Heterozygous mutations in four telomere-related genes have been linked to pulmonary fibrosis, but little is known about similarities or differences of affected individuals. 115 patients with mutations in telomerase reverse transcriptase (TERT) (n=75), telomerase RNA component (TERC) (n=7), regulator of telomere elongation helicase 1 (RTEL1) (n=14) and poly(A)-specific ribonuclease (PARN) (n=19) were identified and clinical data were analysed. Approximately one-half (46%) had a multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF); others had unclassifiable lung fibrosis (20%), chronic hypersensitivity pneumonitis (12%), pleuroparenchymal fibroelastosis (10%), interstitial pneumonia with autoimmune features (7%), an idiopathic interstitial pneumonia (4%) and connective tissue disease-related interstitial fibrosis (3%). Discordant interstitial lung disease diagnoses were found in affected individuals from 80% of families. Patients with TERC mutations were diagnosed at an earlier age than those with PARN mutations (51±11 years versus 64±8 years; p=0.03) and had a higher incidence of haematological comorbidities. The mean rate of forced vital capacity decline was 300 mL·year−1 and the median time to death or transplant was 2.87 years. There was no significant difference in time to death or transplant for patients across gene mutation groups or for patients with a diagnosis of IPF versus a non-IPF diagnosis. Genetic mutations in telomere related genes lead to a variety of interstitial lung disease (ILD) diagnoses that are universally progressive.

SUMMARY Background Patients with hypersensitivity pneumonitis (HP) may develop lung fibrosis, which is associated with reduced survival. Families with pulmonary fibrosis can present with members diagnosed with idiopathic pulmonary fibrosis (IPF) or chronic HP (cHP), suggesting that fibrotic HP may share risk factors with IPF. Methods In an observational study of two independent cohorts of patients with cHP (UCSF n=145, UTSW n=72), we measured two common single nucleotide polymorphisms associated with IPF (MUC5B rs35705950 & TOLLIP rs5743890) and peripheral blood leukocyte telomere length and evaluated their associations with cHP disease, survival, and clinical-radiograph-pathologic features. Findings The frequency of the MUC5B minor allele, but not the TOLLIP minor allele, was significantly increased in cHP patients in both cohorts (UCSF MAF 24.4% & UTSW MAF 32.3%) compared to healthy controls (MAF 10.7%; p-values for comparison = <0.0001 for both cohorts) and similar to IPF (UCSF MAF 33.3% & UTSW MAF 32.0%, p-values for comparison=0.10 & 0.95, respectively). The MUC5B minor allele (adjusted OR 1.91, p=0.045) and shorter telomere length (adjusted OR 0.23, p=0.002) were associated with extent of radiographic fibrosis and other measures of lung remodeling and fibrosis in the combined cHP cohorts. Shorter telomere length had a significant association (adjusted HR 0.18, p=0.001) with reduced survival in the combined cHP cohorts. Interpretation The MUC5B promoter polymorphism rs35705950 and shorter telomere length are associated with extent of fibrosis in cHP. Shorter telomere length is associated with histopathology findings typical of usual interstitial pneumonia and reduced survival in cHP. Funding NIH grants KL2TR001870, T32HL098040, UL1TR001105, R01HL093096, and the Nina Ireland Program for Lung Health.

