The study investigated the development of PC in three out of 16 CP patients with the N34S mutation (18.8%), while only three of 216 CP patients without the SPINK1 mutation (1.4%) developed PC, indicating that the N34S mutation of the SPINK1 gene may be a significant risk factor for the development of PC in patients with CP. This evidence concerns the gene SPINK1 and pachyonychia congenita.