The XPG nuclease was also foundto associate with and stabilize TFIIH, and mutations in the XPGgene related to an XP-G/CS phenotype abrogate the XPG–TFIIH interaction (Ito et al., 2007; Lehmann et al., 2014; Narita et al., 2015). The gene discussed is ERCC5; the disease is Cowden syndrome 1.