title: Clinical and Imaging Signs of Spondyloarthritis in First-Degree Relatives of HLA-B27-Positive Ankylosing Spondylitis Patients: The Pre-Spondyloarthritis (Pre-SpA) Cohort Study.
abstract: To investigate whether seemingly healthy first-degree relatives of patients with ankylosing spondylitis (AS) have clinical, laboratory, or imaging features of spondyloarthritis (SpA).
  
  
  
  First-degree relatives (ages 18-40 years) of HLA-B27-positive AS patients were included in the pre-spondyloarthritis (Pre-SpA) cohort, a prospective inception cohort study. Clinical, biologic, and imaging features were recorded. First-degree relatives were classified according to several sets of SpA classification criteria.
  
  
  
  We report baseline features of 51 first-degree relatives included in this study. Twenty-nine (57%) had back pain, 2 (4%) had psoriasis, 1 (2%) had inflammatory bowel disease, and 1 (2%) had uveitis. Three (6%) had low-grade sacroiliitis, 1 (2%) had cervical syndesmophytes on radiography, and 10 (20%) had bone marrow edema on magnetic resonance imaging of the sacroiliiac joints. Seventeen of 51 first-degree relatives (33%) fulfilled SpA classification criteria: 7 (14%) fulfilled both Assessment of SpondyloArthritis international Society (ASAS) axial SpA and European Spondylarthropathy Study Group (ESSG) classification criteria, 6 (12%) fulfilled only ASAS axial SpA classification criteria, and 4 (8%) fulfilled only ESSG classification criteria; 3 (6%) also fulfilled the Amor criteria. None fulfilled other SpA classification criteria. First-degree relatives fulfilling the ASAS axial SpA and/or ESSG classification criteria had more frequent inflammatory back pain, had a higher level of disease activity, and had more psoriasis. No differences were found in parameters of inflammation, peripheral and extraarticular disease other than psoriasis, and HLA-B27 positivity between those who did and those who did not fulfill the ASAS axial SpA and/or ESSG classification criteria. Four first-degree relatives (12%) who did not fulfill the ASAS axial SpA and/or ESSG classification criteria had imaging abnormalities suggestive of SpA.
  
  
  
  A substantial proportion of seemingly healthy first-degree relatives of HLA-B27-positive AS patients have clinical and/or imaging abnormalities suggestive of SpA. Thirty-three percent could be classified as having SpA. Further follow-up will show which first-degree relatives will develop clinically manifest SpA.
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Maureen C
authors.initials: MC
authors.lastname: Turina
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Janneke J
authors.initials: JJ
authors.lastname: de Winter
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jacky E
authors.initials: JE
authors.lastname: Paramarta
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Gamala
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Yeremenko
authors.affiliation: Tergooi Hospital, Hilversum, The Netherlands.
authors.forename: Marita N
authors.initials: MN
authors.lastname: Nabibux
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Landewé
authors.affiliation: Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands. d.l.baeten@amc.uva.nl.
authors.forename: Dominique L
authors.initials: DL
authors.lastname: Baeten
mesh_terms: D000293:Adolescent; D000328:Adult; D001416:Back Pain / Q000453:epidemiology*; D001855:Bone Marrow Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology; D015331:Cohort Studies; D004487:Edema / Q000000981:diagnostic imaging / Q000453:epidemiology; D005190:Family; D005260:Female; D015796:HLA-B27 Antigen / Q000235:genetics; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D054850:Osteophyte / Q000000981:diagnostic imaging / Q000453:epidemiology; D011446:Prospective Studies; D011565:Psoriasis / Q000453:epidemiology*; D011859:Radiography; D058566:Sacroiliitis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D025242:Spondylarthropathies / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013167:Spondylitis, Ankylosing / Q000235:genetics; D014605:Uveitis / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D015796:HLA-B27 Antigen