What does KSS Mean?

KSS stands for Kearns-Sayre Syndrome. The Kearns-Sayre syndrome (KSS) was first systematically described in 1958 and is one of the very rare, genetically determined mitochondrial diseases. The KSS has a core symptomatology with few symptoms, which occurs in all patients. Over the course of life, other serious diseases are added, depending on which tissues are affected by the mitochondrial defects. They must be treated separately.

What is Kearns-Sayre Syndrome?

The mitochondrial structural changes become visible under the electron microscope. CT shows calcification of the basal ganglia.

Kearns-Sayre syndrome affects about 12 in every 100,000 patients. The very rare disease is genetically determined and manifests itself in a disturbance of the intracellular metabolism. The DNA of the mitochondria in the cells is damaged by mutation at a total of 4977 base pairs . That corresponds to 12 mitochondrial genes. See AbbreviationFinder for abbreviations related to KSS.

These defective cells are found in skeletal muscles, extraocular muscles, in the liver cells. Since the mutated mitochondria can no longer (properly) convert the nutrients provided by food intake into energy for the cells, large parts of the muscles and the surrounding tissues are no longer supplied with adenosine triphosphate (ATP).

In contrast to other muscle-cell diseases, other tissues are also affected when KSS slowly progresses : Depending on which organs are no longer properly supplied with ATP, there is damage to the heart muscle, muscle weakness, hearing loss, diabetes mellitus, delayed onset of puberty, gastrointestinal problems. The first symptoms are usually diagnosed in the 10th year of life. There are only several hundred documented cases of the disease worldwide.


The very rare genetic disease only occurs sporadically, so medicine assumes that it is a matter of spontaneous mutations. Both sexes are equally affected by it. Mitochondrial mutations are passed from mother to child. In connection with the inheritance of Kearns-Sayre syndrome, physicians speak of an autosomal recessive inheritance.

Symptoms, Ailments & Signs

The basic symptoms of KSS appear around the age of 10. The patient has drooping eyelids (ptosis). Eye movement disorders (progressive external ophthalmoplagia, CPEO) are also evident. The pigment disorder of the retina (atypical retinopathy pigmentosa) causes visual disturbances and a restricted field of vision. Later, progressive muscle atrophy with impaired coordination of movements (ataxia) can occur. The reflexes are reduced (hyporeflexia) or no longer appear at all (areflexia).

If the heart muscle is damaged, conduction disturbances (arrhythmias) are the result. The impairment of nerve cells leads to sensory disturbances in the limbs. In addition, the patients have reduced hearing. Mental impairment, even dementia, can also occur as part of Kearns-Sayre syndrome.

The disturbed hormone balance leads to diabetes mellitus, hypofunction of the thyroid gland and growth disorders (short stature). Some patients also develop speech and swallowing disorders.

Diagnosis & course of disease

The main symptoms of Kearns-Sayre syndrome are evident early on, most of the others appear later as the disease progresses slowly. The liquor analysis shows a protein content of more than 100 mg/dl in KSS patients. The blood level shows increased lactate and pyruvate levels. The mitochondrial structural changes become visible under the electron microscope. CT shows calcification of the basal ganglia.

Reduced muscle activity can be detected with the help of the EMG. The stimulus conduction disorders can be determined using the ENG. A biopsy of the skeletal muscles shows a positive finding if 1.3 to 10 kb of the mitochondrial DNA is disturbed and the typical “ragged-red fibers” are recognizable. The electroretinogram visualizes the “salt and pepper retina”.

Cardiomyopathy (arrhythmia) is determined using an ECHO and an EKG. However, the doctor only has 100% certainty that the patient being examined has Kearns-Sayre syndrome once they have examined the entire mitochondrial DNA using PCR amplification and performed a sequence analysis of the destroyed mtDNA sequence.


The Kearns-Sayre syndrome leads to considerable limitations in everyday life and in the life of those affected. In most cases, the patients suffer from severe visual disturbances and a restricted field of vision. Complete blindness can also occur as the disease progresses. It is not uncommon for patients to experience heart problems, which can lead to cardiac death.

The sensitivity of those affected is usually limited and paralysis occurs. Most patients also have dementia or other mental disorders, so that they often depend on the help of other people in their everyday life. It can also lead to speech disorders.

Coordination of movement is also impaired, leading to restricted mobility or other walking difficulties. The quality of life decreases significantly as a result of Kearns-Sayre syndrome. In many cases, the parents or relatives of those affected also need psychological treatment to prevent depression or other psychological problems.

Treatment is with the help of drugs. In many cases, a heart transplant is necessary, since otherwise sudden cardiac death can usually occur. The life expectancy of the patient is significantly reduced by the Kearns-Sayre syndrome.

When should you go to the doctor?

Parents should consult a doctor with their children if optical changes appear in the eyelids. In the event of illness, these suddenly hang down and cannot be changed by intentional muscle tension. The signs of Kearns-Sayre syndrome develop by the age of ten and require medical evaluation and treatment. Eye movement disorders, visual impairments and reduced reflex reactions are considered unusual and should be investigated. In most cases, the affected person’s field of vision is limited. Decreased hearing, disturbances in heart activity or interruptions in the heart rhythm must be examined by a doctor as soon as possible.

