Hereditary
optic neuropathies are diseases affecting the optic nerve. The most common are mitochondrial hereditary
optic neuropathies, i.e., the maternally inherited
Leber's hereditary optic neuropathy (LHON) and
dominant optic atrophy (DOA). They both share a mitochondrial pathogenesis that leads to the selective loss of retinal ganglion cells and axons, in particular of the papillo-macular bundle. Typically, LHON is characterized by an acute/subacute loss of central vision associated with impairment of color vision and swelling of
retinal nerve fibers followed by
optic atrophy. DOA, instead, is characterized by a childhood-onset and slowly progressive loss of central vision, worsening over the years, leading to
optic atrophy. The diagnostic workup includes neuro-ophthalmologic evaluation and genetic testing of the three most common
mitochondrial DNA mutations affecting complex I (11778/ND4, 3460/ND1, and 14484/ND6) for LHON and sequencing of the nuclear gene OPA1 for DOA. Therapeutic strategies are still limited including agents that bypass the complex I defect and exert an
antioxidant effect (
idebenone). Further strategies are aimed at stimulating compensatory mitochondrial biogenesis. Gene therapy is also a promising avenue that still needs to be validated.