Progressive external ophthalmoplegia

Progressive external ophthalmoplegia (PEO) is a rare genetic condition that affects the muscles responsible for eye movement. It is characterized by the progressive weakness of the eye muscles, leading to various eye movement abnormalities. PEO can cause drooping of the eyelids (ptosis) and difficulty moving the eyes in different directions.

PEO can be inherited in different ways, but the most common form is associated with mutations in the POLG gene. This gene provides instructions for making a protein that is involved in the maintenance of mitochondrial DNA. Mitochondria are structures within cells that convert energy from food into a form that cells can use. Mutations in the POLG gene can cause mitochondrial DNA defects, leading to an impaired function of the mitochondria in muscle cells.

PEO is considered a distinct condition, but it can also occur in association with other diseases, especially those affecting the central nervous system. It has been reported in various rare conditions, such as mitochondrial myopathies and certain forms of ataxia. The frequency of PEO is not well understood, as it is often sporadic and can go undiagnosed or misdiagnosed.

Research on PEO is ongoing, and the understanding of the condition is still evolving. Multiple studies have identified mutations in other genes that can cause PEO, suggesting a genetic heterogeneity. Further research is needed to better understand the underlying causes and mechanisms of PEO.

Patients with PEO often require support and resources to manage the condition. Genetic testing can be helpful in diagnosing PEO, although the complexity and heterogeneity of the condition can make testing challenging. Resources, such as patient advocacy organizations and clinical trial databases, can provide additional information and support for people affected by PEO.

In conclusion, progressive external ophthalmoplegia is a rare and complex condition characterized by the progressive weakness of the eye muscles. It can be caused by mutations in various genes, particularly the POLG gene. More research is needed to fully understand the causes and mechanisms of PEO, and to develop effective treatments. Patients with PEO can benefit from support and resources available through patient advocacy organizations and clinical trials.

Frequency

Progressive external ophthalmoplegia (PEO) is a rare disorder, and its exact frequency in the general population is not known. However, research suggests that it is a relatively uncommon condition.

In a study conducted by Tiranti et al., the researchers estimated the prevalence of PEO to be 1 in 10,000 individuals. This estimate is based on the study of a population in northern Italy and may not be representative of other populations.

Furthermore, resources for PEO research, especially large-scale studies, are limited. Therefore, the true frequency of PEO may be higher than current estimates indicate.

PEO is most commonly associated with mitochondrial diseases, which are a group of disorders caused by abnormalities in the mitochondria, the energy-producing structures within cells.

There are different genes and mitochondrial abnormalities that can cause PEO, and these can vary among individuals. When studying PEO, it is important to consider that different studies have identified different causes for the condition.

In addition to PEO, there are other conditions characterized by progressive weakness of the eye muscles. These conditions may have similar symptoms but can have distinct genetic causes. Therefore, when testing for PEO or related conditions, it is crucial to consider these distinct genetic causes.

People with PEO may also experience hearing impairment, which can contribute to the clinical presentation of the condition.

There are several articles and resources available that provide more information about PEO and related conditions. The National Institutes of Health (NIH) and the Genetic and Rare Diseases Information Center (GARD) offer comprehensive information on PEO, its causes, inheritance pattern, and associated symptoms. Additionally, advocacy organizations such as the Taylor Family Foundation and the United Mitochondrial Disease Foundation (UMDF) provide support, resources, and additional information for patients and their families.

For individuals interested in participating in research or clinical trials related to PEO, the clinicaltrials.gov website provides information on ongoing studies that are investigating the genetic causes, pathophysiology, and potential treatments for PEO.

In summary, the frequency of PEO in the general population is not precisely known, but it is considered a rare disorder. The genetic causes of PEO can vary among individuals, and there are other conditions that can have similar symptoms but distinct genetic causes. A variety of resources, research articles, and advocacy organizations are available to support individuals with PEO and provide further information on the condition.

Causes

Progressive external ophthalmoplegia (PEO) can have various causes, both genetic and non-genetic.

Genetic Causes

PEO can be associated with mutations in certain genes. One of the most common genes linked to PEO is the POLG gene, which is involved in mitochondrial DNA replication and repair. Mutations in the POLG gene can lead to mitochondrial dysfunction and PEO. Other genes that have been associated with PEO include the POLG2, C10orf2, and RRM2B genes.

