Light touch causes pain? Your genes may be amplifying normal sensations.

The COMT gene controls how quickly your body breaks down dopamine, norepinephrine, and epinephrine, especially in the prefrontal cortex and pain-processing centers of your brain. In the trigeminal system, in your spinal cord, and throughout your central nervous system, COMT helps regulate whether pain signals get amplified or suppressed. It’s one of your body’s primary pain dimmers.

The Val158Met variant is carried by roughly 25-30% of people of European ancestry as a homozygous slow variant. Slow COMT means these catecholamines linger longer than they should. Your pain circuits stay activated and sensitized; normal touch registers as threatening. You’re stuck in a state of heightened neural excitability where pain signals don’t get properly dampened down.

You notice this as a constant low-level vigilance. Light pressure on your skin triggers shooting pains. Your nervous system feels like it’s stuck in “on” mode. You can’t relax because your pain-signaling neurons aren’t clearing their chemical messengers fast enough.

Your mu-opioid receptor is how your body’s own endogenous opioids lock in and produce analgesia. Endogenous opioids, including beta-endorphin and enkephalins, are your brain’s natural pain-relieving chemicals. Without a working opioid receptor, those chemicals can’t do their job. OPRM1 is the gene that codes for that receptor.

The A118G variant, present in roughly 10-15% of people of European ancestry (and 40% in East Asian populations), reduces the receptor’s sensitivity to endogenous opioids. Your body is producing the right pain-relief chemicals, but your receptors aren’t responding to them as strongly. It’s like turning down the volume on your body’s own pain-relief system. You have less natural analgesia at baseline.

This shows up as pain that feels disproportionate to the injury or stimulus. Others might get touched and feel nothing. You feel burning or sharp pain from the same touch. Your endogenous pain-relief system is simply less responsive.

MTHFR catalyzes the methylation cycle, which produces S-adenosylmethionine, or SAM. SAM is the methyl donor for hundreds of reactions throughout your body, including the synthesis of nitric oxide. Nitric oxide regulates blood vessel tone and is also a critical neurotransmitter in pain modulation. When MTHFR isn’t working well, your whole pain-signaling pathway gets disrupted.

The C677T variant, present in roughly 40% of European ancestry populations, reduces enzyme efficiency by 40-70%. Your body struggles to produce enough nitric oxide, and your pain-modulating methylation reactions slow down. This disrupts cerebrovascular tone and leaves your pain neurons less inhibited. Chronic pain and allodynia risk both increase significantly with this variant.

You experience this as constant low-grade pain amplification. Your nervous system feels raw. Even mild stimuli generate disproportionate pain signals because your natural pain-modulating neurotransmitters aren’t being produced efficiently enough.

Brain-derived neurotrophic factor is a growth factor that shapes which neural connections get strengthened and which get pruned. In pain circuits, BDNF makes pain-signaling synapses stronger and more responsive. Normally, BDNF helps you learn and adapt. In chronic pain, high BDNF activity can cement pain sensitivity into your nervous system. It’s like your nervous system is learning to be more sensitive.

The Val66Met variant, carried by roughly 30% of the population, is associated with reduced activity-dependent BDNF release and altered pain modulation. In people with this variant, pain-signaling synapses don’t strengthen quite as easily, but they also don’t weaken easily, leaving you stuck in a sensitized state. Your nervous system can’t reestablish normal pain thresholds once allodynia develops.

This feels like pain that has become embedded in your nervous system. Stimuli that used to be tolerable now trigger pain reflexively. Your nervous system has “learned” to be hypersensitive, and that learning doesn’t easily reverse.

TRPV1 is a sensory ion channel that detects heat, pain, and irritant chemicals like capsaicin. It’s present on nerve endings throughout your body and is one of the primary neurons that signals pain and temperature. When TRPV1 is working normally, it fires only at genuine threats. It’s a protective alarm system. But variants can lower the threshold at which it fires, making it oversensitive.

Variants in TRPV1 are present in roughly 25-30% of the population and include both gain-of-function and loss-of-function effects. Gain-of-function variants are especially relevant to allodynia: these variants lower the activation threshold for heat, pressure, and chemical pain signals, making normal touch feel burning hot or painful. Your nerve endings are firing pain signals at stimuli that shouldn’t trigger them at all.

You experience this as burning sensations, sharp pain from light pressure, and exaggerated responses to warmth. Your skin feels hypersensitive. Normal clothing, water temperature, or gentle contact generates real pain because your pain neurons are firing more easily than they should.

GCH1 is the first enzyme in the pathway that produces tetrahydrobiopterin, or BH4, a cofactor essential for the synthesis of pain-modulating neurotransmitters including serotonin, dopamine, and nitric oxide. Without enough BH4, your pain-dampening systems literally can’t operate. BH4 is also involved in the synthesis of levodopa and tetrahydrofolate, both critical for pain modulation.

Variants in GCH1 are present in roughly 15-20% of the population and directly influence pain sensitivity. People with GCH1 variants that reduce BH4 production have lower baseline capacity to synthesize pain-dampening neurotransmitters, leaving them more vulnerable to allodynia and central sensitization. Your body simply can’t produce enough of the chemical tools needed to suppress pain signals.

You notice this as widespread pain that doesn’t respond well to standard analgesics. Your pain circuits feel fundamentally hyperactive. No amount of rest or stress management can fully resolve it because the underlying neurotransmitter production capacity is constrained by your genes.