Kearns-Sayre syndrome is a rare condition caused by changes to mitochondrial DNA. Its symptoms affect the eye as well as other areas of the body.
Kearns-Sayre syndrome (KSS) is a rare neuromuscular disorder that is caused by abnormalities in mitochondria. Mitochondria are small structures in cells that produce the energy needed for your cells to function.
KSS is rare. Researchers estimate that it affects
KSS is a type of mitochondrial encephalomyopathy, meaning that it can cause a variety of problems with muscles and the nervous system. The symptoms of KSS affect the eyes as well as other parts of the body.
Your mitochondria contain a small amount of their own DNA. This is called mitochondrial DNA.
KSS is caused by changes to your mitochondrial DNA.
These deletions can vary in size. However, the most common one involves the deletion of almost 5,000 base pairs and accounts for
You inherit your mitochondrial DNA from your mother. As such, in very rare cases, you may also inherit KSS.
The symptoms of KSS typically come on
Chronic progressive external ophthalmoplegia (CPEO)
CPEO is a progressive weakening of eye muscles. Progressive means that the condition gets worse as time passes.
CPEO may first appear as a drooping eyelid. Over time, people with KSS may need to use their forehead muscles to help raise their eyelids or may lift their chin in order to see better.
Weakening of the eye muscles can make it difficult to move the eyes. Due to this, people with KSS may turn their heads in order to see objects located in the periphery of their vision.
It’s possible for CPEO to be associated with muscle weakness in other parts of the body as well, such as the face, throat, and limbs. This can lead to symptoms like:
- difficulty speaking or swallowing
- worsening weakness in the arms and legs
- exercise intolerance
- uncoordinated muscle movement, called ataxia
People with KSS have a buildup of pigmented material in the tissues lining the eye, giving it a “salt-and-pepper” appearance. This can lead to damage of the retina, the part of your eye that converts light into nerve signals that your brain can process.
The effects of pigmentary retinopathy can lead to a variety of vision problems, including:
Other symptoms of Kearns-Sayre syndrome
In addition to what’s discussed above, people with KSS may also have other signs and symptoms as well. These include:
The symptoms of KSS can resemble those of other health conditions, particularly other mitochondrial disorders. KSS can be suspected when the three primary findings discussed above are present and symptom onset is by age 20.
The first part of the diagnostic process involves your doctor getting a thorough medical history and doing a physical and eye exam. They’ll then order tests to help rule out other conditions and confirm the diagnosis.
Some of the tests that may be done are:
KSS is associated with a variety of complications. These can include:
- increasing trouble with eye or other muscle movement
- vision loss
- hearing loss
There’s no cure for KSS. Additionally, because KSS is progressive, its symptoms will continue to worsen as time passes. Treatment for KSS is targeted at managing symptoms, preventing complications, and boosting quality of life.
Typically, a variety of different healthcare professionals are involved in treating KSS. These can include, but aren’t limited to:
- metabolic specialists
- geneticists or genetic counselors
Some of the potential treatments for KSS include:
- implantation of a pacemaker to prevent complications from heart block
- surgery to help with drooping eyelid or with vision problems
- hearing aids or cochlear implants
- medications to manage endocrine problems like diabetes
The outlook for KSS can depend on the severity of symptoms and the specific parts of the body impacted. Generally speaking, early diagnosis and treatment can help to improve outlook.
KSS is a condition that affects cellular mitochondria. It’s typically caused by spontaneous deletions of mitochondrial DNA, but can occasionally be inherited.
The key findings in KSS include progressive weakening of the eye muscles, pigmentary retinopathy, and heart block. Other signs and symptoms may be present as well.
KSS is a progressive condition for which there’s no cure at this time. Treatment aims to manage symptoms, prevent complications, and improve quality of life. The outlook for KSS depends on its severity and the parts of the body affected.