{{Rsnum
|rsid=752688
|Gene=GCH1
|Chromosome=14
|position=54844851
|Orientation=plus
|GMAF=0.2677
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Gene_s=GCH1
}}{{ population diversity
| geno1=(C;C)
| geno2=(C;T)
| geno3=(T;T)
| CEU | 62.5 | 32.8 | 4.7
| HCB | 33.3 | 51.1 | 15.6
| JPT | 35.6 | 44.4 | 20.0
| YRI | 54.8 | 41.9 | 3.2
| ASW | 0.0 | 0.0 | 0.0
| CHB | 33.3 | 51.1 | 15.6
| CHD | 0.0 | 0.0 | 0.0
| GIH | 0.0 | 0.0 | 0.0
| LWK | 0.0 | 0.0 | 0.0
| MEX | 0.0 | 0.0 | 0.0
| MKK | 0.0 | 0.0 | 0.0
| TSI | 0.0 | 0.0 | 0.0
| HapMapRevision=28
}}GTP cyclohydrolase and [[tetrahydrobiopterin]] regulate pain sensitivity and persistence. T allele associated with higher tolerance to pain.{{PMID|17057711}}

Polymorphisms in the GTP cyclohydrolase gene ([[GCH1]]) are associated with ratings of capsaicin pain. T allele associated with higher tolerance to pain.{{PMID|19081190|OA=1
}}

{{PMID Auto
|PMID=17343757
|Title=Lack of influence of GTP cyclohydrolase gene (GCH1) variations on pain sensitivity in humans.
|OA=1
}}

{{PMID Auto
|PMID=23322459
|Title=Association of guanosine triphosphate cyclohydrolase 1 gene polymorphisms with fibromyalgia syndrome in a Korean population.
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | FTDNA}}