{{Rsnum
|rsid=8007201
|Gene=GCH1
|Chromosome=14
|position=54858130
|Orientation=plus
|GMAF=0.4518
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene_s=GCH1
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 34.5 | 50.4 | 15.0
| HCB | 36.0 | 49.3 | 14.7
| JPT | 33.0 | 49.1 | 17.9
| YRI | 7.5 | 33.3 | 59.2
| ASW | 7.0 | 47.4 | 45.6
| CHB | 36.0 | 49.3 | 14.7
| CHD | 39.4 | 45.0 | 15.6
| GIH | 55.4 | 38.6 | 5.9
| LWK | 12.8 | 43.1 | 44.0
| MEX | 29.3 | 58.6 | 12.1
| MKK | 14.1 | 46.2 | 39.7
| TSI | 58.8 | 35.3 | 5.9
| HapMapRevision=28
}}GTP cyclohydrolase and [[tetrahydrobiopterin]] regulate pain sensitivity and persistence. G allele associated with higher tolerance to pain.{{PMID|17057711}}

{{PMID Auto
|PMID=19081190
|Title=Polymorphisms in the GTP cyclohydrolase gene (GCH1) are associated with ratings of capsaicin pain.
|OA=1
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | Illumina Human 1M}}