Marozkina, Nadzeya

Abstract Rationale Primary ciliary dyskinesia (PCD) pathogenic gene variants disrupt motile cilia, leading to both PCD and asthma through epithelial dysfunction. Asthma shows sex differences, and progesterone regulates ciliary beat frequency, indicating that genetic defects in ciliary proteins may exert sex-dependent effects. Therefore, we hypothesize that rare, pathogenic variants in PCD genes contribute to asthma risk in a sex-specific manner. Methods We performed a rare-variant aggregation analysis of the DNAH11 gene using UK Biobank OQFE exome dosages, with sex-stratified analyses. Within each sex, genotype dosages were coded as individual-level minor allele counts (0-2) and filtered to include variants with a minor allele frequency (MAF) ≤1% and a minor allele count (MAC) ≥5 across the cohort. Asthma phenotypes were defined from a curated dataset (N = 452,927), excluding COPD and other lung diseases. For each sex, logistic null models adjusted for age were fitted, and gene-level associations for binary outcomes were tested using SKAT, Burden, and SKAT-O. To assess variant-specific influences, we performed leave-one-out (LOO) analyses, sequentially omitting each variant and recalculating p-values. The effect size across the cohort was calculated by fitting a Firth logistic regression comparing carriers to non-carriers, adjusted for age by sex. Finally, sex modification was tested using a Firth model including carrier-by-sex interaction term. Results After filtering, DNAH11 included two rare variants; 7:21564185-G>T and 7:21591370-G>A in each sex (MAF≈1-2x10-5). Among females (N = 245,718; 28,649 with asthma), 16 carriers were observed (MAC≈16). Gene-based tests showed a significant association with asthma (Burden_p=0.004; SKAT-O_p=0.005; SKAT_p=0.013). Firth carrier model OR was 4.58 (95% CI 1.62-11.98, p = 0.0055) (Figure 1A). LOO analyses (Figure 1B) showed both variants contributed to the signal; removing 7:21591370-G>A increased SKAT-O p to 0.075 (Δ-log10p≈+1.15), while removing 7:21564185-G>T increased p to 0.014 (Δ-log10p≈+0.41, with the association remaining significant after removing the latter. Among males (N = 207,209; 20,777 with asthma), 10 carriers were observed (MAC≈10) with no significant association (Burden_p=0.926; SKAT-O_p=0.797; SKAT_p=0.668; Firth_p=0.781). The carrier-by-sex interaction term in the combined Firth model was not significant (p = 0.190), suggesting the female-specific signal could not be detected in the males due to limited power. Conclusions This analysis provides primary evidence that these rare, pathogenic variants in the DNAH11 PCD gene may contribute to asthma susceptibility in a sex-specific manner, with a significant association observed only in females. The signal was predominantly driven by 7:21591370-G>A. This suggests that genetic disruption of ciliary function may interact with female-specific hormonal factors (i.e., progesterone) to influence asthma risk. This abstract is funded by: NIH

Abstract Primary ciliary dyskinesia (PCD) results from mutations in over 50 genes that affect motile cilia (PMID: 29905515). PCD incidence is at least 1:7600 (PMID: 35051411). Asthma may be a PCD comorbidity (PMID: 36431268); and antigen stasis on the airway surface in PCD may predispose to asthma (PMID: 3831866). Methods. We analyzed the association between PCD and asthma in children ≤ 18 years old in two large electronic health record (EHR)-based databases: the Indiana Network for Patient Care Research (INPCR) cohort of 20 million EHRs and, in a validation cohort, TriNetX, with 112 million EHRs. We needed to address two issues. First, there is no ICD 10 code for PCD. Secondly, clinicians may confuse asthma and PCD in assessment. Therefore, we analyzed two diagnoses that, together, are unlikely to occur together in the absence of PCD: bronchiectasis (ICD10:J47) and situs inversus totalis (Q89.3) together (B-SIT). We asked whether subjects with B-SIT also had an asthma diagnosis ( ICD10 J45). We matched cases to controls, 1:3 in INPCR; and 1:1 in TriNetX, controlling for age, sex and race. We used conditional logistic regression adjusted for the matching strategy. For INPCR, we performed a conditional exact test: numbers were too small for adjusted models. This study was approved by the Indiana University and Case Western Reserve University IRBs. Results. In the initial INPCR study, 100% of children with B-SIT had an asthma diagnosis (p < 0.001). In the TriNetX validation cohort (Matched 1:1, n = 115 each), 84 children with B-SIT had asthma and 31 did not; in the controls, 12 had asthma and 103 did not (p = 2.2 x 10-16). The adjusted OR for B-SIT patients having asthma was 22.26 (95%CI: 10.80 – 45.91; p <0.001). Discussion. In two large EHR data sets, we found that most children with likely PCD (B-SIT) had a diagnosis of asthma. Local antigen stasis in PCD could contribute to the asthma phenotype in PCD, or perhaps even to asthma among patients heterozygous for PCD genes (PMID: 38457400). Additional studies are needed to understand the immunology, and this study is that it will need to be validated prospectively using airway reactivity testing after drug with-hold. In summary, children with PCD may need evaluation for airway reactivity. Further, providers should be alert to whether there are cardinal features of PCD among any of the children cared for with a diagnosis of asthma.

This case-control study uses electronic health record data to assess the association between primary ciliary dyskinesia and asthma in children.