Kearns-Sayre syndrome (KSS) is an extremely uncommon neuromuscular disorder that can affect several parts of the body, including the eyes and the heart.

The defect lies in the mitochondrial DNA. Mitochondria are responsible for producing the vast majority of the body’s energy. The cell starts to die when the mitochondria are not working or are broken. This means the body can not properly work because it does not produce energy.

Symptoms of KSS typically appear before a person becomes 20. Neither sexes are immune to Kearns-Sayre syndrome. Most commonly, the genetic alterations that cause KSS manifest during fetal development.  

The prevalence of Kearns-Sayre syndrome is quite uncommon. Between 1% and 3% of every 100,000 persons are affected by this illness.

A gradual loss of eye movement marks KSS until the eyes can not move, accompanied by drooping eyelids. It is also linked to an abnormal pigment buildup on the membrane covering the eyes. 

Some other symptoms may include: 

• mild weakness in the skeletal muscles
• heart block (a cardiac conduction defect)
• short stature
• hearing loss
• the inability to coordinate voluntary movements (ataxia), 
• poor cognitive function
• diabetes.

Seizures can also occur but are infrequent. 

There might be problems with hormone levels.

Kearns–Sayre syndrome is not always easy to identify. There may be multiple affected body systems.

So that doctors become more informed about the severity of the condition, numerous other tests are performed, such as:

• lumbar spinal puncture to check CSF levels;
• blood extractions to check for complete blood count; 
• urinalysis to check kidney problems;
• ophthalmological and audiological evaluations.

A patient could be referred for genetic testing and counseling by his physician.

A doctor may perform a muscle tissue biopsy to detect ragged red fibers, a sign of mitochondrial disease in muscle cells. 

There are a variety of imaging tests that can be used to rule out other potential causes, for example, the following:

• Radiological procedure using a CT scan
• Electroencephalogram (EEG)
• Electroretinogram (ERG, retinal exam)
• Ultrasound or spectroscopy (MRS). 

Treatment

At this time, there is no cure for KSS. Most of the time, what doctors provide is to treat the symptoms and offer support. 

Following up regularly with a cardiologist is crucial. Pacemakers are used to treat heart block and other electrical conduction disorders. 

Depending on which organs are affected, KSS requires a multidisciplinary approach to treatment, including audiology, ophthalmology, endocrinology, neurology, and neuropsychiatry. 

It may be best to use a hearing aid for a hearing problem and a cochlear implant, especially when severe or complete hearing loss. 

Hormone replacement therapy for the persistent decrease in hormone levels. Insulin administration for groups that oral anti-diabetic drugs can not address. And folic acid regimen for low levels of cerebrospinal fluid.

There is no way to avoid Kearns-Sayre syndrome. 

It is important to have a proper diagnosis as quickly as possible for Kearns-Sayre syndrome so that the symptoms can be managed and the potential consequences prevented.

Genomic analysis can help ensure a correct diagnosis and timely treatment. A care plan tailored to the specific requirements and goals should be developed in collaboration with your healthcare provider.

References

National Institute of Neurological Disorders and Stroke (2022). Kearns-Sayre Syndrome. Retrieved December 19, 2022, from https://www.ninds.nih.gov/health-information/disorders/kearns-sayre-syndrome

Cleveland Clinic (2022). Kearns-Sayre Syndrome. Retrieved December 19, 2022, from https://my.clevelandclinic.org/health/diseases/23036-kearns-sayre-syndrome