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Optic atrophy type 1
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Reviewed June 2009
What is optic atrophy type 1?
Optic atrophy type 1 is a condition that affects vision. Individuals with this condition have progressive vision loss that typically begins within the first decade of life. The severity of the vision loss varies widely among affected people, even among members of the same family. People with this condition can range from having nearly normal vision to complete blindness. The vision loss usually progresses slowly.
People with optic atrophy type 1 frequently have problems with color vision that make it difficult or impossible to distinguish between shades of blue and green. Other vision problems associated with this condition include a progressive narrowing of the field of vision (tunnel vision) and an abnormally pale appearance (pallor) of the nerve that relays visual information from the eye to the brain (optic nerve). Optic nerve pallor can be detected during an eye examination.
How common is optic atrophy type 1?
Optic atrophy type 1 is estimated to affect 1 in 50,000 people worldwide. This condition is more common in Denmark, where it affects approximately 1 in 10,000 people.
What genes are related to optic atrophy type 1?
Optic atrophy type 1 is caused by mutations in the OPA1 gene. The protein produced from this gene is made in many types of cells and tissues throughout the body. The OPA1 protein is found inside mitochondria, which are the energy-producing centers of cells. The OPA1 protein plays a key role in the organization of the shape and structure of the mitochondria and in the self-destruction of cells (apoptosis). The OPA1 protein is also involved in a process called oxidative phosphorylation, from which cells derive much of their energy. Additionally, the protein plays a role in the maintenance of the small amount of DNA within mitochondria, called mitochondrial DNA (mtDNA).
Mutations in the OPA1 gene lead to overall dysfunction of mitochondria. The structure of the mitochondria become disorganized and cells are more susceptible to self-destruction. OPA1 gene mutations lead to mitochondria with reduced energy-producing capabilities. The maintenance of mtDNA is also sometimes impaired, resulting in mtDNA mutations.
The vision problems experienced by people with optic atrophy type 1 are due to mitochondrial dysfunction, leading to the breakdown of structures that transmit visual information from the eyes to the brain. Affected individuals first experience a progressive loss of nerve cells within the retina, called retinal ganglion cells. The loss of these cells is followed by the degeneration (atrophy) of the optic nerve. The optic nerve is partly made up of specialized extensions of retinal ganglion cells called axons; when the retinal ganglion cells die, the optic nerve cannot transmit visual information to the brain normally.
It is unclear why the OPA1 gene mutations that cause optic atrophy type 1 only affect the eyes. Retinal ganglion cells have many mitochondria and especially high energy requirements, which researchers believe may make them particularly vulnerable to mitochondrial dysfunction and decreases in energy production.
Some individuals with optic atrophy type 1 do not have identified mutations in the OPA1 gene. In these cases, the cause of the condition is unknown.
Read more about the OPA1 gene.
How do people inherit optic atrophy type 1?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
Where can I find information about diagnosis or management of optic atrophy type 1?
These resources address the diagnosis or management of optic atrophy type 1 and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about optic atrophy type 1?
You may find the following resources about optic atrophy type 1 helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for optic atrophy type 1?
What if I still have specific questions about optic atrophy type 1?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding optic atrophy type 1?
apoptosis ; atrophy ; autosomal ; autosomal dominant ; axons ; cell ; DNA ; gene ; juvenile ; mitochondria ; mutation ; optic atrophy ; optic nerve ; oxidative phosphorylation ; pallor ; phosphorylation ; protein ; retina ; retinal ganglion ; retinal ganglion cells
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.