Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Leber hereditary optic neuropathy ?
    ### Response:
    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.
    