In conclusion, our data suggests that additive gene models of COX-2 -765, HIF-1α rs11549467, and TP53 rs9895829, as well as dominant gene models of DR rs2228570, CTLA-4 rs231775 and MTHFR rs1801133 are associated with PC risk. The gene discussed is PTGS2; the disease is pachyonychia congenita.