Heterozygous GoF mutation of the PSTPIP1 gene causes the pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome and the PSTPIP1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome (no. 21 in Table 1 and Figure 1) (106, 107). The gene discussed is PSTPIP1; the disease is pyoderma gangrenosum.