Genetic Features and Clinical Heterogeneity of Leber Hereditary Optic Neuropathy in Adolescent and Adult Patients: A Case Series on Arab Patients.

Leber hereditary optic neuropathy (LHON) is a rare disorder characterized by painless progressive visual loss. LHON is caused by maternally inherited mitochondrial DNA (mtDNA) point mutations, impairing the electron transport chain and oxidative phosphorylation. Environmental and nuclear factors may further influence disease manifestation. This case series describes the clinical characteristics, mutation profiles, and visual outcomes in patients from Saudi Arabia and Yemen, regions where reported data remain scarce. Patients were diagnosed with LHON based on characteristic clinical features confirmed through genetic testing. The series highlights both adolescent-and adult-disease onset, with most patients carrying the m.11778G>A mutation, consistent with global prevalence patterns. Distinct modifiable risk factors were identified in several cases. Treatment with Idebenone (two out of two patients) was associated with visual improvement and favorable outcomes, while patients treated with coenzyme Q10 reported subjective visual improvement that was not detected through visual assessments. These findings contribute to the limited data on LHON in the Arabian Peninsula underscoring the importance of early genetic testing and treatment initiation. However, the small sample size, non-uniform participant visit schedules, and variable follow-up period limit the generalizability of the findings. Increased regional awareness and reporting, as well as mitigating financial obstacles, are essential to improve diagnostic timing and optimize outcomes in this rare but impactful disorder.