title: The Frequency of HLA-B27 in a Colombian Population with Signs of Spondyloarthritis.
abstract: BACKGROUND
  The strong association between HLA-B27 and spondyloarthritis (SpA) has demonstrated that typing the HLA-B27 antigen is a crucial step in diagnosis and aids in defining the progression and severity of disease.
  
  
  OBJECTIVE
  To describe the frequency of HLA-B27 in Colombian individuals with clinical manifestations associated with SpA.
  
  
  METHODS
  We retrospectively analyzed 4109 HLA-B27 typing requests to the Hospital Militar Central and the Instituto de Referencia Andino from Colombian individuals with clinical signs suggestive of SpA between 2009 and 2012. We used basic digital cytometry followed by Polymerase Chain Reaction with sequence specific primers when confirmation was needed. We determined the frequency of HLA-B27 in the population and levels of association of HLA-B27 with SpA.
  
  
  RESULTS
  Our population included 1585 men (36.8%) and 2524 women (61.4%). The predominant age range was between 19 and 45 years (49.9%). The majority (95.4%) of the study population came from the Andean region and eastern plains. The most frequent clinical manifestations were peripheral. Only a small fraction (12.1%) of the 4109 subjects was HLA-B27 positive. Of those, 56.9% were male, and 54.7% were between 19 and 45 years old. In contrast, when rheumatologists referred the HLA B27, 64% were found to be positive.
  
  
  CONCLUSIONS
  The frequency of the HLA-B27 allele in individuals with clinical signs suggestive of SpA was low, in accordance with the lower prevalence found in Colombian patients diagnosed with SpA compared to American and European population.
authors.affiliation: Spondyloarthropaty Group, Division of Rheumatology, Hospital Militar Central, Bogota, Colombia.|UIBO Institute (Oral Basic Research Unit), Universidad El Bosque, Bogota, Colombia.|Instituto de Referencia Andino, Bogota, Colombia.|Faculty of Medicine, Universidad Militar Nueva Granada, Bogota, Colombia.
authors.forename: Consuelo
authors.initials: C
authors.lastname: Romero-Sanchez
authors.affiliation: UIBO Institute (Oral Basic Research Unit), Universidad El Bosque, Bogota, Colombia.
authors.forename: Lorena
authors.initials: L
authors.lastname: Chila-Moreno
authors.affiliation: Instituto de Referencia Andino, Bogota, Colombia.|Institute of Human Genetics, Faculty of Medicine, Pontificia Universidad Javeriana, Bogota, Colombia.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gómez
authors.affiliation: Instituto de Referencia Andino, Bogota, Colombia.
authors.forename: Maria Consuelo
authors.initials: MC
authors.lastname: Casas G
authors.affiliation: Faculty of Medicine, Universidad Militar Nueva Granada, Bogota, Colombia.
authors.forename: Wilson
authors.initials: W
authors.lastname: Bautista-Molano
authors.affiliation: Institute of Human Genetics, Faculty of Medicine, Pontificia Universidad Javeriana, Bogota, Colombia.|Faculty of Medicine, Universidad de la Sabana, Bogota, Colombia.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Briceño
authors.affiliation: Faculty of Medicine, Universidad de la Sabana, Bogota, Colombia.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Rueda
authors.affiliation: UIBO Institute (Oral Basic Research Unit), Universidad El Bosque, Bogota, Colombia.
authors.forename: Juliette
authors.initials: J
authors.lastname: De Avila
authors.affiliation: Faculty of Medicine, Universidad de la Sabana, Bogota, Colombia.|Spondyloarthropaty Group. Universidad de la Sabana-Division of Rheumatology and Immunology, Hospital Militar Central, Bogota, Colombia.
authors.forename: John
authors.initials: J
authors.lastname: Londono
authors.affiliation: Spondyloarthropaty Group, Division of Rheumatology, Hospital Militar Central, Bogota, Colombia.|Faculty of Medicine, Universidad Militar Nueva Granada, Bogota, Colombia.
authors.forename: Rafael
authors.initials: R
authors.lastname: Valle-Onate
mesh_terms: D000328:Adult; D003105:Colombia / Q000453:epidemiology; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010641:Phenotype; D015995:Prevalence; D012189:Retrospective Studies; D025241:Spondylarthritis / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology; D055815:Young Adult
chemical_list: D015796:HLA-B27 Antigen
keywords: Flow cytometry; HLA-B27; ankylosing spondylitis; autoimmune diseases; polymerase chain reaction; population.