Background:Idiopathic pulmonary fibrosis (IPF) is an age-related and progressive interstitial lung disease.Up to 20％ of cases of IPF cluster in families,genetic factors contribute significantly to the pathogenesis of the disease.This study aimed to explore the association between rare genetic variants and IPF in Chinese Han families.Methods:A Han family,comprising three IPF patients and five unaffected their first-degree relatives,and 100 ethnically matched control individuals from North China were enrolled in this study.Peripheral blood was collected,and genomic DNA was extracted.To elucidate if rare genetic variants are associated with the familial IPF,we performed whole-exome sequencing of affected members from a Chinese Han IPF family.Candidate rare variants were then confirmed by Sanger sequencing.Results:We identified a potentially damaging rare variant-a heterozygous mutation c.2146G＞A in exon 6 of the gene encoding for telomerase reverse transcriptase (TERT),which results in an amino acid substitution (p.Ala716Thr).We confirmed the missense mutation by Sanger sequencing in all the affected family members but did not detect this mutation in 100 ethnically matched healthy controls.Patients carried this mutation were characterized by the frequently acute exacerbation of IPF phenotype,with poor prognosis.The mean time to death was 2.8 years after diagnosis.Conclusion:Using next-generation sequencing technology in familial IPF patients,we identified the heterozygous rare variant in TERT gene,and strengthened the importance of genetic variants in telomere-related pathogenesis in Chinese IPF patients.