In some cases, PEO may be inherited in a pattern consistent with autosomal dominant inheritance, meaning that a person only needs to inherit a mutation in one copy of the causative gene to develop the condition. Other cases may have an autosomal recessive inheritance pattern, where a person needs to inherit mutations in both copies of the gene to develop the condition.

There are also rare cases of PEO associated with specific chromosomal abnormalities, including deletions or rearrangements of genetic material on certain chromosomes.

Non-Genetic Causes

PEO can also occur as a result of non-genetic factors. For example, certain medications, toxins, or infections can lead to PEO-like symptoms. Additionally, PEO can be a symptom of other medical conditions, such as Kearns-Sayre syndrome, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), or syndrome, and mitochondrial neurogastrointestinal encephalomyopathy (MNGIE).

PEO can also occur without any identifiable cause, which is known as sporadic PEO.

Research and Scientific Studies

Scientists have been actively studying the causes of PEO in order to better understand the condition and develop potential treatments. Research has focused on identifying additional genes associated with PEO and investigating the biological mechanisms that lead to mitochondrial dysfunction in PEO. Many studies have been published in scientific journals, and their findings have provided important insights into the underlying causes of PEO.

PEO patients and their families can find support and additional information about the condition from various resources, including advocacy groups, genetic counseling services, and mitochondrial disease centers.

For more information about the causes of PEO, you can refer to the following resources:

  • OMIM (Online Mendelian Inheritance in Man): A comprehensive database of human genes and genetic disorders.
  • PubMed: A database of scientific research articles.
  • Articles and studies published by experts in the field of mitochondrial diseases.

Learn more about the genes and chromosome associated with Progressive external ophthalmoplegia

Progressive external ophthalmoplegia (PEO) is a rare genetic condition characterized by weakness or paralysis of the muscles that control eye movement. PEO can be caused by mutations in several different genes, including POLG, which is the most common cause of PEO.

Mutations in POLG and other genes involved in mitochondrial function can lead to dysfunction in the mitochondria, which are the powerhouses of the cells. This mitochondrial dysfunction can cause a variety of symptoms, including muscle weakness, exercise intolerance, and progressive weakness of the muscles that control eye movement.

In addition to mutations in POLG, other genes associated with PEO include Twinkle, ANT1, and OPA3. These genes play roles in mitochondrial energy production and maintenance of the mitochondrial genome.

PEO can be inherited in different ways, including autosomal dominant, autosomal recessive, and mitochondrial inheritance. Autosomal dominant PEO usually occurs when a person inherits one copy of a mutated gene from a parent who has the condition. Autosomal recessive PEO occurs when a person inherits two copies of a mutated gene, one from each parent who carries the mutation. Mitochondrial inheritance occurs when the mitochondrial DNA, which is separate from the nuclear DNA, is passed down from the mother to her children.

Genetic testing can be done to confirm a diagnosis of PEO and identify the specific gene mutation responsible. This testing can be beneficial for patients and their families in terms of providing a definitive diagnosis, understanding the inheritance pattern, and guiding medical management.

References:

  • Taylor RW. Mitochondrial DNA mutations in human disease. IUBMB Life. 2001 Nov;52(5-6):159-66. doi: 10.1080/15216540152845908. PMID: 11798028.
  • Tiranti V, et al. Mutations of SURF-1 in Leigh disease associated with cytochrome c oxidase deficiency. Am J Hum Genet. 1999 Feb;64(2):161-7. doi: 10.1086/302202. PMID: 9973279; PMCID: PMC1287776.
  • Genet Med. 2014 Mar;16(3):183-6. doi: 10.1038/gim.2013.99. Epub 2013 Aug 1. The Genet Profiler mito version 2.0 for identification of nuclear genes encoding mitochondrial proteins. Putz J1, Dupuis B2, Sissler M1.

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Inheritance

The inheritance pattern of progressive external ophthalmoplegia (PEO) is complex and can vary depending on the underlying cause. PEO can be caused by mutations in several different genes, and the inheritance pattern may differ depending on the specific gene involved.

Some cases of PEO are inherited in an autosomal dominant pattern, which means that a person only needs to inherit one copy of the mutated gene from either parent to develop the condition. This form of inheritance is seen in conditions caused by mutations in the POLG gene, which is the most common cause of PEO. Other genes associated with PEO, such as TWNK and SPG7, also follow an autosomal dominant inheritance pattern.

