Chronic Progressive External Ophthalmoplegia (CPEO)

Summary

Type of DNA affected

Mitochondrial or nuclear DNA

Common genetic change

Mitochondrial deletion

Typical age of onset

Early adulthood

Body area impacted

Eye muscles

Summary

Type of DNA affected

Mitochondrial or nuclear DNA

Common genetic change

Mitochondrial deletion

Typical age of onset

Early adulthood

Body area impacted

Eye muscles

Summary

Type of DNA affected
Mitochondrial or nuclear DNA

Common genetic change
Mitochondrial deletion

Age of onset
Early adulthood

Body area impacted
Eye muscles

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About CPEO

Chronic progressive external ophthalmoplegia, most commonly known as CPEO, is a rare inherited genetic condition. It is one of at least 350 known types of mitochondrial disease (mito).

Mito affects the mitochondria, which are tiny parts inside our cells that help make the energy our bodies need. When mitochondria do not work as they should, some parts of the body may not have enough energy to work properly, like your muscles or brain, to work the way they should. People with CPEO experience weakness in their eye muscles, which can impact vision.

When do symptoms appear?

CPEO usually starts in early adulthood, around 20, but can start at any age.¹ Symptoms can be more severe the earlier they start.² CPEO is progressive and can worsen over time. The main symptoms include:

weakness of eye muscles (ophthalmoplegia): The muscles that move your eyes may weaken, making it harder to move your eyes in different directions
drooping eyelids (ptosis): This is when your eyelids droop, which can affect your vision.

Curious about mito?

For more information, visit our understanding mito page. You’ll find explanations about what mito is, its symptoms, its causes, and how it affects the body.

Pronunciation

Chronic progressive external ophthalmoplegia (oph-thal-mo-ple-gia)

CPEO (C-P-E-O)

Other names for CPEO

progressive external ophthalmoplegia (PEO)

CPEO may also be referred to as:

Mitochondrial disease
Primary Mitochondrial Disease (PMD)
Mitochondrial myopathy

Planning for urgent care

If your mito specialist thinks you may get unwell quickly, they may give you an emergency plan. If you do not have a mito specialist, you could ask the specialist you see who knows about mito.

An emergency plan lists your diagnosis and care information from your care team. It can help to keep a copy with you. This could be on paper, on your phone or saved where you or your carer can find it fast. You can show the plan if you go to hospital, need an ambulance or see a new health professional. It can also help to keep current contact details for your main care team. This may include your general practitioner (GP), mito specialist or other specialist. You can also list other health professionals who know you well.

The Australian Patient Care Standards for mito and Important information about medicines can also help guide health professionals who are less familiar with mito.

Access the Australian Care standards for mito

Access important information about medicines

Hi. I'm Emy.

At 60, Emy noticed double vision. Years of tests and appointments followed before she was diagnosed with CPEO. Looking back, she realised she’d had symptoms for years.

Emy finds joy in helping others and believes staying busy keeps her well. But finds managing mito as an adult isolating. Emy wishes she had more specialist support. Her advice:

“Keep your brain busy and do what makes you feel alive.”

Beyond the basics

Learn more and find support to help you navigate your journey with mito.

Milestones Prevalence Symptoms Causes Diagnosis Care team Health care Clinical studies More to read Support groups

Milestones

1868: CPEO was first described by Dr. Albrech von Gräefe, he described a female, with partial ptosis and ophthalmoplegia.
1988: Dr Ian Holt and his colleagues discovered a genetic change responsible for CPEO. It is known as a single large-scale deletion of mitochondrial DNA (mtDNA).This led to researchers associating the genetic change as a cause of CPEO later that year.⁵
1992: Lewis Rowland defined CPEO as a syndrome in the Handbook of Clinical Neurology.⁶
2000: It was discovered that some cases of CPEO are caused by changes in other genes in the body, not just the mitochondrial DNA. This gave us a bigger picture of how CPEO can affect people.⁴
2005: Doctors created a set of guidelines to improve the diagnosis of CPEO.⁷
2010s: Researchers found that CPEO can cause other symptoms, like weakness in facial muscles or difficulty swallowing.
2020s and ongoing: Research continues to help us understand more about CPEO. Scientists are working on finding better ways to manage symptoms and improve life for people living with CPEO.

Prevalence

Symptoms

CPEO can be an isolated disorder or a multi-system disorder. CPEO can present differently in different people.

