Acute inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocyte count (WBC) have low specificity for diagnosis, particularly in the setting of a profound systemic inflammatory response (e.g. rheumatoid arthritis, Crohn’s disease, systemic lupus erythematosus, etc.). The gene discussed is CRP; the disease is Crohn disease.