A 45-year-old man presents with painless progressive bilateral disc pallor over 6 months. There is centrocaecal scotoma in both eyes on Humphrey visual field analysis. He denies tobacco or alcohol use and is not on any medications. Mitochondrial DNA analysis reveals an 11778 G→A point mutation. The diagnosis is:
- A Neuromyelitis optica (NMO) with bilateral optic neuritis
- B Leber's hereditary optic neuropathy (LHON) ✓
- C Dominant optic atrophy (Kjer's disease)
- D Compressive optic neuropathy from meningioma
Explanation
Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disorder caused by point mutations in mtDNA; the most common is the m.11778G>A mutation in the ND4 subunit gene (accounting for 50–70% of cases), followed by m.3460G>A (ND1) and m.14484T>C (ND6). It affects primarily young men (maternal inheritance from mother to all offspring, but males preferentially affected due to modifying X-chromosomal and environmental factors) with acute or subacute bilateral sequential central visual loss and centrocaecal scotoma. Idebenone is the only approved treatment, showing partial visual recovery especially with the m.14484T>C mutation.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.