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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Leber hereditary optic neuropathy


Other Names for this Disease
  • Leber optic atrophy
  • Leber’s disease
  • LHON
  • Optic atrophy, Leber type
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Overview



What is Leber hereditary optic neuropathy (LHON)?

What are the signs and symptoms of Leber hereditary optic neuropathy (LHON)?

What causes Leber hereditary optic neuropathy (LHON)?

How is Leber hereditary optic neuropathy (LHON) inherited?


What is Leber hereditary optic neuropathy (LHON)?

Leber 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. This condition is caused by mutations in the MT-ND1, MT-ND4, MT-ND4L, and MT-ND6 genes.[1]
Last updated: 12/2/2011

What are the signs and symptoms of Leber hereditary optic neuropathy (LHON)?

Blurring and clouding of vision are usually the first symptoms of this disorder. 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, often leading to 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.[1] In rare cases, other symptoms may occur such as heart arrhythmias and neurologic abnormalities (e.g., postural tremor, peripheral neuropathy, nonspecific myopathy, movement disorders), and a multiple sclerosis-like disorder.[2]

However, a significant percentage of people with a mutation that causes Leber hereditary optic neuropathy do not develop any features of the disorder. Specifically, more than 50 percent of males with a mutation and more than 85 percent of females with a mutation never experience vision loss or related medical problems. Additional factors may determine whether a person develops the signs and symptoms of this disorder. Environmental factors such as smoking and alcohol use may be involved, although studies of these factors have produced conflicting results. Researchers are also investigating whether changes in additional genes, particularly genes on the X chromosome, contribute to the development of signs and symptoms.[1]
Last updated: 12/2/2011

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).[1]

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.[1] Click here to visit the Genetic Home Reference Web site to learn more about how mutations in these genes cause Leber hereditary optic neuropathy.
Last updated: 12/2/2011

How is Leber hereditary optic neuropathy (LHON) inherited?

Leber hereditary optic neuropathy is an inherited condition that has a mitochondrial pattern of inheritance. The gene mutations that cause this condition are found in the mitochondrial DNA. Mitochondria are inherited from a person's mother, and as a result, only females pass mitochondrial conditions on to their children. Men can be affected, but they cannot pass the condition on to their children.[1]

Often, people who develop the features of Leber hereditary optic neuropathy have no family history of the condition. Because a person may carry a mitochondrial DNA mutation without experiencing any signs or symptoms, it is hard to predict which members of a family who carry a mutation will eventually develop vision loss or other medical problems associated with Leber hereditary optic neuropathy. It is important to note that all females with a mitochondrial DNA mutation, even those who do not have any signs or symptoms, will pass the genetic change to their children.[1]
Last updated: 12/2/2011

References
  1. Leber hereditary optic neuropathy. Genetics Home Reference (GHR). 2006; http://ghr.nlm.nih.gov/condition/leber-hereditary-optic-neuropathy. Accessed 12/2/2011.
  2. Yu-Wai-Man P, Chinnery PF. Leber Hereditary Optic Neuropathy. GeneReviews. July 2011; http://www.ncbi.nlm.nih.gov/books/NBK1174/. Accessed 12/2/2011.