Abstract
Abstract: :
Purpose: OPA1, the gene responsible for autosomal dominant optic atrophy, was recently found to be strongly associated with normal tension glaucoma (NTG). About a fifth of NTG patients had double polymorphisms on intervening sequence (IVS) 8 of the OPA1 gene (genotype IVS 8 +4 C/T; +32 T/C), compared to 4% of controls. The aim of this study was to compare the presenting clinical features of NTG patients with and without such polymorphisms. Methods: This was a retrospective analysis of 108 NTG patients who had been genotyped for OPA1 variations, and who had previously undergone automated perimetry and Heidelberg retina tomography (HRT). Only one eye from each patient was included. The following were analysed: sex, age at diagnosis, family history of glaucoma, history of ischemic risk factors and vasospasm, laterality of glaucoma, presenting and highest diurnal intraocular pressure (IOP), initial cup-disc (CD) ratio, mean deviation (MD) and corrected pattern standard deviation (CPSD) of baseline visual fields, and optic disc size and initial neuroretinal-rim area as measured by HRT. Results: There were 25 NTG patients (Group 1) with the at-risk OPA1 genotype IVS 8 +4 C/T; +32 T/C, and 83 NTG patients (Group 2) without this genotype. There was no significant difference in the 2 groups with respect to sex, age at diagnosis, family history of glaucoma, history of ischemic risk factors and vasospasm or laterality of glaucoma. The mean presenting and highest diurnal IOP (mmHg), initial CD ratio, and MD (dB) and CPSD (dB) of baseline visual fields were 16.2, 17.9, 0.75, -8.7, and 8.5 in group 1 and 17.0, 18.9, 0.76, -8.0, and 8.0 in group 2 respectively (All P values ≷.05). The mean HRT parameters, disc size (mm) and global, temporal, temporal superior, temporal inferior, nasal, nasal superior, and nasal inferior neuroretinal-rim areas (mm2) were 2.04, 0.904, 0.129, 0.098, 0.102, 0.289, 0.131, and 0.156 in group 1, and 2.11, 0.892, 0.137, 0.100, 0.082, 0.301, 0.138, and 0.134 in group 2 respectively (All P values ≷.05). Conclusion: The results suggest a lack of phenotypic differences in normal tension glaucoma patients with and without the OPA1 polymorphisms IVS 8 +4 C/T; +32 T/C.
Keywords: 420 genetics • 498 optic disc • 355 clinical (human) or epidemiologic studies: risk factor assessment