Interstitial lung diseases associated with mutations of poly(A)-specific ribonuclease: A multicentre retrospective study

Abstract

Background and objective: Poly(A)-specific ribonuclease (PARN) mutations have been associated with familial pulmonary fibrosis. This study aims to describe the phenotype of patients with interstitial lung disease (ILD) and heterozygous PARN mutations.

Methods: We performed a retrospective, observational, non-interventional study of patients with an ILD diagnosis and a pathogenic heterozygous PARN mutation followed up in a centre of the OrphaLung network.

Results: We included 31 patients (29 from 16 kindreds and two sporadic patients). The median age at ILD diagnosis was 59 years (range 54 to 63). In total, 23 (74%) patients had a smoking history and/or fibrogenic exposure. The pulmonary phenotypes were heterogenous, but the most frequent diagnosis was idiopathic pulmonary fibrosis (n = 12, 39%). Haematological abnormalities were identified in three patients and liver disease in two. In total, 21 patients received a specific treatment for ILD: steroids (n = 13), antifibrotic agents (n = 11), immunosuppressants (n = 5) and N-acetyl cysteine (n = 2). The median forced vital capacity decline for the whole sample was 256 ml/year (range -363 to -148). After a median follow-up of 32 months (range 18 to 66), 10 patients had died and six had undergone lung transplantation. The median transplantation-free survival was 54 months (95% CI 29 to ∞). Extra-pulmonary features were less frequent with PARN mutation than telomerase reverse transcriptase (TERT) or telomerase RNA component (TERC) mutation.

Conclusion: IPF is common among individuals with PARN mutation, but other ILD subtypes may be observed.

Keywords: PARN; idiopathic interstitial pneumonia; idiopathic pulmonary fibrosis; interstitial lung disease; mutation; poly(A)-specific ribonuclease; telomere homeostasis; variant.