Kearns-Sayre Syndrome (KSS) is typically recognized as a neuromuscular condition. In many cases, it is a multi-systemic disorder. This means it involves multiple organs and body systems. KSS also falls under the category of mitochondrial DNA (mtDNA) deletion syndromes or mitochondrial encephalomyopathies. Key features of KSS most commonly seen as indicated by the National Organization of Rare Disorders (NORD) include:
NORD estimates that 1-3 people in 100,000 have KSS.
Most cases of KSS are not inherited. Abnormalities in mitochondria DNA can usually be a factor for causing KSS. Mitochondria is how our bodies convert the energy we take in from the food we eat into a type of energy that can be used by our cells through oxygen. Individuals with KSS have a significant deletion of mtDNA. This means they don’t have enough genes to aid in mitochondrial formation and oxidative phosphorylation (how our energy is converted). More research is needed to further understand the cause of KSS features specifically. It may be linked to the lack of cellular energy due to the mitochondrial abnormalities. Mitochondria is an energy-producing cell structure. As a result, these abnormalities can lead to improper functioning in the muscles and brain.
Every single person with KSS has their own unique symptoms. According to NORD and the Genetic and Rare Diseases Information Center, people with Kearns-Sayre syndrome typically have an increased amount of cerebrospinal fluid protein concentration that exceeds 100 mg/dl. Individuals may also present with cerebellar ataxia and/or a cardiac conduction block. All patients have at least one of the above symptoms. Some have more. Because the condition is multi-faceted, it can interfere with multiple organs and tissues in the body.
“Every single person with KSS has their own unique symptoms.”
Additional symptoms as described by NORD can include:
How does KSS affect hearing loss specifically? Typically, KSS hearing loss is sensorineural. It’s also common for those with hearing loss from KSS to end up profoundly deaf at some point.
Read more: What is sensorineural hearing loss?
According to NORD, treatment for KSS is typically dependent on the features and symptoms an individual displays. For instance, those with heart problems may need a pacemaker. For others with eye and vision symptoms, eye surgery may be required. Hormone replacement may help those with hormone related symptoms. Since everyone with KSS doesn’t display the same set of symptoms across the board, there is no one-size-fits-all treatment. Individuals with KSS usually have a multidisciplinary team of specialists. The team can include a genetics team, cardiologist, ENT, and audiologist. Although there is no definitive treatment for KSS, there are investigative therapies such the “mito cocktail” that aids with mitochondrial enzymes and/or antioxidant therapy. However, these have not yet been FDA approved.