title: Striking prevalence of ankylosing spondylitis in "healthy" w27 positive males and females.
abstract: Ankylosing spondylitis is diagnosed once or twice in each 1000 males and one tenth as frequently in females, but the true prevalence is unknown. Indentification of genetic marker, HL-A W27, for susceptible persons has provided a tool facilitating epidemiologic studies and allowing identification of "control" populations without the marker. Evaluation by postal questionnaires, and pelvic radiography of 78 HL-A 27W-positive blood donors selected from a group of apparently healthy subjects revealed 14 who satisfied the criteria for definite ankylosing spondylitis. The prevalence was similar in both sexes. One hundred and twenty-six W27-negative controls matched for race, sex, and age failed to yield a single case. For a person of either sex with HL-A W27, there appears to be about a 20 per cent chance that ankylosing spondylitis will develop, suggesting a prevalence of 10 to 15 per thousand. Hitherto accepted figures may underestimate the frequency by a factor of 10 to 20.
mesh_terms: D000328:Adult; D000368:Aged; D001416:Back Pain / Q000453:epidemiology; D001782:Blood Donors; D002140:California; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D006649:Histocompatibility Antigens / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging; D013167:Spondylitis, Ankylosing / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics / Q000276:immunology
chemical_list: D006680:HLA Antigens; D006649:Histocompatibility Antigens