Kearns Sayre Syndrome: a rare muscle disease

Kearns Sayre syndrome (KSS) is a form of mitochondrial myopathy. This condition is a metabolic disease in which the mitochondrion does not function properly. The condition was first described by Thomas P. Kearns and George Pomeroy Sayre. As a result of the defect in the mitochondrion, patients with this condition suffer from a disruption in the energy supply of the muscle.

What is KSS?

Kearns Sayre syndrome (KSS) is a form of mitochondrial myopathy. This condition is a metabolic disease in which the mitochondrion does not function properly. Because the mitochondrion does not work properly, a number of muscles and organs do not receive enough energy. The most common complaints with KSS are drooping eyelids, muscle weakness, muscle pain, movement disorders and growth retardation. KSS is a rare condition and in the Netherlands there are twenty to thirty people who suffer from it.

What does a mitochondrion do?

The mitochondrion is the energy factory of a cell. Substances from fat and sugar are converted into energy with the help of oxygen. This happens in the mitochondrion. The energy produced ensures that organs function properly and that muscles move.

What is mitochondrial myopathy?

In people with mitochondrial disease, the mitochondria do not work properly. Something goes wrong in the process in which substances from fat and sugar are converted into energy. This causes a lack of energy. Mitochondrial myopathy involves a disruption of the muscle’s energy supply. Mitochondrial encephalomyopathy affects both the brain and the muscles. Kearns Sayre syndrome is therefore a form of mitochondrial myopathy.


The condition usually manifests before puberty. Patients with KSS usually suffer from drooping eyelids and have difficulty or even no movement of their eyes. In some cases, the facial muscles are also affected and a patient may have difficulty swallowing and speaking. About half of people with KSS suffer from other muscles such as the neck muscles and the shoulder girdle and pelvic girdle muscles. Cardiac arrhythmias also occur. If the disease starts early, there is a high chance of growth retardation and mental retardation can also occur. The disease is progressive, which means that the severity of the condition continues to increase.


Unfortunately, Kearns Sayre syndrome cannot yet be cured. However, it is possible to alleviate the symptoms. For example, surgery can be performed to make the eyelids droop less. Patients with cardiac arrhythmias can receive a pacemaker. The disease can affect life expectancy. To what extent this is the case depends on the severity of the condition, which differs in each patient.

How is the diagnosis made?

To determine whether someone has KSS, a number of tests are performed. For example, blood is taken to measure the lactate level (lactic acid). The urine will also be examined. A biopsy of the muscle will often be taken. This means that they take a piece of muscle from the body to examine. With KSS, the piece of muscle is examined for abnormalities in the muscle fibers. DNA testing is also possible.

I have KSS

Do you have KSS or another mitochondrial disease? Then you can get in touch with fellow sufferers on the site, they also have a Facebook page: