title: HLA-B27 homozygosity in seronegative spondyloarthropathies.
mesh_terms: D004198:Disease Susceptibility; D006680:HLA Antigens / Q000032:analysis*; D006720:Homozygote; D006801:Humans; D013167:Spondylitis, Ankylosing / Q000276:immunology*
chemical_list: D006680:HLA Antigens