Hereditary Optic Neuropathies
What are Hereditary Optic Neuropathies?
Hereditary optic neuropathies are conditions in which genetic defects cause vision loss by damaging the optic nerve, which carries visual information from the eye to the brain.
Hereditary optic neuropathies include:
- Leber hereditary optic neuropathy – This form is caused by a mutation in the mitochondrial DNA, meaning it can only be inherited from the mother. Some individuals are only carriers and do not experience vision loss, while others may suffer permanent vision loss.
- Autosomal dominant optic atrophy – In this form, the mutated gene is a dominant gene located on an autosome, which is a nonsex chromosome. An individual only needs one mutated gene to be affected.
Symptoms of Hereditary Optic Neuropathies
Leber hereditary optic neuropathy usually begins with painless blurring or clouding of central vision in one eye, with symptoms affecting the other eye within several weeks or months. However, vision loss can occur in both eyes simultaneously. Vision loss improves in a small percentage of cases, but it is usually progressive and permanent.
In autosomal dominant optic atrophy, vision loss usually affects both eyes simultaneously. It usually progresses slowly, and the severity varies per person.
Vision loss can be a symptom of many other health conditions. Contact a medical professional if you are having vision problems.
There is currently no approved treatment for hereditary optic neuropathies, but low-vision aids may be helpful.
How common are hereditary optic neuropathies?
Autosomal dominant optic atrophy is believed to be the most common of the hereditary optic neuropathies, with a prevalence ranging from 1 in 10,000 people to 1 in 50,000 people.
Who gets hereditary optic neuropathies?
Hereditary optic neuropathies are caused by genetic defects.
Leber hereditary optic neuropathy usually begins in a person’s teens or twenties, and it affects males more than females.
Autosomal dominant optic neuropathy usually presents in the first decade of life, although the gradual progression can make it difficult to identify the exact time of onset.
How are hereditary optic neuropathies diagnosed?
A blood test can determine whether or not you carry the mitochondrial mutation for Leber hereditary optic neuropathy. There is no fast, simple DNA test for autosomal dominant optic atrophy because many different genetic mutations can cause the condition.
The following may also be used to diagnose a hereditary optic neuropathy:
- Eye examination
- Medical history
- Imaging tests