The main signs and symptoms are:

Impaired eye movements (ophthalmoplegia)

Ophthalmoplegia is the weakness of the muscles that move the eye (ophthalmoplegia). More specifically, external ophthalmoplegia affects the eye muscles responsible for movement. These muscles allow the eye to move in different directions, such as up, down, side to side, and in a circular motion. People with CPEO may have to turn their heads to see in different directions, especially as the ophthalmoplegia worsens.

Droopy eyelid(s) (ptosis)

Ptosis is when the upper eyelids droop, making it difficult to see properly. It can affect one or both eyelids. As ptosis worsens, you may use your forehead muscles to try to lift your eyelids or lift your chin to see.

Other signs and symptoms of CPEO:

Muscle weakness (myopathy)

Myopathy is a general weakness of the muscles used for movement, particularly those in the neck, arms, or legs. This weakness may be especially noticeable during exercise (exercise intolerance). Exercise intolerance is a reduced ability to engage in physical activity at a level typical for someone’s age and size. People with exercise intolerance may find themselves getting tired, out of breath, weak, or even nauseous. They get tired more quickly than expected during exercise.

Difficulty swallowing (dysphagia)

Dysphagia is when you have difficulty swallowing. Dysphagia happens because the muscles and nerves that help you swallow aren’t working properly. This can make it hard to move food from your mouth to your stomach. It might feel like food is getting stuck, or you experience choking episodes.

Other signs and symptoms

CPEO can also have other signs and symptoms. These include:

hearing loss from nerve damage in the inner ear (sensorineural hearing loss)
weakness and loss of feeling in the limbs from nerve damage (neuropathy)
impaired muscle coordination (ataxia)
a movement disorder called Parkinsonism
depression

When these signs and symptoms are diagnosed, the condition is called CPEO plus.

This section combines information from trusted sources.^6,9,10 The explanations have been adapted into plain language by Mito Foundation to support understanding within the mito community.

For more information

Understand the signs and symptoms of mito

Causes

CPEO is a genetic condition caused by genetic changes that affect metabolism,¹¹ which is how the body converts food into energy and removes waste. This process relies on hormones and enzymes to run smoothly. When a genetic change disrupts this process, it impacts mitochondrial function. Mitochondria are responsible for producing the energy your body needs, and when they can’t do this properly, it can make it difficult for parts of your body, like your muscles or brain, to function the way they should.

In CPEO, the eye muscles are particularly affected because they contain many mitochondria and are more sensitive to these genetic changes.¹² This leads to eye problems such as drooping eyelids (ptosis) and difficulty moving the eyes (ophthalmoplegia). CPEO can result from changes in mitochondrial DNA (mtDNA) or nuclear DNA (nDNA), which affect mitochondrial function. Genetic testing is important for diagnosing CPEO, but not all changes are easy to detect, so a thorough clinical evaluation is also essential.⁴

Mitochondrial DNA causes

De novo changes

A genetic change can occur randomly during conception. This means it is seen for the first time in a person and has not appeared in other family generations. This kind of change is called de novo, which means new.

About 60% of people with CPEO have changes in the mtDNA, known as deletions in mtDNA.¹³ These changes are usually de novo and occur during the formation of a mother's egg cells or in the early development of the embryo. There’s usually no family history of mito.¹⁴ Research suggests that the risk of passing this genetic change on to future generations is low.^14–16

Maternally inherited changes

DNA changes in the mitochondria (mtDNA) can cause CPEO. One example is the m.3243A>G change,¹⁷ which also causes MELAS. These changes in mtDNA are inherited from the mother (maternally inherited).

Carriers of mtDNA genetic changes

Within your cells, both healthy and changed mitochondria can exist. Known as heteroplasmy. Imagine having good and faulty machinery. Sometimes, the faulty machinery doesn’t cause immediate problems. When the change affects a large portion of mitochondria, symptoms can appear. These symptoms might skip a generation.

In a family, different organs can be affected differently. One family member might struggle with energy supply (due to the faulty machinery), while another seems fine. It’s because of this uneven distribution of healthy and changed mitochondria.

If the mother has no signs and symptoms of CPEO but carries the genetic change, she is known as a genetic carrier. All her children are at risk of inheriting the CPEO genetic change, but the severity can vary. Predicting who will develop symptoms and how severe they will be is challenging. Males with this mtDNA change cannot pass it on to their children.

Nuclear DNA causes

Changes in DNA found in the cell’s nucleus (nDNA) can change how mitochondria work. This happens because these changes can:

disrupt the production of new mtDNA
interfere with the supply of essential building blocks (nucleotides) for DNA
impact how mitochondria function.