Background The utility of whole-exome sequencing (WES) for the diagnosis and management of adult-onset constitutional disorders has not been adequately studied. Genetic diagnostics may be advantageous in adults with chronic kidney disease (CKD), in whom the cause of kidney failure often remains unknown. Objective To study the diagnostic utility of WES in a selected referral population of adults with CKD. Design Observational cohort. Setting A major academic medical center. Patients 92 adults with CKD of unknown cause or familial nephropathy or hypertension. Measurements The diagnostic yield of WES and its potential effect on clinical management. Results Whole-exome sequencing provided a diagnosis in 22 of 92 patients (24%), including 9 probands with CKD of unknown cause and encompassing 13 distinct genetic disorders. Among these, loss-of-function mutations were identified in PARN in 2 probands diagnosed respectively with tubulointerstitial fibrosis and CKD of unknown cause. PARN mutations have been implicated in a short telomere syndrome characterized by lung, bone marrow, and liver fibrosis; these findings extend the phenotype of PARN mutations to renal fibrosis. In addition, review of the American College of Medical Genetics actionable genes identified a pathogenic BRCA2 mutation in a proband who was diagnosed with breast cancer on follow-up. The results affected clinical management in most identified cases, including initiation of targeted surveillance, familial screening to guide donor selection for transplantation, and changes in therapy. Limitation The small sample size and recruitment at a tertiary care academic center limit generalizability of findings among the broader CKD population. Conclusion Whole-exome sequencing identified diagnostic mutations in a substantial number of adults with CKD of many causes. Further study of the utility of WES in the evaluation and care of patients with CKD in additional settings is warranted. Primary Funding Source New York State Empire Clinical Research Investigator Program, Renal Research Institute, and National Human Genome Research Institute of the National Institutes of Health.

Leukocyte telomere length (LTL), MUC5B rs35705950, and TOLLIP rs5743890 have been associated with idiopathic pulmonary fibrosis (IPF). In this observational cohort study, we assessed the associations between these genomic markers and outcomes of survival and rate of disease progression in patients with interstitial pneumonia with autoimmune features (IPAF, n=250) and connective tissue disease-associated interstitial lung disease (CTD-ILD, n=248). IPF (n=499) was used as a comparator. LTL of IPAF and CTD-ILD patients (mean age-adjusted log-transformed T/S of −0.05, [SD 0.29] and −0.04 [0.25], respectively) are longer than IPF (−0.17 [0.32]). For IPAF, LTL <10th percentile is associated with faster lung function decline compared to LTL ≥10th percentile (−6.43%/year versus −0.86%/year, p<0.0001) and worse transplant-free survival (HR 2.97 [95% CI 1.70–5.20], p=0.00014). The MUC5B rs35705950 minor allele frequency is greater for IPAF (23.2 [95% CI 18.8–28.2], p<0.0001) than controls and is associated with worse transplant-free IPAF survival (HR 1.92, [95% CI 1.18–3.13], p=0.0091). Rheumatoid arthritis-associated ILD (RA-ILD) has shorter LTL than non-RA CTD-ILD (−0.14 [SD 0.27] versus −0.01 [0.23], p=0.00055) and higher MUC5B minor allele frequency (34.6 [95% CI 24.4–46.3] versus 14.1 [9.8–20.0], p=0.00025). Neither LTL nor MUC5B are associated with transplant-free CTD-ILD survival. LTL and MUC5B minor allele frequency have different associations with lung function progression and survival for IPAF and CTD-ILD.

Background Prior studies have shown that patients with pulmonary fibrosis with mutations in the telomerase genes have a high rate of certain complications after lung transplantation. However, few studies have investigated clinical outcomes by leukocyte telomere length. Methods We conducted an observational cohort study of all pulmonary fibrosis patients who underwent lung transplantation at a single center between January 1, 2007 and December 31, 2014. Leukocyte telomere length was measured from a sample of blood collected prior to lung transplantation and subjects were stratified into two groups (telomere length <10th versus ≥10th percentile). The primary outcome was post-lung transplant survival. Secondary outcomes included incidence of allograft dysfunction, non-pulmonary organ dysfunction and infection. Results Approximately one-third (32%) of subjects had a telomere length below the 10th percentile. Telomere length <10th percentile was independently associated with worse survival (HR 10.9, 95% CI 2.7–44.8, p=0.001). Telomere length <10th percentile was also independently associated with a shorter time to the onset of chronic lung allograft dysfunction (CLAD) (HR 6.3, 95% CI 2.0–20.0, p=0.002). Grade 3 primary graft dysfunction occurred more frequently in the <10th percentile group compared to the ≥10th percentile group (28% vs 7%, p=0.034). There was no difference in the incidence of acute cellular rejection, cytopenias, infection or renal dysfunction in the two groups. Conclusions Telomere length <10th percentile was associated with worse survival and shorter time to onset of CLAD, and thus represents a biomarker that may aid in the risk stratification of pulmonary fibrosis patients prior to lung transplantation.