Kennedy Spinobulbar Muscular Atrophy – Causes, Symptoms & Treatment

Spinobulbar muscular atrophy Kennedy type

Spinobulbar muscular atrophy Kennedy type is a rare hereditary disease. It represents a special form of spinal muscular atrophy.

What is Kennedy Spinobulbar Muscular Atrophy?

Spinobulbar muscular atrophy Kennedy type ( SBMA ) is an x-linked recessive hereditary disease that belongs to the group of trinucleotide diseases. It is one of the hereditary forms of spinal muscular atrophy . Spinobulbar muscular atrophy Kennedy type is also known as Kennedy disease.

It is often confused with Foster-Kennedy syndrome. However, this is a different disease. SMBA is a disease of the muscles caused by nerve cells. It almost exclusively affects men who show muscle atrophy in adulthood . Kennedy disease was named after the American neurologist William R. Kennedy, who first described it in 1968.

Kennedy spinobulbar muscular atrophy is one of the very rare diseases. In Europe, a prevalence of 1:36,000 is considered probable. Doctors, however, assume a higher number of unreported cases. After evaluating genetic data, the scientists assume that Kennedy’s disease first appeared in western Finland. Spinobulbar muscular atrophy breaks out between the ages of 20 and 40.


Spinobulbar muscular atrophy Kennedy type is passed through heredity. The cause is a mutation of the X chromosome. The base triplet repeats itself, doubling or tripling the number. A base triplet is understood as meaning a molecular compound. The molecules are important for the structure of human DNA. The four known bases include adenine, cytosine, guanine and thymine.

In Kennedy disease, a CAG triplet is repeated several times on the X chromosome, which in turn affects the body’s hormonal balance. At the same time, there is a neurotoxic effect that leads to damage to the nerves. The effects are limited to the second motor neuron. However, degeneration only appears to occur as a result of further cleavage in the gene product.

Because women usually have an X chromosome that carries a trait that masks Kennedy disease, they rarely show any symptoms. However, they can pass the hereditary disease on to their sons up to 50 percent. In men, the anterior horn cells of the spine begin to die over time. This in turn leads to the breakdown of motor nerves that supply the muscle fibers. As a result, the muscle fibers also die off. The muscle weakness is first noticeable in the upper arms.

Symptoms, Ailments & Signs

The first symptoms of spinobulbar muscular atrophy usually appear in adulthood. These are non-specific symptoms such as muscle pain , tiredness and feelings of weakness in the limbs. The symptoms also include involuntary muscle contractions (fasciculations).

In addition, cramps and signs of paralysis are within the realm of possibility. If these appear more frequently in proximal muscle groups, it is advisable to consult a doctor. Throat and neck impairment also occurs in some cases, affecting the jaw muscles and tongue. In this case, swallowing and speech disorders can occur.

glottal spasm also makes breathing difficult . It is not uncommon for patients to also suffer from sensory disturbances in the limbs, such as tingling and numbness. Another typical feature are changes in the male mammary glands such as gynecomastia , in which the breast grows.

Diagnosis & disease progression

If Kennedy spinobulbar muscular atrophy is suspected, the attending physician first looks at the patient’s medical history. Since the symptoms are quite unspecific, this makes a differential diagnosis necessary. This means that other diseases that can be considered for the symptoms must be ruled out. Laboratory tests are also carried out. Elevated creatine kinase levels (CK levels) can be detected in the blood .

Sometimes there are also increased LDH and GOT levels. With an electromyogram (EMG) it is also possible to determine disturbances in the motor nerve cells. If there is already a concrete suspicion of Kennedy disease, the diagnosis can be made relatively easily with a genetic test. It is also easier to distinguish from other neuromuscular diseases such as ALS ( amyotrophic lateral sclerosis ).

In the event that the examining doctor does not yet have sufficient experience, it is possible that he will not classify the symptoms correctly and will make a misdiagnosis. Kennedy-type spinobulbar muscular atrophy is often confused with other myopathies such as ALS. In contrast to ALS, the life expectancy of SBMA patients is considered normal. However, over time some patients will require a wheelchair as a result of the disease.


Most of the complications of Kennedy spinobulbar muscular atrophy are due to the fact that the disease is often recognized very late or misdiagnosed. Symptoms are similar to those of amyotrophic lateral sclerosis (ALS). In contrast to this disease, however, life expectancy is not reduced in Kennedy spinobulbar muscular atrophy.

