Previous studies have identified subclinical lung disease in family members of probands with familial pulmonary fibrosis, but the natural history of preclinical pulmonary fibrosis is uncertain. The purpose of this study was to determine whether individuals with preclinical lung disease will develop pulmonary fibrosis. After a 27-year interval, two subjects with manifestations of preclinical familial pulmonary fibrosis, including asymptomatic alveolar inflammation and alveolar macrophage activation, were reevaluated for lung disease. CT scans of the chest, pulmonary function tests, and BAL were performed, and genomic DNA was analyzed for mutations in candidate genes associated with familial pulmonary fibrosis. One subject developed symptomatic familial pulmonary fibrosis and was treated with oxygen; her sister remained asymptomatic but had findings of pulmonary fibrosis on high-resolution CT scan of the chest. High concentrations of lymphocytes were found in BAL fluid from both subjects. Genetic sequencing and analyses identified a novel heterozygous mutation in telomerase reverse transcriptase (TERT, R1084P), resulting in telomerase dysfunction and short telomeres in both subjects. In familial pulmonary fibrosis, asymptomatic preclinical alveolar inflammation associated with mutation in TERT and telomerase insufficiency can progress to fibrotic lung disease over 2 to 3 decades.
Trial registry: ClinicalTrials.gov; No.: NCT00071045; URL: www.clinicaltrials.gov.