What is Kearns-Sayre Syndrome?

Kearns-Sayre syndrome, or KSS, is a neuromuscular disorder that usually only affects people under the age of 20. It is also often called an Oculocraniosomatic neuromuscular disease with ragged red fibers, and is usually caused by abnormalities that appear in the DNA of mitochondria. Some of the most common symptoms include limited eye movements, eyelids that droop, skeletal muscle weakness, heart block, loss of hearing, and diabetes, to name a few. This disorder typically progresses slowly, and while there is no cure, symptoms can usually be treated so they are not as severe. Kearns-Sayre syndrome likely decreases life expectancy, especially when serious heart issues are present, but the morbidity usually varies depending on how severe the symptoms are.

One of the first symptoms of Kearns-Sayre syndrome is usually limited eye movement, which eventually worsens until one or both eyes cannot be moved at all. Ptosis, or droopy eyelids, often sets in, along with pigmentary retinopathy, or pigmentation in the retina that may reduce the ability to see. Other physical symptoms may include short stature, skeletal muscle weakness, and ataxia, which is a condition characterized by difficulty coordinating movements.

There are other symptoms of Kearns-Sayre syndrome that are not as obvious, as they involve organs. For example, heart problems like congestive cardiac failure may appear, in addition to bradycardia, also called heart block. Thus, the heart may beat too slowly, often requiring either medications or a pacemaker to help improve both the patient's life expectancy and quality of life. Other symptoms that may not be obvious to others include dementia, diabetes, menstrual irregularity, occasional seizures, and deafness. While there is no cure for Kearns-Sayre syndrome, most doctors can treat each symptom individually.

The onset of this disorder is usually slow, as symptoms may start showing up in one side of the body, and then progress to the other side. Most cases appear in patients before they reach the age of 20, but this is the only noticeable pattern, since this disorder can occur in anyone regardless of sex or gender. It is usually a spontaneous mutation, though some cases are inherited, so there is no known way to prevent this condition. This disorder can result due to the deletion of DNA in the mitochondria, which are tiny rod-like organelles that exist in each of the body's eukaryotic cells. Their job is to provide energy to each cell, but they also control cell growth, cell death, and the cycle of cells in general, which is likely why mitochondrial disorders often affect so many parts of the body.