The genomic region spanning rs4265380 shows enhancer activity. The genomic region spanning rs4265380 shows enhancer activity. The reporter activity of rs4265380 compared with minimal promoter construct (minP) and normalised to Renilla internal control was measured by luciferase assays on HEK293T (n=3). The values of relative luciferase activity are expressed as mean±SEM. (P=0.0005, Student’s t-test). AS, ankylosing spondylitis. Matteo Vecellio et al. RMD Open 2018;4:e000628 Copyright © BMJ Publishing Group & EULAR. All rights reserved.