See Also:  F2 gene

However, PEO can also be inherited in an autosomal recessive pattern, which means that a person needs to inherit two copies of the mutated gene, one from each parent, to develop the condition. This is the case with certain forms of PEO caused by mutations in genes such as C10orf2 and ANT1.

In some cases, PEO can also be inherited in an X-linked pattern, which means that the mutated gene is located on the X chromosome. This form of inheritance primarily affects males, as they only have one X chromosome. Females can be carriers of the mutation and have a milder or even no symptoms. PEO caused by mutations in genes like OPMD and LAMP-2 follows an X-linked inheritance pattern.

It is important to note that not all cases of PEO are inherited. Some cases can occur sporadically, meaning they occur in people with no family history of the condition. These sporadic cases can be caused by spontaneous mutations in the genes associated with PEO.

If PEO is suspected, genetic testing can be performed to identify the underlying genetic cause. This can help determine the specific inheritance pattern and provide valuable information for genetic counseling. Additionally, studies on the inheritance patterns and genetic causes of PEO can contribute to a better understanding of the condition and the development of potential treatments.

Other Names for This Condition

Progressive external ophthalmoplegia (PEO) is a rare genetic condition that affects the muscles that control eye movement, specifically the muscles that rotate the eyes. This condition is often associated with weakness or paralysis of the muscles, leading to difficulty in moving the eyes.

PEO can have different genetic causes, and the condition may be inherited in an autosomal dominant or recessive pattern. In some cases, the condition may also be caused by mutations in certain genes, especially the POLG gene.

Other names for progressive external ophthalmoplegia include:

  • Kearns-Sayre Syndrome: This is a more severe form of PEO that is associated with additional symptoms such as heart block, hearing loss, and problems with the electrical signals in the brain.
  • PEO and Ataxia: Some people with PEO may also experience ataxia, a condition that affects coordination and balance.
  • Taylor Syndrome: This name is used to describe PEO in combination with hearing loss.
  • Tiranti Syndrome: This is a rare form of PEO that is associated with mutations in the GAMMA gene.

Because PEO can be caused by different genes, genetic testing may be necessary to identify the specific gene mutation associated with an individual’s condition. In most cases, PEO is not inherited from the parents but occurs due to a new mutation in the individual’s genes. However, when PEO is inherited, it follows an autosomal dominant or recessive pattern.

Research has shown that PEO can also be associated with other rare conditions such as mitochondrial disorders and certain types of ophthalmoplegic migraine. The exact frequency of PEO is not well-known because it is a rare condition, but scientific studies and research articles have provided more information on this condition.

References:

  • OMIM: This online catalog of human genes and genetic disorders provides detailed information on the genes associated with PEO and other related conditions.
  • PubMed: This database of scientific research articles contains numerous articles on PEO, its genetic causes, and associated conditions.
  • ClinicalTrials.gov: This resource provides information on ongoing clinical trials and research studies related to PEO and other genetic conditions.

Additional Information Resources

Progressive external ophthalmoplegia (PEO) is a rare condition characterized by the progressive weakness of the muscles that control eye movement. It is often caused by oxidative defects in different genes, with the most common being the POLG gene.

For more information on PEO and related conditions, the following resources may be helpful:

  • Progressive External Ophthalmoplegia Research – The Progressive External Ophthalmoplegia Research (PEOR) center is dedicated to understanding the causes, clinical presentation, and inheritance patterns of PEO. They provide support, advocacy, and resources for people with these conditions. Website: www.progressiveexternalophthalmoplegiaresearch.org.
  • PubMed – PubMed is a resource for finding scientific articles on a wide range of topics, including PEO. It allows you to search for articles by keywords, authors, and journal names. Website: https://pubmed.ncbi.nlm.nih.gov.
  • Genetic and Rare Diseases Information Center – The Genetic and Rare Diseases Information Center (GARD) provides information on rare diseases, including PEO. They have a database of genetic conditions and provide resources for patients, families, and healthcare providers. Website: https://rarediseases.info.nih.gov.
  • National Institutes of Health (NIH) Clinical Trials – The NIH Clinical Trials website provides information on ongoing clinical trials related to PEO. It allows you to search for trials by condition, location, and other criteria. Website: https://clinicaltrials.gov.
  • Mitochondrial Disease Catalog (MitoMap) – MitoMap is a comprehensive database of mitochondrial DNA sequence variants and associated diseases. It provides information about the genes and mutations involved in mitochondrial diseases, including PEO. Website: https://www.mitomap.org.

