ERCC3 and Cowden syndrome 1: Mutations in the XPB (ERCC3) and XPD (ERCC2) genes can lead to TTD, XP, CS, and XP combined with CS (XPCS) (Coin et al., 1999; Dubaele et al., 2003; Oh et al., 2006; Oksenych and Coin, 2010).