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Kearns-Sayre Syndrome (KSS)

What is Kearns-Sayre syndrome?

Kearns-Sayre syndrome (KSS) is a rare disorder that impacts numerous parts of the body, with the eyes being majorly affected. Approximately 1 to 3 of every 100,000 people has this rare condition. 

What are the symptoms of Kearns-Sayre syndrome?

Many parts of the body are affected by Kearns-Sayre syndrome, particularly the eyes. Ocular symptoms include weak or paralyzed eye muscles, drooping eyelids, impaired eye movement, pigmentary retinopathy, and vision loss. 

Other possible symptoms include:

  • Ataxia
  • Cardiac conduction defects
  • High protein levels in the cerebrospinal fluid (CSF)
  • Deafness
  • Muscle weakness in the extremities
  • Dementia
  • Short stature
  • Kidney problems

What causes Kearns-Sayre syndrome?

Mitochondrial defects are responsible for Kearns-Sayre syndrome. To be specific, there is a deletion within the mitochondrial DNA (mtDNA). Anywhere from 1,000 to 10,000 nucleotides are deleted, resulting in a significant decrease in cellular energy production. Research still needs to be done to fully understand why this deletion occurs and how it causes the characteristic signs and symptoms.

The mutation responsible for this syndrome is somatic, meaning that it happens post-conception. In very rare cases, Kearns-Sayre syndrome is inherited in a mitochondrial pattern, meaning the mother passes down mutated mtDNA. 

How is Kearns-Sayre syndrome diagnosed?

In order to diagnose this condition doctors will look for three of the following characteristic symptoms, all of which must have occurred before age 20:

  • Changes in the eye’s structures
  • Paralysis in certain eye muscles
  • Heart disease
    • This is especially pertinent to conduction disorders like heart block
  • Atypical retinitis pigmentosa

If three of these symptoms are present, doctors can confirm a diagnosis through a clinical evaluation and specialized tests, such as electrocardiograms, blood tests, muscle biopsies, spinal taps, and in some cases, CT scans. 

What are the treatments for Kearns-Sayre syndrome?

Treatment for this syndrome is symptomatic; doctors will address the specific needs of each  patient. 

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


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