GTP cyclohydrolase and tetrahydrobiopterin regulate pain sensitivity and persistence. C allele associated with higher tolerance to pain.[PMID 17057711]
Polymorphisms in the GTP cyclohydrolase gene (GCH1) are associated with ratings of capsaicin pain. C allele associated with higher tolerance to pain.[PMID 19081190]
[PMID 17343757] Lack of influence of GTP cyclohydrolase gene (GCH1) variations on pain sensitivity in humans.
[PMID 23322459] Association of guanosine triphosphate cyclohydrolase 1 gene polymorphisms with fibromyalgia syndrome in a Korean population.