Which optic nerve condition is inherited through maternal mitochondrial DNA mutations?

Which optic nerve condition is inherited through maternal mitochondrial DNA mutations?

• A. Dominant optic atrophy
• B. Leber's optic neuropathy
• C. Optic nerve hypoplasia
• D. NAION

Answer: (B)

Leber's hereditary optic neuropathy is inherited through maternal mitochondrial DNA mutations. Mitochondrial DNA is passed from the mother to all her offspring, so diseases caused by mtDNA mutations show maternal inheritance. In LHON, mutations in mitochondrial genes encoding subunits of Complex I (most commonly ND4, ND1, or ND6) impair oxidative phosphorylation in retinal ganglion cells, making the optic nerve particularly susceptible to dysfunction. Clinically, it typically starts with subacute, painless central vision loss in one eye, with the other eye often following within weeks to months. Penetrance is incomplete and higher in males, with smoking increasing risk. The other options involve autosomal dominant inheritance (dominant optic atrophy), developmental malformation (optic nerve hypoplasia), or non-arteritic ischemic processes (NAION), none of which are due to maternal mtDNA mutations.

Leber's hereditary optic neuropathy is inherited through maternal mitochondrial DNA mutations. Mitochondrial DNA is passed from the mother to all her offspring, so diseases caused by mtDNA mutations show maternal inheritance. In LHON, mutations in mitochondrial genes encoding subunits of Complex I (most commonly ND4, ND1, or ND6) impair oxidative phosphorylation in retinal ganglion cells, making the optic nerve particularly susceptible to dysfunction. Clinically, it typically starts with subacute, painless central vision loss in one eye, with the other eye often following within weeks to months. Penetrance is incomplete and higher in males, with smoking increasing risk. The other options involve autosomal dominant inheritance (dominant optic atrophy), developmental malformation (optic nerve hypoplasia), or non-arteritic ischemic processes (NAION), none of which are due to maternal mtDNA mutations.