Abstract
Leber hereditary optic neuropathy (LHON) is maternally inherited disorder characterized by subacute loss of vision due to impairment of retinal ganglion cells eventually leading to optic atrophy. Three prevalent point mutations in mitochondrial DNA: m.11778G>A, m.3460G>A, and m.14484T>C, are causative in the majority (95%) of cases.
All of these mutations affect one of the subunits of complex I, NADH-ubiquinone oxidoreductase, the first enzyme of the mitochondrial respiratory chain. The presence of a mutation is necessary but not sufficient to cause visual loss.
The penetrance is incomplete with only about 50% of men and 10% of women event. developing clinical signs of the disease. Recently, it was proven that early initiation of therapy with idebenone in patients manifesting LHON ameliorates visual functions and clinical trials testing several other promising therapies are underway.
Incomplete penetrance, similarites with other disorders affecting the optic nerve and a great variability of clinical features cause considerable diagnostic difficulties. Often there is a delay in therapy initiation, as late as in the phase of the irreversible optic nerve damage.
In 2013, we established a multidisciplinary medical care centre dedicated to patients with mitochondrial optic neuropathies in General University Hospital in Prague to develop effective diagnostic and treatment algorithms and to study the underlying pathogenetic mechanisms.