What causes Leber hereditary optic neuropathy ?
What causes Leber hereditary optic neuropathy (LHON)? Leber hereditary optic neuropathy is a condition related to changes in mitochondrial DNA. Mutations in the MT-ND1, MT-ND4, MT-ND4L, and MT-ND6 genes cause LHON. These genes are contained in mitochondrial DNA. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA (known as mitochondrial DNA or mtDNA). The genes related to Leber hereditary optic neuropathy each provide instructions for making a protein involved in normal mitochondrial function. These proteins are part of a large enzyme complex in mitochondria that helps convert oxygen and simple sugars to energy. Mutations in any of the genes disrupt this process. It remains unclear how these genetic changes cause the death of cells in the optic nerve and lead to the specific features of Leber hereditary optic neuropathy. Click here to visit the Genetic Home Reference Web site to learn more about how mutations in these genes cause Leber hereditary optic neuropathy.