About 40% of cases of CPEO are due to changes in nDNA. These genes include, but are not limited to:¹⁸

POLG
TWNK
RRM2B
SLC25A4

These genes are important for the creation and maintenance of mtDNA. Changes in these genes lead to the deletion of large segments of mtDNA. The size of the deletion can vary. Changes to the nDNA are transmitted in autosomal dominant, recessive, or X-linked dominant or recessive patterns depending on the affected gene.

nDNA genes that may cause CPEO

Making new mtDNA (synthesis of mtDNA):

POLG: This gene helps make new copies of mitochondrial DNA.
TWNK (aka C10ORF2): This gene helps unwind the DNA so it can be copied.
RNASEH1: This gene helps remove RNA pieces that are used during DNA copying.
MGME1: This gene helps cut and fix the DNA during copying.
DNA2: This gene helps repair and maintain the DNA.
POLG2: Works with POLG to help make new copies of mitochondrial DNA.

Recycling DNA building blocks (nucleotide metabolism):

TYMP: This gene helps recycle building blocks needed to make DNA.
RRM2B: This gene helps make the building blocks for DNA.
RRM1: Works with RRM2B to help make the building blocks for DNA.
GMPR: Helps in the recycling of nucleotides.

Regulating DNA building blocks:

TK2: This gene helps recycle old DNA building blocks.
DGUOK: This gene helps turn recycled building blocks into a form that can be used again.
ANT1: This gene helps bring the building blocks into the mitochondria.
MPV17: This gene helps keep the building blocks inside the mitochondria.

Others include:

OPA1: This gene helps mitochondria join and share their parts to stay healthy.
SPG7: Works with OPA1 to help mitochondria fuse together.
AFG3L2: Helps in the maintenance and fusion of mitochondria.
TOP3A: Helps in the maintenance and proper functioning of mitochondrial DNA.
C1QBP: Helps in the import and proper functioning of mitochondrial proteins.

The section combines information from several trusted sources.^4,19,20 The explanations have been adapted into plain language by Mito Foundation to support understanding within the mito community.

For more information

Learn more about genetics and mito

Information to understand your diagnosis

Information to understand your child’s diagnosis

Diagnosis

A diagnosis for CPEO is based on your history, signs and symptoms, physical examination, and other testing.

Physical exam

During a physical exam, your eyes and nervous system will be examined. Your health professional will check your eye muscles. They will test your ability to focus on targets and move your eyes in different directions. Additionally, they may measure your ptosis.

Your health professional may also refer you for more testing, such as:

Blood tests may be used to rule out other conditions. They look for the lack of specific antibodies for other conditions. These include myasthenia gravis and thyroid-related eye problems.
An electrocardiogram (ECG) checks your heart rhythm, or an echocardiogram (echo) may be required to look for heart muscle issues (cardiomyopathy).
A muscle biopsy may be needed. A muscle biopsy looks for “ragged red fibres” under a microscope, which is a sign of some types of mito, like CPEO.
Magnetic Resonance Imaging (MRI) is a noninvasive imaging method that may be needed as it can detect signs of eye muscle shortening or weakness (muscle atrophy) in CPEO.

Genetic testing

If your doctor suspects CPEO, they will arrange genetic testing to look for any changes associated with the condition. Usually, all that’s required is a blood or saliva sample. But sometimes, other samples like skin, hair, urine, or muscle are needed due to heteroplasmy (see causes of CPEO). If your health professional suspects CPEO, they may be able to order specific genetic tests that examine the genes known to cause CPEO.

Genetic testing is highly specialised, and it may take up to three to four months to receive the results. Genetic counselling is important to discuss what these results mean for you and your family.

For more information

Learn more about genetics and mito

Care team

If you have CPEO, you’ll likely need a team of health professionals to manage your care. Here are some health professionals who may be involved with your care:

General Practitioner (GP): your main point of contact. They can help with referrals, and tests, and coordinate your care.
Neurologist: specialises in nervous system disorders, and monitors progression.
Ophthalmologist: Monitors ptosis, ophthalmoplegia and peripheral vision.
Orthoptist: works with an ophthalmologist to test vision and uses specialised diagnostic tests to detect and examine the visual system's function.
Cardiologist: accesses and monitors heart conditions.
Genetic Counselor: provides education and support for people with genetic health conditions.
Physiotherapist: helps with mobility and strength.
Speech Therapist: addresses and manages swallowing difficulties (dysphagia) if present.
Occupational Therapist: assists with daily living activities and maintaining quality of life.
Mental health professional: offers mental health and wellbeing support.

