Hereditary Optic Neuropathy Essay

Leber’s Hereditary Optic Neuropathy (LHON) is a kind of genetic disorder that caused by the pathogenic variants in mtDNA (mitochondrial DNA) leading to a bilateral visual loss during young adult life, especially in males. Mitochondrial DNA is found in mitochondria which breakdowns carbohydrates and fatty acids to generate energy so that the body cells can use. Mitochondrial DNA is inherited maternally, it is because the paternal mitochondria in sperm have disappeared during the early embryogenesis. (Sato, M. & Sato, K., 2013) LHON has an inheritance pattern of mtDNA which is maternal inheritance. The genetic disorder of LHON can affect both males and females in every generation of a family. If the mother is the carrier or affected by the mtDNA
And, some of the individuals who develop the features of LHON does not have the family history of this disease. Environmental factors such as alcohol and smoking will trigger of vision loss especially in those genetically more susceptible to LHON. (McClelland, C., Meyerson, C. & Van Stavern, G., 2015. ) LHON is happened because of the point mutation in one of three mitochondrial DNA (mtDNA), which are G3460A, G11778A, and T14484C in the NADH dehydrogenase genes that coding for the ND1, ND4, and ND6 subunits of complex I of the mitochondrial respiratory chain. (Mackey et al., 1996) The most common LHON mutation is the G11778A mutation which accounting for about 70% of all LHON cases, (Newman NJ, 2005) then, follow by the T14484C or G3460A mutation, and about 10% are other rare mutations. These three mtDNA nucleotide variants are primary LHON mutation as each of them has connection with the optic nerve injury even when occurring in isolation. (Abu-Amero, K.K., 2011) The secondary LHON mutation remains unclear and the information that is known for now is that the secondary LHON mutations will not cause LHON in