Despite the presence of different patterns of genetic alterations in these hotspot genes, the fallouts of these studies did not nominate a specific gene alteration in association with the development of PC since different studies showed a variable prevalence of TP53, SPOP and PIK3CA mutations or alterations in the PC cases (Bookstein et al., 1993; Carroll et al., 1993; Mirchandani et al., 1995; Edwards et al., 2003b; Müller et al., 2007; Sun et al., 2009; Taylor et al., 2010; Barbieri et al., 2012; Abeshouse et al., 2015). This evidence concerns the gene PIK3CA and pachyonychia congenita.