A genome-wide association study (GWAS) can reveal dozens, sometimes hundreds, of genetic variations linked to a disease or trait. The subsequent challenge is to discover the precise roles those variants play.
Such is the case of a gene called C1orf106 and inflammatory bowel disease (IBD). A 2011 GWAS flagged a C1orf106 variant as a risk factor for ulcerative colitis (a form of IBD). A subsequent Broad Institute-led sequencing study identified the variant as a mutation, dubbed *333F, that alters C1orf106's protein product.