title: Low frequency of HLA-B27 in ankylosing spondylitis patients from Turkey.
abstract: OBJECTIVE
  Ankylosing spondylitis is strongly associated with HLA-B27. However, the strength of the association with HLA-B27 and the clinical features may vary in different parts of the world. The aim of this study is to compare the clinical features of AS and the frequencies of HLA-B27 and its alleles in patients from Turkey with other series.
  
  
  METHODS
  One hundred and twelve patients (72 male/40 female) fulfilling the modified New York criteria for the classification of AS and 55 (27 male/28 female) healthy controls were typed for HLA-B27 and allele frequencies by sequence specific primer (PCR/SSP) method and assessed for clinical manifestations.
  
  
  RESULTS
  Male to female ratio was 1.8, mean age at disease onset was 23.5 and 24.1% of patients reported juvenile onset of symptoms. Peripheral arthritis was seen in 52.7% of patients. Family history (p=0.01) and peripheral arthritis (p=0.02) were more frequent in females and spinal involvement in males. HLA-B27 was found to be positive in 70% of patients and associated with younger mean age, uveitis and shorter time elapsed from symptom to diagnosis. The frequency of HLA-B27 alleles associated with SpA was not different between ankylosing spondylitis patients and healthy controls.
  
  
  CONCLUSIONS
  Low frequency of HLA-B27 and clinical variations in ankylosing spondylitis may be due to different genetic and/or environmental factors in Turkey.
authors.affiliation: Maltepe University Medical Faculty, Department of Internal Medicine, Division of Rheumatology, Istanbul, Turkey. kasapogluesen@yahoo.com
authors.forename: Esen Kasapoglu
authors.initials: EK
authors.lastname: Gunal
authors.forename: Fatma Oguz
authors.initials: FO
authors.lastname: Sarvan
authors.forename: Sevil
authors.initials: S
authors.lastname: Kamali
authors.forename: Ahmet
authors.initials: A
authors.lastname: Gul
authors.forename: Murat
authors.initials: M
authors.lastname: Inanc
authors.forename: Mahmut
authors.initials: M
authors.lastname: Carin
authors.forename: Meral
authors.initials: M
authors.lastname: Konice
authors.forename: Orhan
authors.initials: O
authors.lastname: Aral
authors.forename: Lale
authors.initials: L
authors.lastname: Ocal
mesh_terms: D005260:Female; D005787:Gene Frequency; D015796:HLA-B27 Antigen / Q000235:genetics*; D006801:Humans; D008297:Male; D013167:Spondylitis, Ankylosing / Q000235:genetics*; D014421:Turkey
chemical_list: D015796:HLA-B27 Antigen