Increased ergothioneine tissue concentrations in carriers of the Crohn’s disease risk-associated 503F variant of the organic cation transporter OCTN1

Accumulating evidence suggests that genetic susceptibility to Crohn’s disease (CD) is driven by loss-of-function mutations in established risk genes such as IBD5 , NOD2/CARD15 , ATG16L1 or IL23R conferring defects in the innate immune response.1 2 Within the IBD5 locus, a coding variant of the organic cation transporter OCTN1 ( SLC22A4 ) has been associated with the risk of CD in Caucasian populations.3 4 However, the causal involvement of OCTN1 in CD pathogenesis is unclear, because the OCTN1 variant is in linkage disequilibrium with other IBD5 alleles, in particular with a promoter variant of the carnitine transporter OCTN2 ( SLC22A5 ).3 We have previously demonstrated that the food ingredient ergothioneine (ET), not arising from mammalian metabolism or intestinal flora, represents the key substrate of OCTN15 and that the CD risk-associated variant 503F (1672T) exhibits a …