TiO 2 nanoparticles abrogate the protective effect of the Crohn's disease-associated variation within the PTPN22 gene locus.

Our findings indicate that the consumption of TiO nanoparticles might have adverse effects on the gastrointestinal health of individuals carrying the PTPN22 variant. This demonstrates that environmental factors interact with genetic risk variants and can reverse a protective mechanism into a disease-promoting effect.