Genomic structural equation modeling identifies shared genetic architecture and novel loci for halitosis

The intricate shared genetic architecture underlying halitosis and its related disorders-including salivary secretion disorders, chronic periodontitis, gastroesophageal reflux disease, dental caries, chronic sinusitis, helicobacter pylori infection, and porphyromonas genus abundance-remains incompletely characterized. Our study employed genomic structural equation modeling (Genomic SEM) to define the halitosis common factor (HCF) representing the shared genetic architecture of halitosis-related disorders. Coupled with diverse post-GWAS analytical methods, we aimed to discover susceptible loci and investigate genetic associations with external traits. Furthermore, we explored enriched genetic pathways, cellular layers, and genomic elements. Polygenic risk score analyses, leveraging our integrated GWAS data, were conducted to assess chromosomal-level risk associations for the HCF. A well-fitted genomic SEM integrated GWAS data, revealing the shared genetic architecture of halitosis-related disorders. We identified 23 independent genome-wide significant SNP loci, all previously unreported for this HCF relative to the input single-trait GWAS. Fine-mapping of variants and gene prioritization pinpointed numerous high-confidence putative causal variants and candidate susceptible genes. Subsequent analyses further illuminated the shared genetic architecture underlying HCF and multiple external traits, notably neuropsychiatric characteristics, cognitive function, and inflammatory or metabolic conditions. Notably, this study presents the first comprehensive genetic characterization of halitosis and its related disorders through a GWAS analysis of an unmeasured composite phenotype, providing novel insights into shared etiological pathways potentially linking oral health to systemic factors across these conditions.