Genomic insights into somatic mutations from occupational exposure to low-dose ionizing radiation

OBJECTIVE: Low-dose ionizing radiation (LDIR, ≤100 mGy) is a public health concern due to its extensive use in diagnostic and therapeutic imaging. This study examined somatic variants (SV) among Korean industrial radiographers exposed to LDIR using whole-genome sequencing (WGS). METHODS: WGS data from 65 workers (mean age 36.7 years) collected between 2016 and 2023 were analyzed. Participants had a mean employment duration of 12.7 years and an average cumulative radiation dose of 33.9 mSv from National Dose Registry records. SV were identified via the GATK Mutect2 single-sample workflow applied to peripheral blood-derived DNA and sequentially filtered using standard pipelines, including FilterMutectCalls, population frequency, recurrent artifacts, Funcotator annotation, and manual Integrative Genomics Viewer review. RESULTS: A total of 105 170 somatic variants were identified, with a median of 1744 variants per individual, approximately 98% of which were single nucleotide variants. Cumulative radiation dose showed a significant positive correlation with total SV burden (R=0.32, P=0.013), including both coding (R=0.34, P=0.008) and non-coding regions (R=0.31, P=0.015). Age, smoking, alcohol consumption, hypertension, and hyperlipidemia were not significantly associated with variant burden. CONCLUSIONS: These WGS-based findings provide preliminary insight into blood-derived SV patterns among occupationally exposed radiation workers. Given the small sample size, blood-only design, and absence of matched unexposed controls, the findings should be interpreted as hypothesis-generating and require validation in larger longitudinal studies with comprehensive exposure assessment.