For example, homozygosity of the nonsense FUT2 mutation rs601338G > A (G428A, W143X, Table 1) causes non-secretor status in 20% of Caucasians and has been found to be associated with Crohn’s disease, inflammatory bowel disease and infections such as Helicobacter pylori and certain genotypes of norovirus and rotavirus7–13. Here, FUT2 is linked to infection.