TY - JOUR T1 - <em>ERAP2</em> is associated with ankylosing spondylitis in <em>HLA-B27</em>-positive and <em>HLA-B27-</em>negative patients JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis SP - 1627 LP - 1629 DO - 10.1136/annrheumdis-2015-207416 VL - 74 IS - 8 AU - Philip C Robinson AU - Mary-Ellen Costello AU - Paul Leo AU - Linda A Bradbury AU - Kelly Hollis AU - Adrian Cortes AU - Seunghun Lee AU - Kyung Bin Joo AU - Seung-Cheol Shim AU - Michael Weisman AU - Michael Ward AU - Xiaodong Zhou AU - Henri-Jean Garchon AU - Gilles Chiocchia AU - Johannes Nossent AU - Benedicte A Lie AU - Øystein Førre AU - Jaakko Tuomilehto AU - Kari Laiho AU - Lei Jiang AU - Yu Liu AU - Xin Wu AU - Dirk Elewaut AU - Ruben Burgos-Vargas AU - Lianne S Gensler AU - Simon Stebbings AU - Nigil Haroon AU - Juan Mulero AU - Jose Luis Fernandez-Sueiro AU - Miguel A Gonzalez-Gay AU - Carlos Lopez-Larrea AU - Paul Bowness AU - Karl Gafney AU - John S Hill Gaston AU - Dafna D Gladman AU - Proton Rahman AU - Walter P Maksymowych AU - Huji Xu AU - Irene E van der Horst-Bruinsma AU - Chung-Tei Chou AU - Raphael Valle-Oñate AU - María Consuelo Romero-Sánchez AU - Inger Myrnes Hansen AU - Fernando M Pimentel-Santos AU - Robert D Inman AU - Javier Martin AU - Maxime Breban AU - David Evans AU - John D Reveille AU - Tae-Hwan Kim AU - B Paul Wordsworth AU - Matthew A Brown Y1 - 2015/08/01 UR - http://ard.bmj.com/content/74/8/1627.abstract N2 - The association of endoplasmic reticulum aminopeptidase 2 (ERAP2) with ankylosing spondylitis (AS) was recently described in the large International Genetics of AS Consortium Immunochip study.1 Variants in ERAP2 have also been associated with inflammatory bowel disease, psoriasis, acute anterior uveitis and birdshot chorioretinopathy.2–5 Subsequent investigation demonstrated an association of ERAP2 with AS which was present when one conditioned on one of the two independent haplotypes of ERAP1 associated with AS or when HLA-B27-negative patients were analysed separately.1 These two analyses provide analogous evidence for the association of ERAP2 with AS in HLA-B27-negative cases because of the genetic interaction between HLA-B27 and the AS-associated ERAP1 variants in AS cases. ERAP1 and ERAP2 are located on chromosome 5q15 in the opposite orientation. The locus is challenging to analyse because of the strong linkage disequilibrium (LD) across the locus and the epistasis between ERAP1 and HLA-B alleles associated with AS. We therefore sought to investigate the association of ERAP2 with AS in HLA-B27-positive patients.6 This is of clinical importance because functional studies … ER -