title: Letter: Are homozygotes for HLA B27 more susceptible to ankylosing spondylitis?
mesh_terms: D005260:Female; D006680:HLA Antigens; D006649:Histocompatibility Antigens; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D013167:Spondylitis, Ankylosing / Q000235:genetics*
chemical_list: D006680:HLA Antigens; D006649:Histocompatibility Antigens