rs10166942 — TRPM8

TRPM8 — The Cold Sensor at the Crossroads of Migraine and Metabolism

Transient receptor potential melastatin 8¹¹ Transient receptor potential melastatin 8
TRPM8 is a nonselective cation channel activated by temperatures below ~26 degrees C and by cooling compounds such as menthol and icilin. It belongs to the TRP superfamily of ion channels and is the principal cold thermosensor in mammals (TRPM8) is the body's primary cold-sensing ion channel, expressed in sensory neurons of the dorsal root ganglia²² dorsal root ganglia
Clusters of nerve cell bodies along the spinal cord that relay sensory information — including temperature, pain, and touch — from the periphery to the brain and trigeminal ganglia. The variant rs10166942 sits 950 base pairs upstream of the TRPM8 transcription start site and directly influences how much of this channel your sensory neurons produce. This regulatory position makes it one of the most robustly replicated migraine loci in all of human genetics — and an emerging link between cold sensation, pain processing, and metabolic thermogenesis.

The Mechanism

rs10166942 is a regulatory variant that alters transcription factor binding upstream of TRPM8. The C allele reduces TRPM8 expression from the chromosome that carries it. In human dorsal root ganglia tissue³³ human dorsal root ganglia tissue
Dourson AJ et al. Reduced TRPM8 expression underpins reduced migraine risk and attenuated cold pain sensation in humans. Sci Rep, 2019, carriers of the C allele showed 47-99% lower TRPM8 mRNA expression compared to the T-carrying chromosome. This translates directly into altered cold sensing: C allele carriers required significantly lower temperatures to reach cold pain threshold (3.3 degrees C vs 6.5 degrees C, P=0.017) and took longer to reach that threshold (48.5 seconds vs 30.5 seconds, P=0.007).

The mechanism linking reduced TRPM8 to migraine protection involves the trigeminal pain pathway⁴⁴ trigeminal pain pathway
The trigeminal nerve innervates the face, head, and meninges. Overactivation of trigeminal sensory neurons triggers release of CGRP and other neuropeptides, causing neurogenic inflammation and the throbbing pain of migraine. TRPM8 activation in trigeminal neurons promotes release of calcitonin gene-related peptide (CGRP)⁵⁵ calcitonin gene-related peptide (CGRP)
The dominant neuropeptide in migraine pathophysiology. CGRP dilates cranial blood vessels and promotes neurogenic inflammation. All FDA-approved preventive migraine antibodies target CGRP or its receptor, the central neuropeptide of migraine. Less TRPM8 expression means less CGRP release upon cold or environmental temperature changes — and less migraine susceptibility.

The Evidence

The first GWAS to achieve genome-wide significance⁶⁶ first GWAS to achieve genome-wide significance
Chasman DI et al. Genome-wide association study reveals three susceptibility loci for common migraine in the general population. Nat Genet, 2011 for rs10166942 included 5,122 migraineurs and 18,108 non-migraineurs, reporting an odds ratio of 0.85 (95% CI 0.82-0.89, P=5.5x10^-12) for the C allele. Gender-stratified analyses suggested the association may be stronger in women (meta-regression P=0.004). This was confirmed in a mega meta-analysis of 375,000 individuals⁷⁷ mega meta-analysis of 375,000 individuals
Gormley P et al. Meta-analysis of 375,000 individuals identifies 38 susceptibility loci for migraine. Nat Genet, 2016 and subsequently in a GWAS of 102,084 migraine cases⁸⁸ GWAS of 102,084 migraine cases
Hautakangas H et al. Genome-wide analysis of 102,084 migraine cases identifies 123 risk loci and subtype-specific risk alleles. Nat Genet, 2022.

Beyond migraine frequency, the T allele drives chronification. A study of 1,904 migraine patients⁹⁹ 1,904 migraine patients
Alonso-Blanco C et al. TRPM8 genetic variant is associated with chronic migraine and allodynia. J Headache Pain, 2019 found T carriers were significantly more likely to have chronic migraine (33.7% vs 25.8%, adjusted OR 1.62, P=0.004) and showed greater allodynia severity (3.5 vs 2.6 on standard scales, P<0.001).

Evolutionary Context and Population Variation

rs10166942 shows one of the most extreme latitudinal clines in the human genome. The T allele frequency ranges from 5% in Nigeria to 88% in Finland — an FST value in the top 0.02%¹⁰¹⁰ FST value in the top 0.02%
Key FM et al. Human local adaptation of the TRPM8 cold receptor along a latitudinal cline. PLoS Genet, 2018 of all human genetic variation. Ancient DNA evidence places the onset of selection approximately 26,000 years ago during the last glacial maximum, suggesting TRPM8 upregulation (T allele) was advantageous for cold adaptation in high-latitude environments. The evolutionary cost of enhanced cold sensing appears to be increased migraine susceptibility — a trade-off that explains why migraine prevalence is highest in northern European populations.

The Metabolic Connection

Beyond pain sensing, TRPM8 plays a surprising role in energy metabolism. Mouse studies¹¹¹¹ Mouse studies
Ma S et al. Activation of the cold-sensing TRPM8 channel triggers UCP1-dependent thermogenesis and prevents obesity. J Mol Cell Biol, 2012 demonstrated that TRPM8 activation triggers UCP1¹²¹² UCP1
Uncoupling protein 1, the hallmark protein of brown adipose tissue. UCP1 dissipates the mitochondrial proton gradient as heat instead of ATP, driving non-shivering thermogenesis-dependent thermogenesis in brown adipose tissue through PKA-mediated phosphorylation. Dietary menthol (a TRPM8 agonist) prevented high-fat-diet-induced obesity and glucose intolerance in wild-type mice — effects completely absent in both TRPM8-knockout and UCP1-knockout animals. A follow-up study¹³¹³ follow-up study
Rossato M et al. Dietary menthol-induced TRPM8 activation enhances WAT browning and ameliorates diet-induced obesity. Oncotarget, 2014 showed that menthol also promotes browning of white adipose tissue, upregulating UCP1, PGC1-alpha, and PRDM16 expression.

This creates an intriguing dual profile for rs10166942: the T allele that increases migraine risk may simultaneously support greater thermogenic capacity and metabolic flexibility — consistent with the selection pressures of ice-age Europe. The C allele that protects against migraine may correspond to reduced TRPM8-mediated thermogenesis, though direct human metabolic studies linking this specific SNP to body composition are still needed.