Autosomal dominant optic atrophy

What is autosomal dominant optic atrophy?

Autosomal dominant optic atrophy (ADOA) is a rare genetic condition caused by the deterioration of the optic nerve, which transmits visual information from the eyes to the brain. It causes progressive and irreversible sight loss in both eyes.

Autosomal dominant optic atrophy 'plus' is the most severe version, which can also cause hearing loss and mobility issues.

What causes autosomal dominant optic atrophy?

Autosomal dominant optic atrophy is an inherited condition caused by genetic mutations, which stop the mitochondria (the tiny energy generators inside your cells) from working properly. Cells containing these poorly functioning mitochondria can die prematurely – particularly cells with high energy demands, such as nerve cells. 

This leads to the death of retinal ganglion cells in the inner retina (the light-sensitive layer at the back of the eye). Specialised extensions of retinal ganglion cells, called axons, form the optic nerve. The death of these cells leads to the degeneration of the optic nerve, which disrupts the transmission of visual information from the eyes to the brain, causing sight loss.

Autosomal dominant optic atrophy ‘plus’ syndrome is caused when nerve cells in other parts of the body are also affected by poorly functioning mitochondria.

Mutations that cause ADOA in more than 20 genes have so far been identified. In about three quarters of cases, the gene involved is OPA1, which contains the instructions for a protein made in many cells and tissues throughout the body. The OPA1 protein plays a crucial role in the normal functioning of mitochondria, and there are high levels of it in the retinal ganglion cells that make up the optic nerve.

Each child of a parent with the condition will have a one in two (50%) chance of inheriting it. Sometimes, you can inherit the faulty gene running in the family without going on develop visual loss – this is known as non-penetrance.

In rare cases, the genetic fault can also occur spontaneously in a child whose parents are unaffected.

What are the signs and symptoms of autosomal dominant optic atrophy?

Autosomal dominant optic atrophy causes blurred vision in both eyes,  and difficulty in recognising colours (colour blindness). Usually your central vision is more badly affected than your peripheral vision (what you can see at the edges of your visual field).

It usually starts in early childhood (before the age of ten, although later is possible) and gradually worsens over time.

The most severe form, autosomal dominant optic atrophy “plus” syndrome, can lead to hearing loss (usually later in life after vision loss has begun) and other symptoms, including numbness, muscle weakness, muscle stiffness and balancing difficulties, leading to mobility problems.

How is autosomal dominant optic atrophy diagnosed?

A diagnosis of autosomal dominant optic atrophy is usually made based on clinical features, family history, and the results of an eye examination. Tests may include:

• Visual acuity test – to measure the sharpness of vision in each eye
• Visual field testing – to measure the extent of vision loss in the central and peripheral fields
• Colour vision testing 
• Optical coherence tomography (OCT) – taking a picture of the back of the eye to examine all the layers of the optic nerve and retina in detail
• Electroretinogram (ERG) – to test the electrical activity of the optic nerve and retina in response to light
• Genetic testing – to confirm a diagnosis of autosomal dominant optic atrophy by identifying faults in one of the genes associated with the condition.

What are the treatments for autosomal dominant optic atrophy?

Unfortunately, no treatment currently can prevent or reverse sight loss caused by autosomal dominant optic atrophy. Wearing prescription glasses or contact lenses can be helpful. 

For people with ADOA who have hearing loss, hearing aids or cochlear implants can help to improve or restore their hearing.

What can help autosomal dominant optic atrophy?

People with autosomal dominant optic atrophy plus syndrome could benefit from seeing a neurologist to help minimise some of their symptoms with the appropriate treatment.

Supportive measures such as low vision assessments, visual aids, and assistive technology can also help make the most of the remaining vision and improve quality of life.

What research is there into autosomal dominant optic atrophy?

We've been funding scientists searching for other genes that cause different types of inherited optic atrophy, aiming to improve diagnosis and understanding of the condition, which could open new treatment avenues.

The Cameron Family Fund is fundraising for pioneering research into ADOA to help those diagnosed with the condition.

See our research projects