DSP and pachyonychia congenita: In addition, other candidate genes may need to be considered, including GJB6 encoding connexin 30,20 desmoglein 1 (DSG1),21 desmoplakin (DSP),22 keratin 9 (KRT9),17 and frizzled 6,23,24 mutations in that mimic some features of the PC phenotype and hence should be encompassed into the differential diagnosis of PC.