Kennedy Disease

Fact: Affects fewer than 1 in 150,000 males and does not typically occur in females

What is Kennedy Disease?
Kennedy disease is named after William R. Kennedy, MD, who described this condition in an abstract in 1966 and a full report in 1968.

​Kennedy disease, also known as spinal bulbar muscular atrophy or SBMA, is an inherited neurological disorder. Kennedy disease affects the specialized nerve cells that control muscle movement (specifically, the lower motor neurons), which are responsible for movement of many muscles of the arms and legs. It also affects the nerves that control bulbar muscles, which control breathing, swallowing, and talking.

Kennedy disease can also lead to androgen (male hormones) insensitivity which causes enlarged breasts in men, decreased fertility, and testicular atrophy.

Kennedy disease is typically an adult-onset disease, where symptoms occur mainly between the ages of 20 and 50. Kennedy disease affects fewer than 1 in 150,000 males and does not typically occur in females, who are protected by their low levels of circulating testosterone, accounting for the sex-limited inheritance pattern in this disorder.

Symptoms of Kennedy Disease
On average, symptoms begin in individuals aged 40-60 years. Symptoms come on slowly, and may include:

  • Weakness and muscle cramps in the arms and legs
  • Weakness of the face, mouth, and tongue muscles. The chin may twitch or quiver, and the voice may become more nasal.
  • Twitching of small muscles that can be seen under the skin.
  • Tremors or trembling with certain positions. The hands may tremble when trying to pick up or hold something.
  • Numbness or loss of sensation over certain areas of the body.

Kennedy disease may have other effects on the body, including:

  • Gynecomastia, meaning enlargement of breast tissue in males
  • Testicular Atrophy, where the male reproductive organs diminish in size and lose function.

How is Kennedy's Disease diagnosed?
Fortunately, there is a simple blood test today that checks a person’s DNA for the defective chromosome. Almost any DNA testing laboratory can perform the test. A doctor or nurse can draw the blood and send it off to the laboratory. Test results are normally returned within three-to-six weeks.

Treatment for Kennedy Disease
​Currently there is no known cure for Kennedy's disease. It does not affect life expectancy, so treatment is focused on maintaining the individual's optimum muscle function throughout his life through some of the following types of therapy:

  • Physical therapy
  • Occupational therapy
  • Speech therapy

These types of therapy are important for maintaining an individual's abilities and for adapting to the progression of the disease.

Adaptive equipment such as the use of canes or motorized wheelchairs can help maintain mobility and independence.

Want to learn more?
The following are organizations and/or websites dedicated to providing information and education surrounding Kennedy Disease. These organizations are dedicated to research, education, awareness, and/or support. They are listed in Alphabetical order without any preference or prejudice. Listing these organizations is not a recommendation or referral in any regard for seeking treatment or consultation or support for treatment.

Kennedy's Disease Association

Information on this page taken directly from:
Kennedy's Disease Association