If the child suffers from abnormal sensitivity in the limbs, it needs medical help. Feelings of numbness on the skin or hypersensitivity to irritation must be presented to a doctor. If there are memory disorders, irregularities in memory or reduced mental performance, a doctor’s visit is necessary.

In the case of short stature, behavioral problems and speech disorders, medical examinations are advisable. If the child complains of swallowing difficulties, refuses to eat or if there is weight loss, a doctor should be consulted. If there is insufficient fluid intake, the organism is threatened with undersupply. In order not to trigger a life-threatening condition, a doctor must be consulted. Patients with Kearns-Sayre syndrome need a doctor as soon as their symptoms worsen over time.

Treatment & Therapy

There is no cure for Kearns-Sayre syndrome. Patients generally have a lower life expectancy, which can be extended with appropriate medical measures. In extreme cases, cardiomyopathy can lead to sudden cardiac death. There is no causal therapy. However, in most KSS patients, the condition can be improved with the help of highly concentrated coenzyme Q10 (ubiquinone). Usually a dose of 30 to 260 mg is consumed orally.

Alternatively, 90 to 270 mg/day idebenone can be taken. The agents improve mitochondrial function in the brain and skeletal muscles. For other mitochondrial defects, for example, carnitine or creatine is also prescribed. Otherwise it can only be treated symptomatically. Regular visits to the cardiologist help in the treatment of chronic cardiac arrhythmias. In some cases, a pacemaker must be used.

If the condition is particularly bad, a heart transplant may even be indicated. The hearing loss can be compensated for at least for a certain period of time with a suitable hearing aid. Regular eye doctor visits reduce the risk of eye complications. If Kearns-Sayre syndrome is present, the prognosis depends on the severity of the disease, that is, on how many organs are involved in the disease process and on the proportion of abnormal mtDNA present in each of them.

Outlook & Forecast

Although Kearns-Sayre syndrome is very rare, the prognosis of the disorder is poor. The cause is a genetic defect that cannot and must not be treated. For legal reasons, scientists and medical professionals are not allowed to alter human genetics. The disorder cannot be cured with this. There is a symptomatic treatment that can only alleviate the existing symptoms.

The patient is exposed to long-term therapy, which is associated with various burdens and side effects. As soon as the treatment used is interrupted or terminated on one’s own responsibility, a recurrence of the symptoms is to be expected. Despite all efforts and medical options, many of the existing complaints cannot be treated.

In the case of mental impairments and disorders of the brain, there are usually no therapeutic approaches to achieve an improvement in health. In these cases, the patient is accompanied with the best possible means and a nurse is provided. Coping with everyday life is usually not possible. Due to the large number of disorders that are triggered by the syndrome, there can be a strong emotional burden for those affected and their relatives. Mental disorders can break out and lead to a further deterioration of the overall situation. This must be taken into account when making the forecast.


Prevention is not possible with Kearns-Sayre syndrome because it is a genetic disease. The exact genesis has not yet been clearly clarified. However, with the help of suitable medical specialist methods, it is possible to identify new symptoms of the serious chronic disease early enough and treat them in good time.


In most cases, those affected with Kearns-Sayre syndrome have no special or direct options for aftercare, so that the patient is dependent on a quick and, above all, early diagnosis of the disease. As soon as the first signs and symptoms appear, the affected person should consult a doctor to prevent the symptoms from getting worse.

Since Kearns-Sayre syndrome is a genetic disease, genetic testing and counseling should be carried out if you wish to have children in order to prevent the disease from recurring. Most sufferers of Kearns-Sayre syndrome are dependent on taking medication.

It is always important to ensure that it is taken regularly and that the dosage is correct so that the symptoms can be permanently alleviated. A cardiologist should also be visited regularly so that the condition of the heart can be checked permanently. In the worst case, this can lead to sudden cardiac death, so that life expectancy is reduced in many cases as a result of the syndrome. The further course of this disease depends heavily on the time of diagnosis, so that no general prediction can be made.

You can do that yourself

In the case of Kearns-Sayre syndrome, the most important self-help measure is to optimally adapt the medication to the living conditions. Since those affected are at an increased risk of sudden cardiac death, it is also important to look out for unusual symptoms and signs.

If heart ache, shortness of breath, pain and other signs of the disease become noticeable, the emergency doctor must be alerted immediately. In less severe cases, patients only have to take it easy. Strenuous physical activities should be avoided, as should stress and stimulants such as alcohol, caffeine or nicotine. Hearing loss can be compensated for with a suitable hearing aid. Eyesight can at least be stabilized by regular visits to the ophthalmologist.

If your health is particularly poor, you may need a heart transplant. In preparation for this procedure, the patient must change their diet and inform the doctor about any medication they are taking. Illnesses, allergies or complaints that the doctor may not yet know about must also be clarified before the procedure. After the operation, the patient requires rest and bed rest, accompanied by close medical care. What other measures the affected person can take depends on which organs are involved in the course of the disease.

Kearns-Sayre Syndrome