For more information

Information to build your care team

Information to build your child’s care team

Health care

Regular monitoring for mito is important. Your health professional may recommend different tests. These tests help check how mito is affecting you. Learn more about monitoring mito for adults, or children.

The following recommendations have been adapted from the Australian Patient Care Standards for mito:²¹

Eye care (Ophthalmology)

If you have CPEO, it's essential to see an ophthalmologist for a thorough assessment. This includes:

checking your visual acuity
assessing your visual fields
examining your eye movements
assessing any drooping eyelids (ptosis)

If your vision is impaired, consider seeing a low-vision specialist. Surgery may be an option for conditions like strabismus or ptosis.

Annual visits with your ophthalmologist are recommended for ongoing monitoring. This involves:

checking for changes in your vision
checking the health of your retina and macula
measuring your intraocular pressure
evaluating the health of your optic nerve
If you have the m.3243A>G genetic change, it's important to watch for signs of maculopathy.

If you find it difficult to close your eyelids due to ptosis or after ptosis surgery, consider using methylcellulose eye drops or ointments to keep your eyes lubricated and relieve dry, irritated eyes. Ask your health professional which artificial tears are best for you.

Brain and nerve care (Neurology)

Pain

Headaches and migraines are treated the same whether you have mito or not. A sudden increase in migraine severity or new neurological symptoms may indicate a change in your health. In children, particularly those with intellectual disabilities, irritability and personality changes can be indicators of pain. Talk to your health professional about any changes to your condition.

Learn more about pain and mito

Myopathy

Keep an eye on any changes or worsening of your myopathy symptoms. If you notice anything different, talk to your neurologist or GP. They might do blood tests to check for high enzyme levels or other causes, which could involve various tests.

When managing myopathy as part of mito, it’s essential to be proactive about your health. It’s always best to discuss these aspects with your health professional to get advice that fits your situation.

Exercise

To prevent muscle breakdown exercise is beneficial, but it should be tailored to your needs and capabilities. Before starting any exercise program, your heart function should also be checked to ensure it’s safe to proceed.

Once you have discussed changes to your exercise with your health professional, it may be safe for you to begin. Moderate-intensity aerobic exercise is recommended. Aiming for 70% of your maximum heart rate helps improve your fitness. However, this is not recommended if you have heart issues. Always speak to your mito specialist and cardiologist before starting a new exercise regimen.

Physical therapy and regular assessments can help maintain mobility and prevent complications. To create a personalised exercise plan, speak to a professional such as an exercise therapist or physiotherapist.

Learn more about exercise and mito

Looking after your mental health (psychology)

Taking care of your mental health is just as important as managing physical symptoms when dealing with CPEO. If you have any psychiatric symptoms, such as anxiety, depression or memory loss, speak to your health professional.

For children, it’s particularly important to watch for low self-esteem and anxiety. Addressing these feelings early can make a big difference in their emotional wellbeing.

Medicines to be used with caution

Certain medications can affect your muscles. They are:

statins for high cholesterol
metformin for blood sugar control
corticosteroids for inflammation like asthma
antiretrovirals for viral infections such as HIV.

They should be used with caution. If you are prescribed any of these medications, regular monitoring is crucial to avoid worsening your myopathy.

Other medications include:

If you have optic atrophy or mtDNA depletion syndrome, a seizure medication called vigabatrin should be used with caution.
Valproate is used for the management of seizures and may be harmful (contraindicated). Especially for those with POLG genetic changes, due to its potential to worsen seizures and risk of liver failure.

If you are unsure, always speak to your health professional.

For more information

Access the Patient Care Standards for Mito

Clinical studies

Mito Foundation provides information to help people affected by mito understand clinical trials and how to find opportunities that may be relevant to them.

Clinical trials help researchers test new ways to prevent, diagnose, treat and manage mito. Some trials test whether a treatment is safe and whether it may help people.
Other clinical studies may look at symptoms, diagnosis, genetics, quality of life, or how mito affects people over time.
Clinical trials are carefully planned. The therapies being studied may be at different stages. Trials may not be available for every type of mito, and not every trial will be right for you. Some trials are only open to people with a confirmed genetic diagnosis, specific symptoms, a certain age range, or the ability to attend study appointments.

Mito Foundation’s emerging therapies information explains therapies in development, how clinical trials work, and what you may wish to consider before taking part. You can also use the Therapy Finder to explore therapies in development and see what may be relevant to you.

