017, Table 1) compared to the control group (three IDH inhibitor heterozygous sequencing variants in 600 individuals, allele frequency 0.003, P = 0.0007). Reanalysis of the cirrhosis-associated gene mutations in frozen liver biopsies of two patients verified that these telomerase germline mutations were also detectable in liver (data not shown). Subdividing the control cohort into (1) healthy controls without chronic liver disease (n = 473) and (2) chronic liver disease patients without progression toward cirrhosis (n = 127) revealed that both subgroups exhibited significantly lower allele frequencies of telomerase mutations compared to the cirrhosis group (P = 0.0021 and P =

0.0349, respectively). There was no significant difference in allele frequency of telomerase mutations between the two subgroup control cohorts. One of the TERT gene mutations (c.3325G>A leading to an amino acid change at position p.G1109R) was found in six out of the 521 cirrhosis patients (four heterozygous mutations, two homozygous, allele frequency 0.008, Table 1) but in none of the control samples (0; P = 0.0072). The prevalence of telomerase gene mutations was not associated with a specific ethnicity of the patients (Supporting Fig. 3) or a specific etiology of cirrhosis (Table 2, Fig. 1). Aside from these gene

mutations, a number of single nucleotide polymorphisms and silent nucleotide CHIR-99021 cost mutations (not resulting in amino acid changes) were identified (Supporting Table 3). These gene variants were not present at different frequencies 上海皓元 in the cirrhosis group compared to the control

group. One example was the previously described c.58G>A variation in the TERC gene, which has previously been described to be associated with African ethnic origin28 and was also associated with African ethnic origin in our study. Together, these results indicated that telomerase gene mutation, but not polymorphic gene variants, were associated with the evolution of cirrhosis. The cirrhosis-associated TERC gene mutation (r.156C>A) was located in the pseudoknot domain and the second cirrhosis-associated TERC gene variant (c.244C>T) was located in the paired P5 region of the CR4/CR5 domain of the TERC gene, in close proximity to the recently identified r.323C>T mutation that was associated with bone marrow failure (Fig. 2A).29 Three cirrhosis-associated TERT gene mutations were located in Exon 1 (c.37C>A, c.40C>A, and c.193C>G) (Fig. 2B, Table 1, Supporting Fig. 1). Previous studies have shown that alterations at the N-terminus of TERT can affect the ability of TERT to maintain telomere length in cell culture models.30 The cirrhosis-associated c.37C>A and c.40C>A mutations have not previously been identified; the c.193C>G has been identified in a patient with acute myeloid leukemia.