Typical features for leading differential diagnoses and reasons that each was ruled out are discussed. CRP: C-reactive protein, ESR: erythrocyte sedimentation rate, SLE: systemic lupus erythematosus, ANA: antinuclear antibodies, IBD: inflammatory bowel disease, GU: genitourinary, dsDNA: double-stranded DNA. This evidence concerns the gene CRP and irritable bowel syndrome.