A genome-wide association meta-analysis of diarrhoeal disease in young children identifies FUT2 locus and provides plausible biological pathways.

Mariona Bustamante, Marie Standl, Quique Bassat, Natalia Vilor-Tejedor, Carolina Medina-Gomez, Carolina Bonilla, Tarunveer S Ahluwalia, Jonas Bacelis, Jonathan P Bradfield, Carla M T Tiesler, Fernando Rivadeneira, Susan Ring, Nadja H Vissing, Nadia R Fink, Astanand Jugessur, Frank D Mentch, Ferran Ballester, Jennifer Kriebel, Jessica C Kiefte-de Jong, Helene M Wolsk, Sabrina Llop, Elisabeth Thiering, Systke A Beth, Nicholas J Timpson, Josefine Andersen, Holger Schulz, Vincent W V Jaddoe, David M Evans, Johannes Waage, Hakon Hakonarson, Struan F A Grant, Bo Jacobsson, Klaus Bønnelykke, Hans Bisgaard, George Davey Smith, Henriette A Moll, Joachim Heinrich, Xavier Estivill, Jordi Sunyer

More than a million childhood diarrhoeal episodes occur worldwide each year, and in developed countries a considerable part of them are caused by viral infections. In this study we aimed to search for genetic variants associated with diarrhoeal disease in young children by meta-analyzing genome-wide association studies, and to elucidate plausible biological mechanisms.The study was conducted in the context of the Early Genetics and Lifecourse Epidemiology (EAGLE) consortium. Data about diarrhoeal disease in two time windows (around one year of age and around two years of age) was obtained via parental questionnaires, doctor interviews or medical records. Standard quality control and statistical tests were applied to the 1000 Genomes imputed genotypic data.The meta-analysis (N=5,758) followed by replication (N=3,784) identified a genome-wide significant association between rs8111874 and diarrhoea at age one year. Conditional analysis suggested that the causal variant could be rs601338 (W154X) in the FUT2 gene. Children with the A allele, which results in a truncated FUT2 protein, had lower risk of diarrhoea. FUT2 participates in the production of histo-blood group antigens and has previously been implicated in the susceptibility to infections, including Rotavirus and Norovirus Gene-set enrichment analysis suggested pathways related to the histo-blood group antigen production, and the regulation of ion transport and blood pressure. Among others, the gastrointestinal tract, the immune and neuro-secretory systems were detected as relevant organs.In summary, this genome-wide association meta-analysis suggests the implication of the FUT2 gene in diarrhoeal disease in young children from the general population.