From OMIMLHON presents in midlife as acute or subacute central vision loss leading to central scotoma and blindness. The disease has been associated with many missense mutations in the mtDNA that can act autonomously or in association with each other to cause the disease. The 18 allelic variants are MTND6*LDYT14459A (516006.0002); MTND4*LHON11778A (516003.0001); MTND1*LHON3460A (516000.0001); MTND6*LHON14484C (516006.0001); MTCYB*LHON15257A (516020.0001); MTCO3*LHON9438A (516050.0001); MTCO3*LHON9804A (516050.0002 ); MTND5*LHON13730A (516005.0002); MTND1*LHON4160C (516000.0002); MTND2*LHON5244A (516001.0002); MTCOI*LHON7444A (516030.0001); MTND1*LHON3394C (516000.0004); MTND5*LHON13708A (516005.0001); MTCYB*LHON15812A (516020.0002); MTND2*LHON4917G (516001.0001); MTND1*LHON4216C (516000.0003); MTND1*LHON4136G (516000.0002); MTATP6*LHON9101C (516060.0003); MTND4L*LHON10663C (516004.0002). The first 17 of these variants are summarized in Table M1, MIM12.
As pointed out by Riordan-Eva and Harding (1995), although the plethora of mtDNA mutations identified in families with LHON had resulted in confusion as to the pathogenic significance of each mutation, it had been established that the 3 primary mutations at basepairs 11778 (516003.0001), 3460 (516000.0001), and 14484 (516006.0001) are present in at least 90% of families. The correlation between the 14484 mutation and a good visual prognosis provides not only hope for affected patients, but also an approach for further research into the pathogenesis of LHON.
Yu-Wai-Man et al. (2009) provided a detailed review of LHON and autosomal dominant optic atrophy (OPA1; 165500), with emphasis on the selective vulnerability of retinal ganglion cells to mitochondrial dysfunction in both disorders.
http://www.omim.org/entry/535000 From MedlinePlus GeneticsLeber hereditary optic neuropathy (LHON) is an inherited form of vision loss. Although this condition usually begins in a person's teens or twenties, rare cases may appear in early childhood or later in adulthood. For unknown reasons, males are affected much more often than females.
Blurring and clouding of vision are usually the first symptoms of LHON. These vision problems may begin in one eye or simultaneously in both eyes; if vision loss starts in one eye, the other eye is usually affected within several weeks or months. Over time, vision in both eyes worsens with a severe loss of sharpness (visual acuity) and color vision. This condition mainly affects central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. Vision loss results from the death of cells in the nerve that relays visual information from the eyes to the brain (the optic nerve). Although central vision gradually improves in a small percentage of cases, in most cases the vision loss is profound and permanent.
Vision loss is typically the only symptom of LHON; however, some families with additional signs and symptoms have been reported. In these individuals, the condition is described as "LHON plus." In addition to vision loss, the features of LHON plus can include movement disorders, tremors, and abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects). Some affected individuals develop features similar to multiple sclerosis, which is a chronic disorder characterized by muscle weakness, poor coordination, numbness, and a variety of other health problems.
https://medlineplus.gov/genetics/condition/leber-hereditary-optic-neuropathy