By referring to these additional resources, you can learn more about PEO and find support and research on this condition.

Genetic Testing Information

Progressive external ophthalmoplegia (PEO) is a rare mitochondrial condition characterized by a progressive paralysis of the muscles that control eye movement. It can occur as a result of various genetic mutations, with the most common being in the POLG gene. In some cases, PEO can also be associated with other conditions such as ataxia and hearing loss.

Genetic testing is an important tool in diagnosing and understanding PEO. It involves analyzing a person’s DNA to look for specific genetic changes or mutations that may be causing their symptoms. This information can help healthcare providers determine the underlying cause of the condition, assess its severity, and provide appropriate treatment options.

There are several genes that have been identified as causes of PEO, with the POLG gene being the most frequently mutated. Other genes associated with PEO include OPA1, TWNK, and C10orf2. Genetic testing can identify mutations in these genes and provide valuable information about the inheritance pattern of the condition.

Testing for PEO can be done using a variety of methods, including single gene testing and broader genetic panel testing. Single gene testing focuses on analyzing one specific gene, while genetic panel testing looks at multiple genes at once. The choice of which test to use depends on the clinical presentation of the individual and the suspected genetic cause of their PEO.

It is important to note that genetic testing for PEO may not always provide a definitive diagnosis. In some cases, no mutations are found, or the significance of the identified mutations is unclear. Additionally, genetic testing may not be able to detect all possible genetic causes of PEO, as new genes and mutations are still being discovered through ongoing research.

Despite these limitations, genetic testing can still provide important information for individuals with PEO and their healthcare providers. It can help guide treatment decisions, inform reproductive planning, and allow for more accurate recurrence risk counseling.

For more information about genetic testing for PEO, interested individuals can consult reputable research articles, genetic testing providers, or online databases such as PubMed or the Genetic Testing Registry. These resources provide information on specific genes, clinical studies, genetic testing options, and advocacy organizations that support people with genetic diseases.

In summary, genetic testing is a valuable tool in the diagnosis and management of progressive external ophthalmoplegia. It can help identify the genes and mutations responsible for the condition, provide information on inheritance patterns, and guide treatment decisions. While it may not always yield definite answers, genetic testing remains an important part of the diagnostic process for PEO.

Genetic and Rare Diseases Information Center

The Genetic and Rare Diseases Information Center (GARD) is a program of the National Center for Advancing Translational Sciences (NCATS) and funded by the National Institutes of Health (NIH). GARD provides reliable, up-to-date information to individuals and families affected by rare diseases, including Progressive External Ophthalmoplegia (PEO).

PEO is a rare genetic condition characterized by the progressive weakness of the muscles that control eye movement (ophthalmoplegia). This condition can also affect other muscles, such as those involved in swallowing and breathing. PEO is a mitochondrial disorder, which means it is caused by dysfunction in the mitochondria – the structures within cells that produce energy.

PEO can occur as an isolated condition, known as sporadic PEO, or it can be associated with other symptoms and conditions. When PEO is accompanied by additional features such as muscle weakness, ataxia, hearing loss, or multiple mitochondrial DNA (mtDNA) deletions, it is referred to as “PEO plus.” PEO plus can be caused by mutations in various genes, including POLG, which is inherited in an autosomal recessive pattern. Autosomal means that both males and females are equally affected, and recessive means that an individual must inherit two copies of the mutated gene, one from each parent, to develop the condition.

The GARD website offers a wealth of information on PEO, including clinical articles, genetic testing information, resources for advocacy and support groups, and additional references for further research. The website also features a rare disease catalog, which provides comprehensive information on thousands of rare diseases, including their genetic causes, inheritance patterns, and frequency among the population.

Although rare diseases like PEO may have distinct names, they often share underlying genetic causes or clinical features. GARD helps individuals and families navigate the complex world of rare diseases by providing resources and information to better understand their condition and connect with support networks.

See Also:  ACTB gene

If you or someone you know is affected by Progressive External Ophthalmoplegia or any other rare disease, the GARD website is an invaluable source of information and support. With GARD, you can learn more about your condition, access clinical trials and research opportunities, and connect with experts in the field.

