Clinical Profile of Patients with Leber Hereditary Optic Neuropathy (LHON): An Ambispective Study of North Indian Cohorts

Background: Leber hereditary optic neuropathy (LHON) is a maternally inherited disease resulting in irreversible visual loss usually in patients belonging to the age group of 15-35 years. Clinically, the patients present with sequential or bilateral, painless, progressive visual loss with central (or ceco-central) scotomas. Although the three mutations, namely, G11778A, T14484C, and G3460A contribute to >95% of LHON cases globally, the relative frequency of each mutation varies. Aims and Objectives: We aimed to assess the clinical and genetic profile of patients with mutation-positive LHON at a north Indian tertiary care center. Materials and Methodology: One hundred sixty-one patients (61 prospective and 100 retrospective) presenting with the clinical diagnosis of LHON were screened for the three known mitochondrial mutations (G1178A, G3460A, T14448C). Patients were assessed for detailed clinical, ophthalmological, and neurological examinations. Five milliliter of blood sample was taken to assess the three known mutations using DNA isolation and Sanger sequencing. Results and Discussion: Clinical profile of 83 patients with both positive and negative mutations was analyzed. Twenty-three out of 161 patients (14.3%) tested positive for either of the three mutations. The majority of the patients harbored G11778A mutation (56.52%) followed by T14484C (34.78%) and G3460A (8.69%). No statistical difference could be noted between the clinical profiles of mutation-negative and -positive patients.