AP1S3 and generalized pustular psoriasis: Other genes with mutations identified in patients with generalized pustular psoriasis include the adaptor-related protein complex 1 subunit sigma 3 (AP1S3) [121], mutations in Myeloperoxidase (MPO) genes [122], Serpin Family A Member 1 (SERPINA1) and SERPINA3, TNIP1, and IL1RN [120].