The authors present a case report of 26 years old man with bilateral optic nerve 
neuropathy. Detection of heteroplasmic mutation of mitochondrial DNA at G3460A 
site confirmed the suspicion on Lebers hereditary optic nerve neuropathy (LHON). 
Genetic and environmental factors of the disease and various accompanying 
neurologic and other symptoms, which can together with the optic nerve defect 
participate in the development of of the LOHN clinical pattern are discussed. 
(Ref. 12.)