Genetic variations interact with polybrominated diphenyl ether exposure to alter lipid homeostasis

Polybrominated diphenyl ethers (PBDEs) are implicated in dyslipidemia, but the molecular basis of individual susceptibility remains elusive. Here we report an analysis based on the China National Human Biomonitoring cohort, where we integrate exposome, genomic, and metabolomic data to identify 3,571 genetic variants that interact with PBDE exposure to influence dyslipidemia risk. Metabolomic analysis highlights glycine and glycerophosphate as key mediators. A polygenic risk score derived from these PBDE-interactive variants significantly enhances dyslipidemia prediction in highly exposed individuals. Among these, rs9869609 emerges as a candidate causal variant, showing the strongest association with hypercholesterolemia risk (β = 1.18, FDR = 0.0078). Further functional validation using single-base CRISPR/Cas9 editing reveals that the rs9869609-G allele downregulates SLC6A20 expression by strengthening BHLHE40 binding, which further impairs glycine transport and promotes cholesterol accumulation, particularly under 2,2',4,4'-Tetrabromodiphenyl ether exposure. Collectively, our study elucidates a gene-environment interaction mechanism through which genetic variants modulate lipid metabolism in response to PBDE exposure.