HeterozygousRTEL1mutations are associated with familial pulmonary fibrosis

Abstract

Pulmonary fibrosis is a fatal disease with progressive loss of respiratory function. Defective telomere maintenance leading to telomere shortening is a cause of pulmonary fibrosis, as mutations in the telomerase component genesTERT(reverse transcriptase) andTERC(RNA component) are found in 15% of familial pulmonary fibrosis (FPF) cases. However, so far, about 85% of FPF remain genetically uncharacterised.Here, in order to identify new genetic causes of FPF, we performed whole-exome sequencing, with a candidate-gene approach, of 47 affected subjects from 35 families with FPF withoutTERTandTERCmutations.We identified heterozygous mutations in regulator of telomere elongation helicase 1 (RTEL1) in four families. RTEL1 is a DNA helicase with roles in DNA replication, genome stability, DNA repair and telomere maintenance. The heterozygousRTEL1mutations segregated as an autosomal dominant trait in FPF, and were predicted by structural analyses to severely affect the function and/or stability of RTEL1. In agreement with this,RTEL1-mutated patients exhibited short telomeres in comparison with age-matched controls.Our results provide evidence that heterozygousRTEL1mutations are responsible for FPF and, thereby, extend the clinical spectrum of RTEL1 deficiency. Thus,RTEL1enlarges the number of telomere-associated genes implicated in FPF.