In line with that, mutations in ERCC1 (XPF), ERCC5 (XPG), and the components of TFIIH, including XPD, XPB, and TF2H5, lead to cerebro-oculo-facio-skeletal syndrome 4 (COFS4) (Kashiyama et al., 2013), xeroderma pigmentosum complementation group G (XP-G), COFS3 (Zafeiriou et al., 2001; Emmert et al., 2002; Drury et al., 2014), XP-D (Broughton et al., 1995), XP-B (Oh et al., 2006), and trichothiodystrophy 3 (TTD3) (Giglia-Mari et al., 2004), respectively, and all these disorders are reported to share a same feature—CS, in some cases. Here, ERCC2 is linked to Cowden syndrome 1.