Basic facts about Kennedy’s disease
Kennedy’s disease (also known as spinal bulbar muscular atrophy or SBMA) is a rare disorder of the motor neurones, caused by a genetic mutation. The MND Association supports people with or affected by Kennedy’s disease. Select from the following to find out more.
“I have been diagnosed for more than 10 years and find knowledge of Kennedy’s to be very limited…information can be hard to find.” Person with Kennedy’s disease
The genetic mutation that causes Kennedy’s disease damages the nerves that control voluntary muscle movement. Kennedy's disease progresses slowly, leading to weakness, wasting of muscles and hormonal changes. Most people with the disease start to show symptoms when they are 30-60 years old, but it can appear in older or younger people.
There is currently no known cure, but symptoms can be managed to improve quality of life. Most people with Kennedy’s disease live an average life span.
Kennedy’s disease usually affects men. Most women who inherit the gene do not develop symptoms, but can pass it on to their sons or daughters. In rare cases, women may develop symptoms, but these are usually milder than those experienced by men. As little is known about Kennedy’s disease in women, further research is ongoing.
You can read more about the condition in information sheet 2B – Kennedy’s disease.
Similarity to MND can cause confusion at diagnosis and you may have many of the same tests as for MND. These are used to rule out other causes. See How is MND diagnosed? for details of these tests.
However, a clear diagnosis for Kennedy’s disease can be made through gene testing.
Kennedy’s disease affects people in different ways. Not everyone develops all of the symptoms and they can be very mild for some. Support can be given to help you achieve the best possible quality of life.
The main symptoms for women are muscle cramps and fatigue. However, it is unusual for women to develop any symptoms, even if they carry the gene responsible for the disease.
The symptoms of Kennedy’s disease in men are:
- fatigue, making it harder to do the things you want to do
- twitching, with rippling sensations under the skin (known as fasciculations)
- tremors and muscle cramps, which can be uncomfortable
- muscle weakness, with loss of muscle mass (wasting)
- enlarged breast glands, leading to growth of breast tissue
- reduced sex drive, and difficulty getting an erection
- reduced fertility, from hormonal changes
- swallowing difficulties, affecting how you eat and drink
- slurred speech, affecting how you communicate.