Sex-specific genetic effects on susceptibility to idiopathic pulmonary fibrosis.

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic lung condition that is more prevalent in males than females. The reasons for this are not fully understood; differing environmental exposures due to historically sex-biased occupations and diagnostic bias are possible explanations. To date, over 20 independent genetic association signals have been reported for IPF susceptibility, but these have been discovered when combining males and females. The objectives of the present study were to assess whether there is a need to consider sex-specific effects when evaluating genetic risk in clinical prediction models for IPF and to test for sex-specific associations with IPF susceptibility.

Methods: We performed a genome-wide single nucleotide polymorphism (SNP)-by-sex interaction study meta-analysis of IPF risk in six independent case-control studies comprising 4561 cases (1280 females, 3281 males) and 22 888 controls (8360 females, 14 528 males) of European genetic ancestry. We used polygenic risk scores (PRSs) comprising common (minor allele frequency >1%) autosomal variants to assess differences in genetic risk prediction between males and females.

Results: The predictive accuracy of the PRSs were similar between males and females, regardless of whether using combined or sex-specific association results. Three new independent genetic association signals were identified (p<1×10^-6).

Conclusions: The predictive accuracy of common autosomal SNP-based PRSs did not vary significantly between males and females. We prioritised three genetic variants whose effect on IPF risk may be modified by sex. These findings would not account for the differences in prevalence between males and females. Future studies should ensure adequate representation of both sexes.