PARN mutation linked to interstitial lung disease

Individuals with poly(A)-specific ribonuclease (PARN) mutation are likely to have idiopathic pulmonary fibrosis (IPF), but other interstitial lung disease (ILD) subtypes may also occur, according to a study.

The authors conducted a retrospective, observational, noninterventional study to characterize the phenotype of patients with ILD and heterozygous PARN mutations. Patients with an ILD diagnosis and a pathogenic heterozygous PARN mutation who were followed-up in a centre of the OrphaLung Network were included in the analysis.

Thirty-one patients met the eligibility criteria (29 from 16 kindreds and two sporadic patients). The median age at ILD diagnosis was 59 years (range 54‒63). Twenty-three patients (74 percent) had a smoking history or fibrogenic exposure.

Pulmonary phenotypes were heterogenous, but IPF was the most common diagnosis (n=12, 39 percent). Three patients were found to have haematological abnormalities, while two had liver disease.

Of the participants, 21 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 entire cohort was 256 ml/year (range ‒363 to ‒148).

Ten patients had died and six had undergone lung transplantation after a median follow-up of 32 months (range 18‒66). The median transplantation-free survival was 54 months (95 percent confidence interval, 29 to ∞).

Furthermore, extrapulmonary features were less frequent with PARN mutation compared with telomerase reverse transcriptase (TERT) or telomerase RNA component (TERC) mutation.

“PARN mutations have been associated with familial pulmonary fibrosis,” the authors said.