Association of the ACE2 rs879922 Polymorphism with Glaucoma Risk and Serum ACE2 Levels

Background/Objectives: Glaucoma is a progressive optic neuropathy and one of the leading causes of irreversible blindness worldwide. Despite the important role of elevated intraocular pressure in disease development, genetic factors such as polymorphisms in the angiotensin-converting enzyme 2 (ACE2) gene may contribute to disease susceptibility. This study aims to evaluate the correlation between the rs879922 polymorphism in the ACE2 gene and glaucoma risk, as well as to assess its relationship with serum ACE2 protein levels. Methods: Patients diagnosed with glaucoma and healthy individuals were enrolled in this study. The rs879922 polymorphism was tested using the PCR-RFLP method. Serum ACE2 concentrations were measured using the ELISA method and expressed as mean ± standard deviation. Results: The rs879922 polymorphism was significantly associated with glaucoma in the allelic (OR = 2.04, p = 0.01) and recessive (OR = 2.63, p = 0.01) models, but not in the dominant model (OR = 1.80, p = 0.21). Genotype distributions deviated from Hardy–Weinberg equilibrium in both groups. Mean serum ACE2 levels were higher in glaucoma patients in comparison to controls (5.23 vs. 3.29 ng/mL). Genotype-stratified analysis revealed that in controls, the GG genotype was associated with the highest ACE2 levels, whereas in glaucoma patients, the CC genotype showed the highest concentrations. Conclusions: The rs879922 polymorphism in the ACE2 gene may be associated with glaucoma susceptibility and influences serum ACE2 levels. The relationship between genotype and ACE2 concentration appears to differ between glaucoma patients and healthy individuals, suggesting a potential interaction between genetic variation and disease status.