Similar observations were made previously for some tumor cell lines in which telomerase activity is limited by levels of TR (Cristofari and Lingner, 2006; Xu and Blackburn, 2007), and might explain the tissue-specific impact of TERT and TR mutations in patients with dyskeratosis congenita (Batista et al., 2011; Strong et al., 2011; Armanios and Blackburn, 2012). This evidence concerns the gene TERT and dyskeratosis congenita.