Autosomal dominant optic atrophy

Your optic nerves are vital for sight. They carry the electrical signals from your eye to the brain. The light sensitive photoreceptor cells in your retina at the back of your eye, convert light into electrical signals. These signals are sent along the optic nerve to your brain, where they are interpreted to “see” the world around us.

The start of the optic nerve is known as the optic disc. This is where all the individual nerve fibres from each of the photoreceptor cells in your retina come together. Your optic disc is visible as a small circular area of your retina.  It can be seen by the ophthalmologist (hospital eye doctor) or optometrist (optician) when they look into your eye. The nerve fibres travel together in a bundle, from your optic disc, forming your optic nerve.

ADOA causes gradual loss of vision in both eyes which is painless. It starts in childhood or teenage years but may not be diagnosed until adulthood in some people. Your vision can slowly worsen over time. ADOA also causes difficulties in recognising colours (dyschromatopsia). The amount of vision loss can vary from person to person, even in the same family. Children with sight loss due to ADOA usually adapt well. With the right help and support they can lead a full and enjoyable life.

Autosomal Dominant Optic Atrophy Plus (ADOA+)

Roughly 1 in 5 people with ADOA can have additional symptoms that affect other parts of their body. When this happens, it’s called autosomal dominant optic atrophy plus (ADOA+), and it usually comes with more severe visual loss.

Permanent hearing loss is the most common added symptom and occurs in roughly 2 out of 3 people with ADOA+. Hearing loss usually starts after sight loss, often in a person’s 20s or 30s.

Other conditions associated with ADOA+ can include:

• Weakness in the eye muscles (progressive external ophthalmoplegia)
• Muscle weakness (myopathy)
• Stiffness in the arms and legs (spasticity)
• Numbness or tingling in hands and feet (peripheral neuropathy)
• Cataracts, which can make vision cloudy.

ADOA is a genetic condition that affects the optic nerve, which carries visual information from your eyes to your brain. It happens because of a change (mutation) in one of the genes that helps keep the optic nerve healthy.

Your genes give the cells in your body the instructions they need to work well and stay healthy. If a gene has a mutation, the cells using those instructions can’t work as they should. In ADOA, the changed gene leads to a slow loss of nerve fibres that make up the optic nerve - the retinal ganglion cells (RGCs) and their axons. The RGCs and their axons gradually stop working over time. RGCs seem to be especially sensitive to problems caused by the gene change. 

So far, researchers have identified about eight different genes that can cause ADOA and are still discovering more. The names given to genes are often long, so they are usually identified using letters and numbers. About 75 out of 100 cases of ADOA are linked to a gene called OPA1.

Genes usually come in pairs. You inherit one copy of each gene from each of your parents to make a pair. When you have a child, you only pass on one of the two copies to them.

ADOA is mostly inherited (passed on in families) by autosomal dominant inheritance.

Autosomal dominant inheritance means that one parent has ADOA. Each time that parent has a child there is a 1 in 2 chance of the child having the condition as well.

Less commonly, OPA1-related ADOA can also be inherited in an autosomal recessive pattern. Recessively inherited ADOA means that neither parent has the condition themselves, but both parents are ‘carriers’. When both parents are carriers, every time they have a child, there is a 1 in 4 chance that the child will have the condition. Both parents need to be carriers of the condition for their child to be affected.

How can other family members be affected? 

The severity of ADOA can vary widely, both between different families and within the same family. Some people may have only mild vision problems, while others may be severely sight impaired.

Genetic testing uses a blood test to look at your genes to see if any changes are present. Genetic testing can be carried out to:

• Identify the specific gene change that is causing your condition.
• Indicate the inheritance pattern to show how likely it is for other members of your family to have the condition.
• Indicate whether you could pass on the gene change to your children.
• Indicate how your vision may change over time and with what speed.

There are several genetic centres around the country that carry out genetic tests. The service is provided free on the NHS if your  ophthalmologist or your GP refers you to one.

Genetic counselling is not talking therapy or an emotional support service.  Instead, it aims to provide the information you need to understand your condition. It can also enable you to make informed decisions relating to your condition.

Genetic counsellors are specialists in genetics and counselling. They work in genetic centres to offer you support around your test results. Genetic counselling can be invaluable even before genetic testing is carried out. It may prepare you for your results and what they may potentially mean for you.

If you know of a condition within your family, a genetic counsellor can provide you and your relatives with further information. They can explain how the condition has been passed on within your family by considering your family tree in detail. They can also offer you guidance and support in making any future decisions that may relate to your condition. For example, knowing the chances of passing on a condition may help if you are thinking about starting a family. Genetic counselling is a free service within the NHS. To access this service, you can ask your GP or ophthalmologist to refer you.

Currently there is no treatment to stop or reverse vision loss from ADOA.

There is ongoing research to improve early diagnosis and detection of hereditary optic neuropathies. Having a diagnosis early on can allow for timely care and support for those affected. It can also help support future trials into the condition. There is also early phase research into potential treatments.

When ADOA affects a person’s sight at any age, there are specialist support services which can help.

There is much that can be done to help make the most of your sight you have. This includes visual aids and adaptations around the home, adaptations and specialised software for computers at home and at work, and training from social services. Our Sight Loss Advice service can help provide information about all the different practical support available, contact our Helpline to speak with them. 

You can find out tips for making the most of your sight by downloading our booklet:

Other Useful Contacts:

Cure ADOA Foundation