Leber hereditary optic neuropathy (LHON) is caused by mitochondrial DNA point mutations. Which of the following is the most common primary mutation?

• A m.3460G>A in MT-ND1
• B m.14484T>C in MT-ND6
• C m.3243A>G in MT-TL1
• D m.11778G>A in MT-ND4 ✓

Explanation

The m.11778G>A mutation in MT-ND4 (NADH dehydrogenase subunit 4) accounts for approximately 70% of LHON cases worldwide, producing the worst prognosis with least spontaneous visual recovery. m.3460G>A (MT-ND1, ~13%) and m.14484T>C (MT-ND6, ~14%) are the other primary mutations. The m.3243A>G mutation causes MELAS syndrome, not LHON. Idebenone is the only approved treatment for LHON and is most effective in the acute/subacute phase.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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