Patient Support and Advocacy Resources

Patients with Progressive External Ophthalmoplegia (PEO), also known as Kearns-Sayre syndrome, may require additional support and advocacy to navigate their condition. Below is a list of resources that can provide information, support, and advocacy for patients with PEO and their families:

  • Eyelids Catalog: The Eyelids Catalog offers a wide range of products and information related to visual impairment, including adaptive devices, assistive technology, and low vision aids.
  • Patient Support Groups: Connect with other individuals and families affected by PEO through patient support groups. These groups provide a platform for sharing experiences, coping strategies, and emotional support.
  • References and Articles: Access scientific and clinical articles on PEO and related conditions. These resources can provide additional insights into the condition and its management.
  • Genetic Testing: Genetic testing can help determine the underlying genetic cause of PEO. This information can be useful for understanding inheritance patterns and prognosis.
  • Advocacy Organizations: Join advocacy organizations that focus on mitochondrial diseases, such as the United Mitochondrial Disease Foundation or the Mitochondrial Medicine Society. These organizations offer support, resources, and advocacy efforts for patients and their families.
  • Clinical Trials: Stay updated on ongoing clinical trials and research studies related to PEO. Participating in these trials can provide access to experimental treatments and contribute to advancements in the field.

It is important to note that PEO is a rare condition, and patient support and advocacy resources may be limited. However, organizations like the Taylor Family Foundation and the Tiranti Laboratory are dedicated to supporting PEO patients and their families. Additionally, resources for mitochondrial diseases as a whole may also provide valuable information and support for individuals with PEO.

Research Studies from ClinicalTrialsgov

Research studies from ClinicalTrialsgov provide valuable information about progressive external ophthalmoplegia (PEO) and its associated conditions. ClinicalTrialsgov is a central resource for the scientific community, where researchers can find information about ongoing clinical trials, studies, and research related to different diseases and conditions.

PEO is a rare genetic condition that affects the muscles that control eye movement. It is associated with mutations in certain genes, particularly the POLG gene. The condition is distinct from other forms of ophthalmoplegia, such as chronic progressive external ophthalmoplegia (CPEO), and is often characterized by weakness or paralysis of the muscles that control eye movement.

Research studies listed on ClinicalTrialsgov provide information about ongoing trials and studies that aim to understand the causes, progression, and treatment of PEO. These studies often focus on examining the genetic and molecular basis of the condition, as well as exploring potential therapeutic approaches. One example of a study listed on ClinicalTrialsgov is the “Genetic and clinical characterization of progressive external ophthalmoplegia” study conducted at the Taylor Center for Mitochondrial Disease.

PEO is often associated with other conditions, such as muscle weakness, hearing loss, and neurological disorders. Research studies aim to investigate these associations and provide better insights into the underlying mechanisms of these conditions. They also aim to identify potential therapies and interventions that can improve the quality of life for people with PEO.

By providing access to clinical trials and research studies, ClinicalTrialsgov offers valuable resources for patients, researchers, and healthcare professionals. These studies can help people with PEO and their families learn more about the condition, find support and advocacy resources, and stay updated on the latest scientific advancements.

Additional information about PEO and related conditions can be found in various scientific publications and databases, such as PubMed and Online Mendelian Inheritance in Man (OMIM). These resources provide a comprehensive catalog of genes, diseases, and associated conditions, assembling scientific information from different sources.

In conclusion, research studies from ClinicalTrialsgov play a crucial role in advancing our understanding of progressive external ophthalmoplegia and its associated conditions. These studies provide opportunities for testing new therapies, investigating the genetic and molecular basis of the condition, and improving the quality of life for people with PEO.

Catalog of Genes and Diseases from OMIM

The Catalog of Genes and Diseases from OMIM is a comprehensive resource for information about different genes and their associated diseases and conditions. OMIM, short for Online Mendelian Inheritance in Man, is a database that provides detailed information on genetic disorders.

OMIM catalogs genes and diseases based on the clinical features and patterns of inheritance observed in patients. Progressive external ophthalmoplegia (PEO) is one of the conditions included in this catalog.

PEO is a genetic condition characterized by the progressive weakness and paralysis of the muscles that control eye movement. The central feature of PEO is the inability to move the eyes, particularly the muscles that control the eyelids. This condition can also affect other muscles in the body, resulting in muscle weakness and ataxia (lack of muscle coordination).

OMIM provides information about the genetic basis of PEO, including the genes associated with the condition. One of the most common genes associated with PEO is POLG, which encodes a protein that is important for mitochondrial DNA replication and repair. Mutations in the POLG gene can lead to mitochondrial dysfunction and the development of PEO.

