Association between Genetic Polymorphisms of the Beta Adrenergic Receptor and Diurnal Intraocular Pressure in Chinese Volunteers and Glaucoma Patients.

Purpose: To evaluate the relationship between genetic polymorphisms of the beta adrenergic receptor (ADR) and diurnal intraocular pressure (IOP) in Chinese healthy volunteers, normal tension glaucoma (NTG) patients, and primary open-angle glaucoma (POAG) patients.

Methods: Fifty healthy volunteers (control group), 55 untreated NTG patients, and 55 untreated POAG patients were recruited. IOP of both eyes was measured at 3-hour intervals from 0600 to 2400 hours. For control group, IOP data from the eye with better mean deviation (MD) of visual field was used for statistical analysis. For glaucoma patients, IOP data from the eye with a greater visual field defect was used for statistical analysis. Genetic polymorphisms of ADR were determined by direct DNA sequencing. The relationship between IOP and genetic polymorphisms was statistically analyzed.

Results: R16G (A/G), L84L (G/A), and R175R (C/A) in β2-ADR showed significantly different allele in the three groups (p = 0.005, p = 0.045, and p = 0.045, respectively). For the POAG group, C/C of R389G (C/G) in β1-ADR had a significantly lower diurnal mean IOP (p < 0.001), peak IOP (p = 0.010), trough IOP (p < 0.001), and larger IOP range (p = 0.047) than G carriers; C/C of R389G (C/G) in β1-ADR and G carriers had parallel diurnal IOP curves but significantly different diurnal IOP levels (p = 0.001); C/C of Q27E (C/G) in β2-ADR had a significantly higher diurnal mean IOP (p = 0.045) than G carriers; G/G of L84L (G/A) in β2-ADR had a significantly higher diurnal mean IOP (p = 0.044) than A carriers; C/C of R175R (C/A) in β2-ADR had a significantly higher diurnal mean IOP (p = 0.044) than A carriers; T/T of W64R (T/C) in β3-ADR had a significantly smaller IOP range (p = 0.001) than C carriers.

Conclusion: Certain polymorphisms of β2-ADR showed significantly different genotype frequencies in healthy volunteers untreated NTG patients, and POAG patients. Polymorphisms of the β-ADR gene may alter the untreated IOP level of POAG patients.