Kearns-Sayre Syndrome

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What is Kearns-Sayre syndrome?

Kearns-Sayre syndrome (KSS) is a rare neuromuscular disorder with onset usually before the age of 20. It is caused by abnormalities in mitochondria—small rod-like structures found in every cell of the body that produce the energy that drives cellular functions.

KSS is characterized by progressive limitation of eye movements until there is complete immobility, accompanied by eyelid droop. It is also associated with accumulation of pigmented material on the membrane lining the eyes. Additional symptoms may include:

  • Mild skeletal muscle weakness
  • Heart block (a cardiac conduction defect)
  • Short stature
  • Hearing loss
  • An inability to coordinate voluntary movements (ataxia)
  • Impaired cognitive function
  • Diabetes

Seizures are infrequent. Several endocrine disorders can be associated with KSS.

Treatment of KSS is symptomatic and supportive and involves multiple specialties depending on the organs involved. The most essential is a regular and long-term follow-up with cardiologists. Conduction problems of heart impulse like heart block may be treated with a pacemaker. Other consultations may include audiology, ophthalmology, endocrinology, neurology, and neuropsychiatry. Hearing aids may be required. There is typically no treatment for limitation in eye movement. Endocrine problems may be treated with drugs.

KSS is a slowly progressive disorder. The prognosis varies depending on the severity and the number of organs involved. Early diagnosis and periodic electrocardiograms (ECG) are important because heart block can cause death in 20 percent of individuals. Early pacemaker implantation can be of great benefit and offer a longer life expectancy in many individuals.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with Kearns-Sayre syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about KSS and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with KSS at

Where can I find more information about Kearns-Sayre syndrome?

The following organizations and resources help people living with KSS and their families, friends, and caregivers:


Muscular Dystrophy Association
Phone: 800-572-1717

National Organization for Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673; 844-259-7178 Spanish

United Mitochondrial Disease Foundation
Phone: 412-793-8077 or 888-317-8633

Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.