Examination of host genetic effects on nasal microbiome composition

Background: Genetic predisposition increases risk for asthma, and distinct nasal microbial compositions are associated with asthma. Host genetics might shape nasal microbiome composition. Objective: We examined associations between host genetics and nasal microbiome composition. Methods: Nasal samples were collected from 584 participants from the Mount Sinai Health System, New York. Seventy-seven follow-up samples were collected from a subset of 40 participants. 16S rRNA sequencing and RNA sequencing were performed on nasal samples. Beta diversity was calculated, variant calling on RNA sequencing data was performed, and genetic relatedness between individuals was determined. Using linear regression models, we tested for associations between genetic relatedness and nasal microbiome composition. Results: The median age of the cohort was 14.6 (interquartile range 11.2-19.5) years, with participants representing diverse ancestries and 52.7% of the cohort being female. For participants who provided follow-up samples, the median time between samples was 5.1 (interquartile range 1.4-7.2) months. Nasal microbiome composition similarity as reflected by beta diversity was significantly higher within subjects over time versus between subjects (coefficient = 0.091, P = 2.84⁻⁷). There was no significant association between genetic relatedness and beta diversity (coefficient = −0.05, P = .29). Additional analyses exploring the relationship between beta diversity and genetic variance yielded similar results. Conclusion: Host genetics has little influence on nasal microbiome composition.