TERC and idiopathic pulmonary fibrosis: In fact, three of the loci with the greatest effect sizes on risk fall near TERT, TR (also known as TERC), and RTEL1, the regulator of telomere elongation helicase 1; importantly, rare mutations in all three of these genes also cause autosomal dominant forms of IPF (18, 19, 25, 40) (FIGURE 4B and TABLE 1).