However, due to the constant twitching in the throat and tongue muscles, speech and swallowing disorders can occur in the long term. After a very long time, the ability to walk is also impaired. Although there is no cure for the disease, early symptomatic treatment can minimize its impact. The biggest problem is the constant diagnostic errors and the often agonizingly long time before the correct diagnosis is made.

The therapy initiated in the event of an incorrect diagnosis can even lead to an increase in the symptoms. At least the disease process is often not delayed. Wrong diagnoses and wrong therapies also wear on the nerves of those affected. Since physical activity can slow down the muscle deterioration process in Kennedy spinobulbar muscular atrophy, the importance of correct diagnosis is obvious. In addition to the muscular deterioration processes, wrong diagnoses and wrong therapies often lead to depression or other mental illnesses due to the resignation of the patients.

When should you go to the doctor?

With this disease, the patient is dependent on a medical examination, since self-healing cannot occur. The earlier the doctor is consulted, the better the further course of the disease. If left untreated, it can lead to serious complications and symptoms that can make life much more difficult for those affected. For this reason, a doctor should be consulted at the first sign of the disease. A doctor should be contacted if the person concerned suffers from severe tiredness or very severe pain in the muscles.

This pain also occurs in the form of rest pain and has a very negative effect on the patient’s quality of life. This can lead to severe cramps or even paralysis of the patient’s body. If these symptoms occur, a visit to a doctor is necessary. In many cases, problems with speaking or swallowing can also indicate the disease and should also be examined by a doctor. The disease can be diagnosed and treated by a general practitioner . However, the further course depends very much on the exact characteristics.

Treatment & Therapy

Unfortunately, it is not yet possible to treat the Kennedy spinobulbar muscular atrophy. Medicine has still not succeeded in finding a therapeutic solution for the hereditary disease. Research in this area is still ongoing. At times, some patients were given hormones such as androgens that slightly improved muscle strength. However, it remains unclear whether the improvement is actually due to the administration of the hormones.

In animal experiments, different substances such as leuproproelin showed positive effects. However, it will be years before a drug is actually approved. SBMA patients are advised to engage in regular physical exercise and exercise as much as possible. In this way, the deterioration of the muscle cells can be slowed down.


Kennedy spinobulbar muscular atrophy is a congenital hereditary disease. Therefore, no prevention is possible.


Since there is no causal treatment for spinobular muscular atrophy of the Kennedy type to date, it cannot be followed by any classic follow-up treatment. Instead, aftercare and therapy should focus on the symptoms of the disease and their consequences. If the disease causes pain despite drug therapy, additional drug therapy should be used.

Since the disease can be very stressful for those affected and their families, the focus of follow-up treatment should be primarily on the mental health of those affected. If depression or anxiety disorders have developed, they should be treated with medication and psychotherapy. In the event that relatives are also very burdened by the disease, systemic therapy can also be considered.

Behavioral therapy can also be used to learn how to deal with the disease. If there are additional sleep disorders due to the illness or the psychological consequences of the illness, these should also be treated. In addition to the administration of sleeping pills (Z-Drugs), this should also be dealt with as part of the psychotherapeutic care.

Since Kennedy Spinobular Muscular Atrophy is genetic and inherited, if the affected person or their partner is pregnant, prenatal diagnosis should be performed to determine whether the child will also be affected by the disease.

You can do that yourself

In order to limit the progression of the disease as much as possible, the affected person should train their muscles every day. In a medical treatment, physiotherapeutic exercises are automatically carried out to prevent muscle wasting and to support mobility. The patient can also carry out the training learned outside of the therapy hours on his own responsibility and independently. In addition, sporting activities should be carried out as far as possible so that the general movement sequences are maintained for as long as possible.

Although the genetic disease will not lead to a cure according to the current legal and medical status, it is advisable to work with a doctor and use your own funding opportunities in order to improve the overall situation. Situations of overload or physical overexertion should be avoided as a matter of principle. If it becomes difficult to breathe or if the first irregularities of the heavy strain appear, breaks should be taken. The organism needs time to regenerate so that no complications or irreversible damage occur. Regular training is also recommended if speech disorders become apparent.

In addition, methods of communication between the relatives must be developed in everyday life that are easy to use and can be handled easily by everyone. This makes it easier to cope with everyday obligations and improves social interaction. In addition, mental strength should be strengthened. Relaxation techniques can be used for this.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.