Test Details: Leber Hereditary Optic Neuropathy (LHON), is a maternally inherited disorder resulting in optic nerve degeneration and dysrhythmia. Five mitochondrial point mutations in the gene coding subunits ND1, ND4 and ND6 of NADH-CoQ oxidoreductase have been associated with diagnosis of the disease. The age of onset and the clinical course for disease caused by mitochondrial mutation are variable due to mitochondrial heteroplasmy i.e. concurrent presence of wild type and mutant mitochondria in tissues and cells. Indication for testing are individuals with painless bilateral loss of vision and familial history of the vision related problems in the maternal lineage.