Learn more about taking part in clinical trials
Use the Therapy Finder

Staying informed

One way to hear about opportunities to take part in clinical trials is to join the Mito Registry.

The Mito Registry helps connect people with research opportunities that may be relevant to them. It also helps Mito Foundation understand how many people in Australia are affected by different types of mito.

This information can help support future research, services and advocacy.

Join the Mito Registry

More to read

Support groups

Mito Foundation support services

Helpline

Call Helpine for general advice, assistance in seeking a referral or more information on Mito Foundation support services.

Contact Helpline

Events

Mito Foundation events bring together people impacted by mitochondrial disease (mito).

Learn more about events

NDIS support

Access the NDIS Navigation Service (NNS) for resources, education and 1:1 guidance on the NDIS.

Learn more about NNS

References

Heighton JN, Brady LI, Sadikovic B, Bulman DE, Tarnopolsky MA. Genotypes of chronic progressive external ophthalmoplegia in a large adult-onset cohort. Mitochondrion [Internet]. 2019 [cited 2025 Mar 25];49:227–31. Available from: https://www.sciencedirect.com/science/article/pii/S1567724918300965
Auré K, Ogier de Baulny H, Laforêt P, Jardel C, Eymard B, Lombès A. Chronic progressive ophthalmoplegia with large-scale mtDNA rearrangement: can we predict progression? Brain. 2007;130(6):1516–24.
Arena IG, Pugliese A, Volta S, Toscano A, Musumeci O. Molecular genetics overview of primary mitochondrial myopathies. J Clin Med [Internet]. 2022 [cited 2025 Mar 25];11(3):632. Available from: https://www.mdpi.com/2077-0383/11/3/632
Ali A, Esmaeil A, Behbehani R. Mitochondrial Chronic Progressive External Ophthalmoplegia. Brain Sci [Internet]. 2024 [cited 2025 Mar 25];14(2):135. Available from: https://www.mdpi.com/2076-3425/14/2/135
Deletions of muscle mitochondrial DNA in patients with mitochondrial myopathies | Nature [Internet]. [cited 2025 Mar 25]. Available from: https://www.nature.com/articles/331717a0
Hirano M, Pitceathly RD. Progressive external ophthalmoplegia. Handb Clin Neurol [Internet]. 2023 [cited 2025 Mar 25];194:9–21. Available from: https://www.sciencedirect.com/science/article/pii/B978012821751100018X
Richardson C, Smith T, Schaefer A, Turnbull D, Griffiths P. Ocular motility findings in chronic progressive external ophthalmoplegia. Eye [Internet]. 2005 [cited 2025 Mar 25];19(3):258–63. Available from: https://www.nature.com/articles/6701488
Domenis DR, Granzotti RB, Sobreira CF, Dantas RO. Pharyngeal transit in patients with chronic progressive external ophthalmoplegia. Int J Speech Lang Pathol [Internet]. 2015 Jul 4 [cited 2025 Mar 25];17(4):384–9. Available from: http://www.tandfonline.com/doi/full/10.3109/17549507.2014.941935
Hanisch F, Kornhuber M, Alston C, Taylor RW, Deschauer M, Zierz S. SANDO syndrome in a cohort of 107 patients with CPEO and mitochondrial DNA deletions. J Neurol Neurosurg Psychiatry [Internet]. 2014 [cited 2025 Mar 25];86:630–4. Available from: https://pubmed.ncbi.nlm.nih.gov/25143630/
Lv Z, Xu X mei, Cao XF, Wang Q, Sun D fang, Tian W jing, et al. Mitochondrial mutations in 12S rRNA and 16S rRNA presenting as chronic progressive external ophthalmoplegia (CPEO) plus. Medicine (Baltimore) [Internet]. 2017 [cited 2025 Mar 25];96. Available from: https://pubmed.ncbi.nlm.nih.gov/29310369/
Elstner M, Olszewski K, Prokisch H, Klopstock T, Murgia M. Multi-Omics Approach to Mitochondrial DNA Damage in Human Muscle Fibers. Int J Mol Sci [Internet]. 2021 [cited 2025 Mar 25];22. Available from: https://pubmed.ncbi.nlm.nih.gov/34681740/
Greaves LC, Yu-Wai-Man P, Blakely E, Krishnan KJ, Beadle NE, Kerin J, et al. Mitochondrial DNA defects and selective extraocular muscle involvement in CPEO. Invest Ophthalmol Vis Sci [Internet]. 2010 [cited 2025 Mar 25];51 7:3340–6. Available from: https://pubmed.ncbi.nlm.nih.gov/20164463/
Lee AG, Brazis PW. Chronic progressive external ophthalmoplegia. Curr Neurol Neurosci Rep [Internet]. 2002 Oct [cited 2025 Mar 25];2(5):413–7. Available from: http://link.springer.com/10.1007/s11910-002-0067-5
Sallevelt SCEH. Preventing the transmission of mitochondrial diseases. 2017 [cited 2025 Mar 25]; Available from: https://cris.maastrichtuniversity.nl/files/7162664/v5582.pdf
Goldstein A, Falk MJ. Mitochondrial DNA deletion syndromes. 2019 [cited 2025 Mar 25]; Available from: https://europepmc.org/books/nbk1203
Smeets HJM, Sallevelt SCEH, Dreesen JCFM, De Die‐Smulders CEM, De Coo IFM. Preventing the transmission of mitochondrial DNA disorders using prenatal or preimplantation genetic diagnosis. Ann N Y Acad Sci [Internet]. 2015 Sep [cited 2025 Mar 25];1350(1):29–36. Available from: https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.12866
Nesbitt V, Pitceathly R, Turnbull D, Taylor RW, Sweeney M, Mudanohwo E, et al. The UK MRC Mitochondrial Disease Patient Cohort Study: clinical phenotypes associated with the m.3243A>G mutation—implications for diagnosis and management. J Neurol Neurosurg Psychiatry [Internet]. 2013 [cited 2025 Mar 25];84:936–8. Available from: https://pubmed.ncbi.nlm.nih.gov/23355809/
Finsterer J. Mitochondrial Ophthalmoplegia Is Not Only due to mtDNA Deletions. Yonsei Med J [Internet]. 2019 [cited 2025 Mar 25];60:230–1. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6342708/
López-Gómez C, Cámara Y, Hirano M, Martí R. 232nd ENMC international workshop: Recommendations for treatment of mitochondrial DNA maintenance disorders. 16–18 June 2017, Heemskerk, The Netherlands. Neuromuscul Disord [Internet]. 2022 [cited 2025 Mar 25];32(7):609–20. Available from: https://www.sciencedirect.com/science/article/pii/S0960896622001456
Van Goethem G, Martin JJ, Van Broeckhoven C. Progressive External Ophthalmoplegia Characterized by Multiple Deletions of Mitochondrial DNA: Unraveling the Pathogenesis of Human Mitochondrial DNA Instability and the Initiation of a Genetic Classification. NeuroMolecular Med [Internet]. 2003 [cited 2025 Mar 25];3(3):129–46. Available from: http://link.springer.com/10.1385/NMM:3:3:129
Sue CM, Balasubramaniam S, Bratkovic D, Bonifant C, Christodoulou J, Coman D, et al. Patient care standards for primary mitochondrial disease in Australia: an Australian adaptation of the Mitochondrial Medicine Society recommendations. Intern Med J [Internet]. 2022 Jan [cited 2025 Mar 25];52(1):110–20. Available from: https://onlinelibrary.wiley.com/doi/10.1111/imj.15505

