide production, altering cerebrovascular tone and making migraines more likely when vascular triggers are present. If your family includes multiple people with migraines triggered by weather changes, altitude, or intense exercise, you’re likely all carrying NOS3 variants that impair your vascular stability.

You’ll feel this as migraines that come on after physical exertion, during barometric pressure shifts, or when you go to higher altitudes. Your blood vessels lack the nitric oxide cushion they need to adapt smoothly to changes in blood flow demand or atmospheric pressure. Other people’s vessels adjust; yours overshoot. The migraine is the result of that vascular dysregulation.

SLC6A4 encodes the serotonin reuptake transporter. This protein sits on nerve cells and pulls serotonin back out of synapses once the signal has been transmitted. Serotonin is central to migraine biology; it regulates vasoconstriction, pain processing, and mood stability. When SLC6A4 works normally, serotonin is recycled efficiently, and migraine triggers stay dormant.

The 5-HTTLPR short allele variant is carried by roughly 40% of the population in at least one copy. The short allele reduces serotonin transporter expression, lowering serotonin availability in brain synapses and triggering the vasoconstriction-vasodilation cycles central to migraine. If your family includes people whose migraines worsen during depressive episodes or menstrual cycles (both low-serotonin states), SLC6A4 is likely involved.

You might notice your migraines cluster around mood changes, hormonal fluctuations, or seasonal shifts. Your serotonin system is already running lean. Any additional hit to serotonin availability (stress, menstruation, light deprivation) pushes you into migraine. This is also why some people’s migraines respond dramatically to SSRIs and others don’t; if SLC6A4 isn’t your bottleneck, increasing serotonin reuptake won’t help.

TRPM8 is a sensory ion channel that detects cold and menthol. It sits on trigeminal neurons, the same neurons that carry migraine pain signals. When TRPM8 works normally, it modulates sensory input from your face and head, keeping that input stable and filtered. When TRPM8 variants are present, the trigeminal neurons become hypersensitive to temperature and sensory stimuli.

TRPM8 variants are associated with migraine susceptibility in genome-wide association studies, carried by roughly 15-20% of populations. These variants lower the activation threshold of trigeminal sensory neurons, making them fire more easily in response to temperature shifts, tactile pressure, or light. If your family’s migraines are triggered by cold exposure, ice cream, or sudden temperature changes, TRPM8 is likely part of your genetic profile.

You’ll recognize this as migraines triggered by touching your forehead, wearing a tight headband, or going from a warm room into cold air. Your trigeminal neurons are primed to fire. A stimulus that would barely register in someone with normal TRPM8 sends you into a migraine. This is also why ice packs, which help some people’s migraines, might trigger yours.