In this sense, GCA can be grouped with vasculitides such as ANCA-associated vasculitis or IgA vasculitis into class II diseases associated with HLA-DRB1 alleles14, 15, while TAK and Behçet’s disease would represent archetypal class I diseases7, 16. The gene discussed is HLA-DRB1; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.