Failure to respond is defined as a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) of at least 4.0 and raised inflammatory markers (erythrocyte sedimentation rate (ESR) >25 mm/hour and/or C-reactive protein (CRP) >10.0 mg/L) [29]. The gene discussed is CRP; the disease is ankylosing spondylitis.