Disclaimer: Resources provided by the Australian Mitochondrial Disease Foundation Limited (Mito Foundation), offers general information and is not a substitute for medical advice. It is essential to assess the suitability of the content for your individual circumstances and make decisions based on your medical condition. The information’s accuracy is subject to change, and we do not guarantee ongoing currency or availability. While efforts are made to ensure accuracy, Mito Foundation is not obligated to provide updated information. The copyright for this document and its content belongs to, or is licensed to, Mito Foundation, and reproduction without prior written consent is prohibited.

Acknowledgement: Mito Foundation acknowledges the valuable contributions of our reviewers, we thank Professor Clare Fraser, Ophthalmologist, MBBS FRANZCO and Dr Isabel Lopez Sanchez, Research Manager, for their review. As well as Diane, Pam, and Zach, members of the Mito Community Resource Review Panel.

Author: Mito Foundation
Version: 1
Date published: Monday 16 June 2025

What is CPEO? Causes, symptoms and support

Summary

Type of DNA affected

Common genetic change

Typical age of onset

Body area impacted

Summary

Type of DNA affected

Common genetic change

Typical age of onset

Body area impacted

Summary

Prefer to listen?

About CPEO

When do symptoms appear?

Other conditions linked to CPEO

Curious about mito?

Pronunciation

Other names for CPEO

Planning for urgent care

Hi. I'm Emy.

Beyond the basics

Mito Foundation support services

Helpline

Events

NDIS support

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