Leber hereditary optic neuropathy (LHON), also known as Leber optic atrophy, is an inherited optic nerve disease caused by genetic mutations in the mitochondria. It is the most common inherited mitochondrial disorder and classically affects young males. It presents as a unilateral, progressive optic neuropathy that eventually becomes bilateral after months to years.

Age of onset is between 10 and 30 years, but a late-onset disease has been reported with a few cases occurring around the age of 70 years. Male individuals are more affected than female individuals.

Patients typically present with a unilateral, slowly progressive vision loss. The vision loss is painless and initially can be described as loss of color saturation or clouding. Eventually, the vision loss will become bilateral after weeks, months, or even years. Most commonly, the disease becomes bilateral after months.

Over 95% of LHON patients have 1 of 3 mitochondrial DNA point mutations: G11778A, T14484C, and G3460A. Of these, G11778A is the most common and associated with severe disease. T14484C mutation is associated with the best prognosis with a chance of spontaneous visual recovery. G3460A mutation has the worst prognosis.

Individuals at risk are direct offspring of affected mothers. Male patients are affected 80% of the time, although the exact reason is unknown. No environmental factors have been associated with the disease in young men and boys. However, in late-onset LHON, alcohol and tobacco use have been shown to advance the disease.

LHON is a disease that only affects the eyes, but it can be associated with other systemic conditions. This is called LHON plus disease and typically will include neurologic or cardiac features. These can include tremors, dystonia, myopathy, arrhythmias, and cardiac conduction defects.