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Kearns-Sayre Syndrome
Sunday, 15 August 2004
Sunday, 15 August 2004

What

Kearns-Sayre Syndrome is a rare genetic disorder that is characterized by gradual deterioration of the retina of the eye, pigment or color changes of the retina and the progressive paralysis of the muscles that control eye movement (progressive external ophthalmoplegia). The first signs and symptoms of this disorder usually appear before 20 years of age.

Who

Kearns-Sayre Syndrome does not affect a particular racial or ethnic group and affects males and females equally. Only 226 cases have been reported in the literature, making this a very rare disorder.

Signs and Symptoms

The retinal degeneration with pigment changes and progressive paralysis of the muscles that control eye movement are classic findings of Kearns-Sayre syndrome. Other common findings are:

  • Cardiac conduction block - The electrical pathway in the heart is disrupted which can lead to rhythm problems.
  • Elevated protein levels in cerebrospinal fluid - The brain is surrounded by cerebrospinal fluid and normally there is a low level of protein in this fluid.
  • Cerebellar ataxia - The cerebellum is the part of the brain involved in muscle movement, coordination, and balance. Cerebellar ataxia refers to the loss of muscle coordination and balance Additional symptoms include:
  • Droopy eyelids
  • Muscle weakness
  • Swallowing difficulties
  • Loss of night vision
  • Hearing loss
  • Dementia (decline in mental function, including memory loss)
  • Cataracts
  • Short stature due to growth hormone deficiency (38% of cases)
  • Sex hormone deficiency
  • Diabetes mellitus
  • Hyperparathyroidism (increased parathyroid hormone, which is important in maintaining appropriate levels of calcium)
  • Exercise intolerance

Possible Causes

Kearns-Sayre Syndrome is classified as a mitochondrial DNA deletion syndrome. Mitochondria are the part of the cell that is responsible for energy production. Mitochondria are a unique part of the cell because they have their own DNA and when a piece of this DNA is lost (deleted) disease can result. Often times this deletion is not present in the mitochondria of every cell and the proportion of changed to unchanged mitochondria can determine the severity of symptoms seen in Kearns-Sayre Syndrome. Certain organs have higher energy needs than others and it is those organs that will be affected first in Kearns-Sayre Syndrome. These organs are the brain, heart, eyes, ears, muscles, and kidneys. Mitochondrial are only inherited from the mother. Most cases of Kearns-Sayre Syndrome, however, are not inherited. Mutations are sporadic, meaning they occur during the creation of the ova (egg cells) or during the growth of the embryo.

Diagnosis

The triad of 1) symptom onset before age of 20 years, 2) retinal degeneration with pigment changes, and 3) progressive paralysis of the muscles that control eye movement is necessary for the diagnosis of Kearns-Sayre to be made. At least one of the following must also be present to make the diagnosis: • Cardiac conduction block. • Cerebrospinal fluid protein concentration above 100 mg/dl • Cerebellar ataxia Laboratory tests are used to confirm the diagnosis. Creatine kinase levels may be normal or high, indicating that there may be muscle damage. Lactate and pyruvate levels are usually high, indicating that there is an abnormality in energy production. Muscle biopsy will also show abnormal fibers of the muscle tissue. Brain magnetic resonance imaging may show decreased size of the cerebellum or cerebrum. Prenatal diagnosis is available, but only in cases in which the mother’s mutation is known. Since the mother is usually not affected, prenatal diagnosis is rarely indicated.

Treatment

There is currently no cure for this syndrome. Coenzyme Q10 and L-carnitine are drugs that may be used to try and improve mitochondrial function. Because Kearns-Sayre Syndrome affects many organ systems patients must be cared for by a team of physicians including genetists, cardiologists, neurologists, endocrinologists, and ophthalmologists.

Prognosis

The prognosis of Kearns-Sayre Syndrome has improved with better and coordinated care by a team of physicians familiar with this disorder. This disease does affect many different parts of the body and this can lead to very serious medical problems. This disease does shorten expected lifespan and affected people typically live into their 30s and 40s.

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.

Weblinks

Foundation Fighting Blindness:
This foundation provides funding for research in diseases that cause blindness.

Mitochondrial Disease Support Group Online:
A support group for the online community. Also has links to other organizations and educational materials.

The Mitochondria Research Society:
This organization is mostly for scientists and physicians, but it provides information about promising research projects. Patients and families can sign up for a free newsletter.

Muscular Dystrophy Association
This organization provides information about neuromuscular disorders and services for individuals and families affected with such a disorder.

United Mitochondrial Disease Foundation
This website has a wide variety of educational materials and several personal stories. The foundation also provides support for individuals and families affected by mitochondrial diseases.

Google Search for Kearns-Sayre Syndrome

References and Sources

DiMauro S and Hirano M (2003). Mitochondrial DNA Deletion Syndromes. www.geneclinics.org/profiles/kss/ Posner E, Basu A, and Turnbull DM (2002). Kearns-Sayre Syndrome. www.emedicine.com/ped/topic2763.htm