A recent GWAS study of 2687 Northern European Caucasian individuals with GPA and MPA suggested that GPA is associated with genetic variants of HLA-DP, SERPINA1 (encoding α1-antitrypsin), and PRTN3 (encoding PR3), whereas MPA is mainly associated with HLA-DQ [73]. Here, HLA-DPA1 is linked to microscopic polyangiitis.