Phenotypic Expressions of Chronic Leber's Hereditary Optic Neuropathy Patients with Primary and Secondary Mitochondrial Mutations Presenting at Tertiary Eye Care Center, South India

Abstract

Aim: The aim was to report the phenotypic expression of chronic Leber's hereditary optic neuropathy (LHON) patients with primary and secondary mitochondrial mutations presenting at a tertiary eye care center in South India. Materials and Methods: Of 51 patients suspected to have LHON, 15 patients turned out to be positive for mitochondrial mutations. All 15 patients with LHON are in the chronic phase of the disease and have undergone clinical examination that included visual acuity, fundus examination, visual fields, and optical coherence tomography. Clinical data were compared among the LHON patients with primary mutations of G11778A and T14484C and grouped secondary mutations. Descriptive analysis was reported. Results: There was no significant difference found in visual acuities in both the eyes of the three genotypic groups (G11778A, T14484C, and secondary mutations) (P > 0.05). Retinal nerve fiber layer (RNFL) analysis showed that nine patients carrying G11778A and three patients carrying secondary mutations were similar, while two patients with T14484C showed severe thinning of RNFL in all four quadrants. Conclusions: Among a small percentage of patients who were positive for LHON mutations, severe RNFL thinning was the most prominent finding in the T14484C mutation that differentiates from G11778A and secondary mutations. Other clinical features seem to be similar among all genotypic groups examined.