The Association of G Protein-Coupled Estrogen Receptor (GPER) Polymorphisms with Ionizing Radiation Exposure in Healthcare Workers

Background/Objectives: The G protein-coupled estrogen receptor (GPER) is known to interact with cellular stress responses and DNA damage pathways. Therefore, exposure to ionizing radiation may modulate the biological consequences of single-nucleotide polymorphisms in the GPR30 gene. This study aims to evaluate the association between GPER polymorphisms and radiation sensitivity. Methods: The study included 50 healthcare workers exposed to ionizing radiation and 36 healthy individuals with no known occupational exposure to radiation. Genomic DNA was isolated and PCR products were purified using GeneAll kits. Genomic regions encompassing three GPER single-nucleotide polymorphisms (rs3808350, rs3808351, and rs11544331) were amplified by polymerase chain reaction (PCR), followed by DNA sequencing analysis using the BigDye Cycle Sequencing Kit. In addition, an in silico functional and clinical annotation of rs11544331 was performed using Ensembl VEP, SIFT, PolyPhen-2, AlphaMissense, CADD, UniProt, and ClinVar. Results: Genotypic, dominant, and allelic analyses revealed no significant association between radiation exposure and the rs3808350 or rs3808351 polymorphisms. In contrast, a statistically significant association was observed for rs11544331. The frequency of individuals carrying the CT and TT genotypes (CT + TT) was significantly higher in the ionizing radiation-exposed group compared with the control group (OR = 2.981; 95% CI: 1.106–7.904; p = 0.0241). In allelic analysis, the T allele was more prevalent in the exposed group and was significantly associated with radiation exposure (OR = 2.959; 95% CI: 1.282–6.606; p = 0.0110). In silico analysis confirmed that rs11544331 corresponds to the p.Pro16Leu substitution in GPER1; however, SIFT, PolyPhen-2, AlphaMissense, CADD, and ClinVar consistently indicated a tolerated, benign, likely benign, or low-deleteriousness profile. Conclusions: GPER-mediated stress responses and genetic polymorphisms may play a potential role in determining genetic susceptibility following exposure to ionizing radiation.