FUT2 Genetic Variants and Reported Respiratory and Gastrointestinal Illnesses During Infancy

Background Fucosyltransferase 2 (FUT2) controls the production of digestive and respiratory epithelia of histo-blood group antigens involved in the attachment of pathogens. The aim of our study was to relate FUT2 variants to reported gastrointestinal and respiratory illnesses in infancy. Methods In the Southampton Women's Survey, FUT2 genetic variants (single-nucleotide polymorphisms [SNPs] rs601338 and rs602662) were genotyped in 1831 infants and related to infant illnesses, after adjustment for sex, breastfeeding duration, and potential confounders. Results For FUT2 SNP rs601338, the risk ratios for 1 bout of diarrhea during ages 6-12 months and ages 12-24 months per additional risk (G) allele were 1.23 (95% confidence interval [CI], 1.08-1.4; P = .002) and 1.41 (95% CI, 1.24-1.61; P = 1.7 x 10(-7)), respectively; the risk ratio for 1 diagnosis of a lower respiratory illness (ie, pneumonia or bronchiolitis) during ages 12-24 months per additional G allele was 2.66 (95% CI, 1.64-4.3; P = .00007). Similar associations were found between rs602662 and gastrointestinal and respiratory illnesses, owing to the high linkage disequilibrium with rs601338 (R-2 = 0.92). Longer breastfeeding duration predicted a lower risk of diarrhea, independent of infant FUT2 genotype. Conclusions We confirmed that FUT2 G alleles are associated with a higher risk of infant gastrointestinal illnesses and identified novel associations with respiratory illnesses. FUT2 locus variants need consideration in future studies of gastrointestinal and respiratory illnesses among infants. The study confirms the role of fucosyltransferase 2 in the risk of reported gastrointestinal illnesses in a United Kingdom population and reports novel associations with respiratory illnesses and comorbidities. Breastfeeding has a protective role against the risk of illnesses, independent of FUT2 variants.