What is Kearns-Sayre syndrome?
The Kearns-Sayre syndrome is an uncommon neuromuscular condition that affects those below 20 years of age. The condition is generally characterized by a progressive paralysis of the eye muscles, discoloration of the retina, and cardiomyopathy. The condition is also identified to manifest CPEO or chronic progressive external ophthalmoplegia. The said condition is a multi-systemic disorder that is progressive and can gravely affect the life of the affected child.
A Child Exhibiting Weakness of the Eye Muscles
The condition’s name has been coined by two known patients of the syndrome, Kearns and Sayre. They manifested the triad symptoms of the disease in the year 1958. Before the condition was fully recognized, the two patients were the only reported cases of the disease. Later on, the condition was recognized and acknowledged after 5 new cases presented the same presenting symptoms of the disease. In epidemiological reports, the condition is considered rare as it has prevalence rate of 1.6 out of 100,000 people of the Finnish population. However, England has a 1.7 prevalence rate out of 100,000.
Kearns-Sayre Syndrome Symptoms
This progressive disease is basically characterized by the triad manifestations. The eyes are mainly affected and not sparing a number of other body organs. The following are the manifestations of the syndrome:
- Eyelid drooping or medically known as ptosis is observed. There is absence of control of the eyelid that results to drooping.
- Degeneration of the retina is observed. There is accumulation of some pigments on the membrane protecting the eyes. Cataract development is a possibility.
- External ophthalmoplegia is noted. This is lacking of eye movement coordination.
- Cardiomyopathy is noted that eventually results to a heart block.
- Skeletal muscle weakness is also reported.
- Hearing loss is also a manifestation.
- Coordination is affected. There is lack of coordinated body movements known as ataxia.
- Cognitive function is altered.
- The affected may develop diabetes.
- There is a possibility of seizure problems.
- About 38% of cases have a short stature build.
- Hypogonadism is noted to some patients. This is the underdevelopment of the gonads resulting to low testosterone levels in men.
The Progression of Eye Muscle Weakness Ending in Severe Weakness
Kearns-Sayre Syndrome Causes
The Kearns-Sayre syndrome is acquired as secondary deletions in the mitochondrial DNA. There has been a number of single deletions and rearrangements of the mtDNA. The condition is not considered as inherited but is developed spontaneously. This is related with the uniqueness of one’s embryonic development.
The condition is basically not inherited but is acquired via mutations of the DNA after fertilization. The so-called mutation is considered somatic and is only present in some cells. There are some cases where maternal inheritance is considered, but is a rare phenomenon. It has been noted that about 1 out 24 cases provide proof of maternal inheritance. There is no certain group of sex affected of the disease. Men and women are equally affected by the syndrome.
Diagnosis can be attained through the following tests:
- Checking the pH and glucose levels in the urine specimen assist in the diagnosis of the syndrome.
- Blood levels of creatinine may be elevated with this syndrome. Lactate and pyruvate levels are noted to be elevated.
- An MRI can help identify myopathies.
- A confirmatory test is through muscle biopsy of the orbicularis. As a result, mutated mitochondria can be identified. The muscle fibers shall also contain Gomori trichrome stain.
- The cerebrospinal fluid analysis shall have elevated protein levels. The CSF can be obtained from a lumbar puncture.
Kearns-Sayre Syndrome Treatment
A direct cure of the Kearns-Sayre syndrome is not yet made available. Management of the disease process is the aim in the treatment course for the disease. The following are the proposed treatment for Kearns-Sayre syndrome:
This shall depend on the presenting symptom of the syndrome. When the patient is suffering from ptosis, there shall be a surgical correction of the levator muscles which is responsible in the elevation of the eyelids. Cochlear implants are also performed when deafness has been noted among the affected.
The client is required to have supplementation of coenzyme Q10. Another is folinic acid that can provide improvement from the syndrome.
Physical activity is recommended to patients in order to avoid development of myopathy. A therapy may also be necessary as muscle weakness is prominent among the affected.
The condition is considered as progressive that its prognosis is considered as poor. Since the affected are mostly below age twenty, by the time they reach thirty or forty, death may be anticipated.