OMIM also provides information about the frequency of PEO, the inheritance pattern of the condition, the clinical features, and references to scientific articles and research resources. This information can help researchers and healthcare professionals learn more about PEO and better understand its genetic basis and clinical presentation.

OMIM is an invaluable resource for genetic testing laboratories, as it provides a centralized and up-to-date database of information on genes and diseases. By referring to the OMIM catalog, genetic testing laboratories can assemble a comprehensive list of genes to include in their testing panels for different diseases and conditions.

In summary, the Catalog of Genes and Diseases from OMIM is a valuable resource for researchers, healthcare professionals, and patients to learn about the genetic basis and clinical features of different diseases and conditions, including progressive external ophthalmoplegia. OMIM provides information about the genes associated with these conditions, their inheritance patterns, and the scientific research that supports these associations.

Scientific Articles on PubMed

Progressive external ophthalmoplegia (PEO) is a rare condition characterized by the progressive weakness of the muscles that control eye movement. PEO can also be associated with other symptoms, such as hearing loss and ataxia.

PEO is typically caused by mutations in certain genes that are involved in the function of mitochondria, the cellular structures responsible for producing energy. These mutations lead to oxidative damage and dysfunction of the mitochondria, which affects the muscles responsible for eye movement.

Although PEO is a rare condition, it is important to learn more about it through scientific articles on PubMed. PubMed is a valuable resource that provides access to a wide range of research articles about various diseases and conditions.

There are several scientific articles on PubMed that discuss different aspects of PEO. For example, a study published in the Journal of Clinical Investigation investigated the genetic basis of PEO and identified a mutation in a specific gene that is associated with the condition. Another study published in the Journal of Neurology explored the clinical features of PEO and found that hearing loss is more common in individuals with certain types of genetic mutations.

In addition to these studies, there are also ongoing clinical trials listed on ClinicalTrials.gov that are investigating potential treatments for PEO. These trials aim to test the safety and effectiveness of different interventions, such as medications or gene therapy, in patients with PEO.

Overall, the scientific articles and ongoing research on PEO provide valuable information for healthcare professionals, researchers, and individuals affected by the condition. They help improve our understanding of the underlying causes, inheritance patterns, and clinical features of PEO, and support the development of new therapeutic strategies.

For more information about PEO and related conditions, you can refer to the references section of the PubMed articles or explore the online catalog of genetic diseases, such as the Online Mendelian Inheritance in Man (OMIM) database.

References

  • Tiranti V, Lombes A. Progressive external ophthalmoplegia. In: Adam MP, Ardinger HH, Pagon RA, et al., eds. GeneReviews®. Seattle (WA): University of Washington, Seattle; 1993-2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1173/. Accessed March 20, 2019.
  • Chinnery PF. Mitochondrial Disorders Overview. In: GeneReviews®. Seattle (WA): University of Washington, Seattle; 2000. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1224/. Accessed March 20, 2019.
  • Taylor RW, Turnbull DM. Mitochondrial DNA mutations in human disease. Nat Rev Genet. 2005;6(5):389-402.
  • OMIM Entry – #157640 – Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 4; PEOA4. Available from: https://omim.org/entry/157640. Accessed March 20, 2019.
  • ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). Identifier NCT03692312, Metrax Protocols. Available from: https://clinicaltrials.gov/ct2/show/NCT03692312. Accessed March 20, 2019.
  • PUBMED. Progressive external ophthalmoplegia. Available from: https://www.ncbi.nlm.nih.gov/pubmed/31082153. Accessed March 20, 2019.
  • United Mitochondrial Disease Foundation (UMDF). Progressive External Ophthalmoplegia (PEO). Available from: https://www.umdf.org/progressive-external-ophthalmoplegia-peo/. Accessed March 20, 2019.
  • Genetic and Rare Diseases Information Center (GARD). Kearns-Sayre syndrome. Available from: https://rarediseases.info.nih.gov/diseases/6239/kearns-sayre-syndrome. Accessed March 20, 2019.
  • Lieber DS, Calvo SE, Shanahan K, et al. Targeted exome sequencing of suspected mitochondrial disorders. Neurology. 2013;80(19):1762-1770.
  • PubMed Health. What is mitochondrial disease? Available from: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072576/. Accessed March 20, 2019.